Heat Pumps vs. Electric Hot Water Debate
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- เผยแพร่เมื่อ 12 ส.ค. 2023
- Are heat pumps worth it? Mark debates with Karl Jensen from iStore about heat pumps versus old-school electric element tanks. Turns out the results are surprising!
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Great video. Got rid of my instantaneous gas hot water system and installed a heat pump. Now running it 100% of PV and batteries. Also no more running out mid-shower to change over the bottle when it runs empty.
Awesom! Getting rid of instant gas is a big win in anybody’s books. Nice move!
bottles about the most expensive form of Hot water heating, emissions disaster too as have to truck them around
@@mcelectrical - Our South Australian Government has got no plans in getting rid of gas as a domestic fuel. Our Premier only said last week that "South Australia will not follow Victoria's lead".
This is the level of stupidity and pig-headedness (and basically, corruption) that we're dealing with over here.
Installed an Istore in parents in laws place in Nundle, which regularly gets frosts. The local electrician said it wouldn’t work. After a year and a very cold winter it’s worked faultlessly. The lesson I’ve learned is that often local trades don’t want to try something they havnt worked with before. We have had Sanden heatpump hot water split systems in tenterfield for 10 years now and they work well in our very cold climate.
That’s a great story for old tradies like me. It’s pretty hard to switch mentally. I appreciate you sharing, Mark.
@@mcelectrical understand. We all work with what we know and trust. Love how you are using your channel to be challenged and introduce new ideas. Do agree that fronius and BYD is the best thing. Just installed a 30kwh battery with a new Gen24 to augment our system.
dang! thats a lot of storage. @@simonh6788 i cant make the economics work anytime other than peak time and using that much during peak time seems impossible, curious as to your use case
got a heatpump 18 months ago in melbourne. use a simple timer device to align it with my solar panels output as well as off-peak electricty costs. works a treat!
Does the heat pump work fine in Melbourne's winter?
In the US here. I have a 50gal heat pump water heater. For our household it works fine, venting the "cold" air into a basement cold storage room. The hardest part about the design of my installed unit is replacing the sacrificial anode, which I should be doing this year to keep up with the hard water buildup from our well. Everything else has worked well for 4 yrs so far. Uses about a tenth of the amount of power we were using on the old electric resistance watertank.
glad to hear its working well - note that heat pump evaporators need to run below the surrounding air temp to be able to harvest heat from the air - the magic number is 7 degrees, below that the efficiency of the heatpump drops considerably. guessing the old system had a leak or was poorly insulated and new one much better. Poorly insulated pipes can increase the standing losses significantly.
"venting the "cold" air into a basement cold storage room" ? Not that easy IMO. The heat pump needs to replace that air. So forget about a "cold storage room" Why ? because the entire basement will become cold storage or will need to be heated. The heat from your basement is going into the hot water system. The discharged air from the unit will be 20 to 30 degrees F lower than the basement temperature. Depending on hot much hot water you need, will determine the temperature of your basement. Thes units will only be perfected IMO when they can use, 100% outside air , like a 99% gas furnace, using a piece of 4"pvc pipe, for outside air intake, and exhaust. A mini-split heat pump can produce usable heat at -20F on most new units. That is when I'll buy one, otherwise I am not willing to heat or freeze my basement. BTW, I am glad, you are happy with yours. This is IMO.
have you looked into water softener and a whole home water filter? The funny thing is those fridge water filters that are 5 inches long by 3 inches wide cost 50 dollars and its 200 gallons. Our whole house water filter a few hundred for the unit, and it does 50k gallons. With replacement filters around 110 dollars a piece. its amazing how much savings there is for those who look for it.
they can be vented to outside and use outside intake air, the guidelines are if it drops the room temp more than 7 degrees, you shouod vent to outside. @@freddozer1399
I had 1 heat pump installed in my cabin (250 sq. ft.) and 2 in my garage shop/loft ( 24'X24') in Maine. I find that heat pumps work well into the teens (F) efficiently. However, anything from the high teens and lower, the defrost cycle runs at least every hour, when no heat is provided, and the amount of electricity used goes way up. In such low temps, I resort to either my propane wall heater or an electric/oil portable heater. They provide heat much more consistently and cheaply when it gets really cold. @@karlajensen100
Installed the 180 litre Istore heat pump earlier this year and at the same time did away with the gas connection to the house alogether. With the solar sponge tariff here in Adelaide, even on a cloudy day, it doesn't cost much to heat the water. Having 12.9 kw of solar helps.
Nice Ryan, I’d love to hear your story over time…
Ie. does it last, and how is the warranty.
hi mate, may I know how much you paid and how is the performance ? I live in Adelaide too. Please update. Cheers.
@@coolmanu55 the Istore has been performing very well.
It cost me approx $2400 after the rebates.
Fantastic episode- would love to see a comparison between solar hot water and heat pump in QLD
My air to water heat pump is now nearly 20years old and as efficient as the day we installed it (modern ones are better) We live in Norway so we have a different type of extreme weather. But I’m guessing it has to work harder plus all heating is from the same unit (under floor). Love it! And it has for sure paid for itself. Next one will be ground source.
Same here have Australian made quantum 315l 22yrs old
It was as given to me as house previous servicing was been knocked down so it’s on its second house. We have 10 people in the house for Xmas every year always hot water for dishes and showers.
They’re a bit noisy. This is there only down side.
Sadly it seems a lot of people aren’t great at maths.
Hence the slow take up of heat pumps.
Brilliant. As a Melbournite, this is great!
Excellent advocacy Karl and interesting to see Mark admitting that sometimes a more complex technology can produce better overall outcomes….
I’ve got a Reclaim heat pump, it’s great. Uses just 2 kWh of energy each day from solar. I’ve been really happy with it, it works well!
Yeh nice. Glad you didn’t listen to my old
Advice :)
Same here, it's so quiet too.
great video. I cannot understand why we don't try to get a double whammy benefit from our heat pump hot water systems. Why don't we pump the "waste' cold air from the heat pump into our homes in summer to cool them
Yeh I’ve heard that suggestion a few times. I guess the cost of the infrastructure to do that would be pretty high. But maybe someone will design a cost effective product some time.
This was planned in our new house build. A 15Kw inverter with 52 x 375w panels pushing 80 -100 kW daily into the grid in summer on a clear day, the FIT atm is 7c The 315L standard hot water tank was retro fitted with a timer turning on at 8.30AM and turning off at 1PM . 1 deep freezer and 2 large fridge freezers We have never had a bill and are always in credit. House has a skillion roof facing due north. If you don't have solar or a small system and you need to replace your hot water tank then a heat pump would be the way to go
Could you do a video on the various heat pump water heater options in Australia? For example, I assume you might combine with house heating in Melbourne but probably not in Cairns?
That’s a question for Karl. I’ll ask him if he has any interesting input and maybe we should do round 2.
Could you please compare with gas heating system vs heat pump water system ?
Hey, i am looking at putting in a solar system ATM and was considering the catch relay. from these calculations here you did not add that to the Heat pump system. i have a heat pump HW tank is the catch system not recommended with a heat pump system?
I still run a 24 Tube Evacuated Tube collector and Stainless Steel tank. System has been flawless for 15 years now and still going strong. We only boost on average 5 days a year at most. $6000 initial outlay for 15 years of hit water, has been good value for us.
In the US, we installed a hot water heater with a heat pump and, after incentives from the government and our electricity provider, the cost was only a couple of hundred dollars more. The ROI on this unit will be realized in right around 18 months, with decreased operating costs from then until it needs to be replaced. As a nice bonus, I route the output from the "air conditioner on top of a hot water heater" into my garage, providing cooling during the warmer months and avoiding the condition where the heat pump and propane-fired heater are working against one another.
I have an energie system with panel on the roof (condenser from heat pump). After installation I complained it wasn’t cheaper than normal electric. After five years change of ownership the new man diagnosed a faulty green board, replaced it and now it runs cheap hot water
Well presented Mark and Karl. 👍👍
Thanks Kai. This one was a labour of love. Took me a while but it was totally worth it.
In Canada here, and my HeatPump hot water system uses 800w when running in ECO mode (heat pump only). This is ~3200W Less then the average all electric tank sold in Canada (where our inlet water temps can be as cold as 1-5'c). My previous tank was Gas, and it was costing me ~1200/yr in heating costs, besides my gas powered furnace (which has also been replaced with a cold climate heat pump heater/ac unit). My total gas bill each year (with taxes and tarriffs, was ~ $5600/yr). My new system, Even on full heating (excluding the backup unit, which on average will only run 1-2 weeks/yr), will cost me $2800/yr. It will take me about 12 years to amortize the savings for both hot water tank AND HVAC unit replacement. Next year, I add Solar, and that will drop my amortization period to ~6-7 yrs. Going Heat pump is TOTALLY worth it, but it does have a high up-front cost in Canada ATM (my all in price for both units, including electrical work, panel upgrade, etc, is $40k). So obviously future replacement will be cheaper, as I'll have the infrastructure in place to be all electric, and I'll have PV then. The numbers simply don't favor old-school resistive tanks anymore.
Well the manufacturer should build in redundancy, fit a resistive element in the tank also so if and when the heat pump components die they could fall back to that to heat the water, the tank could still be serviceable. And with the way solar feed in tariffs are going with lower rates and to the point it costs you money to feed in, they could direct excess solar electricity into the resistive element to heat up water faster if needed.
Question is. What temperatures do these two different types of equipment achieve/provide. (And under a range of ambient temperatures from zero to 40 degrees C) ?
howlong the lifespan is for the heat pump? If you google the heat pump hot water, most people complian about it's failure after 3 or 4 years.
While it’s a compelling case for those shifting from gas, or those with a HWS close to the end of it’s life, we’ve got a 3yo electric 250l HWS with a 1.8 kW element, and have been heating our water with a Catch Green set to “solar only” (100%) for 5 months now (2 person household with a 5kW daily HWS load)…..
As a result, the outcome using the calculator, based on $1000 to supply and install the Catch Green and 100% solar heating, was $2460 (to heat using our existing HWS) vs $3965 to replace the HWS with a heat pump.
We’ve recently upgraded our solar (single phase with 12kW on the roof) and have noted we’re export limited to 5kW for quite a few hours most days, so an additional saving opportunity would be to defer HWS diversion heating (ironically, using a timer connected to the Catch Green!) to access the ‘free’ power that would otherwise be lost. If we managed to heat for half the time from this free power, the effective FIT would reduce from 8c to 4c, which would further reduce the 10 year cost from $2460 to $1730….
So, my advice would be to check your specific circumstances before concluding that a heat pump wins (when our HWS wears out, hopefully in 10 years + 🤞🏻, we’ll revisit our situation based on the power cost and FIT at the time ….). Of course, an added consideration is the life of the diversion device …. we’re hoping the Catch Green diverter will outlast its 5 year warranty… 🤞🏻
Kicker here is when you buy an EV, every kWh you put into it is worth $1 to you vs buying Petrol. likely wont have enough spare PV and economics of upgrading to three phase and adding more solar vs ditching the element and using that power for your EV are exceptional
@@karlajensen100 …. yes, that’s what prompted us to upgrade the PV on single phase (currently exporting 30kWh on sunny days, after self-consuming 10-12). We rarely drive more than 60km most days, so am going with a PHEV (latest model Mitsubishi Outlander, with a larger 20kWh battery). Reasonably confident that we’ll ‘fuel’ it most of the time with excess PV…. using a Fronius Wattpilot, that MC Electrical are installing this week (darn long wait-list for the vehicle …. signed a contract and paid a deposit nearly 12 months ago).
This is a part of my all electric home in an area of the US that gets so cold that Aussies may have trouble conceptualizing.... (I do switch it from heat pump mode to hybrid for the winter) we touched -28C without factoring in the wind last winter for about a day... as a heat pump installer who has many customers who are all electric and some were on holiday, the only issue that arose was my stress level! I mean when it's so cold that an ICE doesn't want to start and you can still get heat out of outdoor air, the tech has come a very long way.
i'd like to see that but post a video as i dont want to see -28 in person , makes little difference if thats F deg or C deg its still bloody cold!
I wouldnt want to live there either @@bobguy6542
I’m looking into heat pump hot water in 3 phase setup in 2024 with smart shift tech, the relay thing you mentioned didn’t end up come out in 2023.
Had to install a new compressor for my mom and dad’s AO smith heat pump wh. As always, 9 months outside the warranty…
Does the i store work with my green catch power? (i assume the electric element component). i’m using my hot water as a cheap energy storage alternative to batteries.
No, you would ditch the green catch and sell it. This would likely only be viable if your existing electric tank fails and you still have a cost effective albeit without any environmental benefits the heat pump does as it doesnt reduce the $$ you spend
I got 20 years out of my 400ltr rheem element hot water system changed out 1 element and changed out the anode a couple of times to keep the rust / calcium at bay
Yeh that’s solid! I’ve seen the last 25 years, but they were copper tanks. With Istore, the tank may last the same time as any other tank. If the heat pump breaks down, you can just use the element in the tank to keep going. It’s kind of the best of both worlds.
Can we get a list of companies from istore in NSW that are installing the istore tank as part of the NSW hot water system rebate, all I can find are installers using the chromagen tank which are rubbish
Great question. I’ll ask Karl to chime in.
Also consider the STC rebate when you purchase a heat pump. Mine was $850 in QLD
Yes, that was taken into account with the price of the system.
@@mcelectricalwhere can you get a HPHWS installed for $3500? Think you will find an istore installation is a lot more than that
It pays off - a lot fast if you have enough surplus solar power and especially if you get the right one with an additional heat exchanger aka coil
Those generate from surplus power hot water up to 62 C by the SG ready feature (in fact the hot water heat pump has 2 power connections where one of these is only powered if there is surplus power) and then can exchange the surplus energy into the oil / gas heater via the heat exchanger.
In case of surplus power available the SG Ready line gets power and the heatpump switches from your usual heating schedule like 55 C in the morning from 6 to 10 am and 4 to 8 pm to a full speed 62 C surplus power mode until it switches of. In case of such cloud it continues to end the heatpump cycle first by the remaining grid power.
These 270 Liter ones with heatexchanger come for 1900€ incl. 20% VAT and are easy to mount cause you simply replace the boiler.
They save about 2€ of oil a day for hot water compared to current consumption and additionaly heating the home by 3/4 in such surplus mode which equals 1000 liter oil lor 1000€ , so in total 1700€ in case you have 16 kWp and a LFP battery
The heatpump heat exchanger for heating should deliver more benefits than you calculated cause I bet you have a higher and more consitant solar power output per kWp installed than we here in germany with about 1100 kWh per kWp if we have a good year and a solar roof facing south.
You calculate only hot water, but the heating function delivers a lot. Of cause the 1700€ savings has one downside: you feed less into the grid and loose here 0,08€ per kWh which is lot less than the 0,32€ we pay for the grid. Therefore you can expect to invest 5000 kWh to gain 17500 kWh of heat as hot water and loose 400€, so in total 1300€ net savings which pay of the whole hot water heatpump within 2 years.
For example Atlantic Explorer V4 is a hot water heatpump with such 16 kW heat exchanger. And in Australia you will even score higher savings cause when do you see temperatures in winter below 5°C or below 0°C. You can save about 1500 Liter up to 1750 Liter of oil depending on the sunshine during the winter.
And those heatpump offers 2 heating options: the heatpump compares the temperature outside and the kWh price with the oil price and makes a decision to heat by power or let the gas / oil heater heat the home cause in low temperature situations oil is cheaper. You can also run it differently which means the oil / gas heating measure the temperature of the circulating water for the heating. If it drops below 50 C it turns on as usual and heats up to 60 C till and then waits. If meanwhile sun comes out, surplus power is back again then that heating water will be heated by the heatpump which can run with up to 750 W that equals up to 3 kW .
In coldest nights below zero it can also turn on a 1 - 2 kW heat element in the hot water tank.
But the major difference is the heat exchanger to run your central heating from the solar surplus power instead of oil or you can even run it from the grid if that is cheaper than oil. Here it is slightly cheaper depending on temperatures so 80% - 90% of the year.
And it is astonishingly easy to mount such system: fresh water and circulating hot water and hot water are the same of a boiler connected to the gas heating, then you have the 2 tubes or pipes connected to the gas heating and 2 power lines, one connected to the grid and one is a switched connection if surplus power is available.
And it will pay of a lot faster than just the hotwater heatpump alone without such heatexchanger which is roughly 400€ more, so 1500€ for 270 L heatpump and 1900€ with heatexchanger. Of cause 1€ equals 1,7 $ AU if you want to do the math. The product mentioned above Atlantic Explorer V4 is a french product with english manual you should be able to download. It really will pay of the hot water heatpump with heat exchanger a lot lot faster than then a pure heatpump without coil.
thats a chunk to read, perhaps shorter would encourage more to dive in
Are there any state rebates for upgrading home hot water systems? I'm in NSW and I know there is a rebate to upgrade old element hot water systems to new heat pump systems, but not sure that rebate extends to gas systems.
I’m unsure it there is in NSW. There is a new heat pump rebate in qld
@@mcelectrical Any chance of getting a discount for your viewers from iStore?
still love my quick recovery GAS HOT WATER system , using NATURAL GAS , still use my two stroke lawn mower and my two stroke 500cc dirt bike n 20 to 1 petrol / oil ration, love nothinbg more than to wake up in the morning to smell that stroke running in the morning.
thanks Craig fracking is really good politically . vic is unable to produce enough gas from Bass strait for everyone by 2025 so alternatives are going to cost you a lot. 500cc is alot of dirt bike - guess you can ride! I cant so I have a stealth bomber which wouldnt be nearly as fast but i can ride it places you would get arrested so i find it enjoyable
Here in Michigan USA, it's cold a lot. We use Geothermal for heat and cool with a desuperheater to make hot water as well. While the desuperheater doesn't cover ALL of our needs it coves the vast majority. My monitoring system showed that in 2022 I spent $110 on the old school electric heater to provide the remaining hot water. So even if a heatpump water heater were to make that $110 be ZERO, it would take 20 years to pay for the heat-pump (approx $2,000 here in the U.S.) BUT even that miracle ignores that the heat that unit extracts from the air MUST come from somewhere, and that somewhere is my home. Given that my home is now cooler my goethermal needs to run more to compensate. That unit is (ish) 400% efficient but still I have to pay to run that, meaning the 20 years likely becomes 25 years for payoff. It won't last 25 years, yet here in the U.S. I may soon be told I MUST use a heat pump which will with hear certainty, COST me money!
Great debate and outstanding to see technological advances helping us all save money and emissions. Put a HP on dads place years ago, amazing results. Get a HP!
There we go. Another solar industry expert - with no bias- recommending heat pumps. Seems I was late on this bandwagon! Thanks Nigel!
What about instant gas hot water unit worth the swap ?
I wish you'd included a column /calculations for a no-solar installation. There are a lot of people that need to replace a water heater but aren't ready/able to go solar yet. A whole category of people and use cases that were left out.
Good point. You could just enter zero solar production into the calculator.
In NSW, I just had a heat pump hot water system installed - it was mainly funded by government subsidies - only cost me $33!
Wow! That’s a decent deal!
Just had an almost silent Sanden ASHP HWS installed in inner SE Melbourne. Data collected for just over half a month indicates an average of 3 to 3.3kWh daily energy use.
So, you’d be using four time that if it was an electric element.
@@mcelectrical Do you mean 1/4 that of an electric element, possibly less? I should have added that the tank is 315 litres in volume.
@@mcelectrical the Sanden has an inverter drive, costs double what an Istore does and achieves 10-15% better performance so est would be 12.45kWh for an element tank
Great video
I'd love to see a companion of heat pump to gas storage and continuous flow
That’s a bit above my pay grade :)
I would like to see a comparison between the heat pump and solar hot water. Many people still installing solar hot water systems. Mine will need replacing in the not to distant future and I’m not sure yet wether I should replace or change to a heat pump. Had so many issues i feel like the roof space would be better served with more PV. It’s not free hot water when you forgo the extra panels and you still have an element using power.
Yeh, I would probably be installing more solar pv and a heat pump!
Install more PV Solar. I hooked up a 320ltr H/W system I was given to offset using an instant gas H/W system I already have installed. I put an 1800W element in it after it blew a 3600W element 6 mths after install to reduce power usage if weather was cloudy & run it on a timer. This give our family of four plenty of hot water using only 4-5kwh/day or less. With 10kwh of solar & a battery in Hervey Bay we get $30 - $70/mth back from our power supplier.
I have a heat pump hot water service in Melbourne with PV. It's unlikely that 90% of the power comes from solar. Generally, people have showers in the morning or at night so the best you can hope for is that the system is recovering during off-peak power.
You would still need a reasonable sized solar system, and heat the water during the day. Some heat pumps have timers built in. It really is site specific - so that’s the reason for the calculator
Our hw tank is in a large indoor cupboard inside the house, will a heat pump iperate in an environment where its not ventilated.
no it would need to be relocated outside. upside is you'll gain a cupboard!
What wasn't covered was the EER varying with ambient temperature of the refrigeration system, meaning the 'efficiency' between Melbourne and Brisbane would have to vary (potentially significantly?) for a heat pump, im sure it wont be 400% in Melb. The other thing that concerns me is how well (and reliably) they perform in climate zones 7 and 8, where the small boxed window Ac's freeze into an ice block when heating in the morning with a high dew point, then require long periods of defrost.
Hi Jamie - I'll take this one! The Peak EER is >6 but its not representative of a broad range of operating conditions so we don't shout it from the rooftops. Istore still achieves COP 4 at anything over 6 degrees and there is no-where in Australia where average daytime winter temp is below 5 deg according to the BOM. by the time you're at 0 degrees that COP is 2.
It also varies with tank/water temperature as the hotter the tank is the larger the temp differentials and thus larger gas pressures required to achieve and a corresponding loss of EER. Refrigeration is the very first topic of thermodynamics in engineering and is very well understood. The fact we can achieve average EER of 4 over heating 270L of water AND 100kgs of steel is really incredible however vs an airconditioner their design can be optimised for heating only and space constraints are less critical (indoor unit heat exchangers size).
For climate zone 7 (TAS and a small portion of Vic/ NSW) the Istore is installed in their thousands - Energy point in Tas distribute Istore. For climate Zone 8 alpine regions, we have a number of units installed and there are many challenges in areas where the water freezes above ground and specific advice and expertise is needed. I would advise the use of supercritical CO2 units in alpine areas as their efficiency at negative temps can still be quite good, as the cost of gas in these areas is HUGE=, heatpumps make really good sense when properly designed.
Ok makes sense, that’s great info thanks Karl, and noted on the CO2 supercritical for alpine zones. You and Mark have certainly convinced me, with those financials you cant lose!
Thanks so much to you and Mark for the great video
@@karlajensen100
Hi Karl, could you please confirm if the Istore HP runs an anti frost cycle? (I assume so) Other HP's override the the daytime timer as a priority to perform the anti frost cycle, hence this then means that the hot water will now have done its heating outside of solar hrs, not using the sun the next day to heat and a further increase to the stated kw usage. In colder climates this has a real impact on the $ saved. @@karlajensen100 @mcelectrical
Sanden heat pump in Sydney runs during the day on mostly of solar.
I’ve only heard good things about sanden. Expensive and really good.
Except for their 'frost cycle' overriding the power usage outside of solar hrs. Which is not stated in the specs. Colder climate problem. @@mcelectrical
How does PV redirection to the heat pump work? Can I feather my excess PV (meaning that above what I can export and use) to the electric element of the istore? It seems wasteful to start stop the pump all day long.
You can’t really do much except have a timer. But because the load of the heat pump is relatively low (under 1kW) then it will usually sit under the export curve of a decent system.
Wise to remember to inspect the anode yearly as per the warranty
Good point. Cheap and easy preemptive maintenance.
Basic electric hot water hands down for me. I've had 2 heat pump systems (rheem and thermann) and both crapped themselves around the 4 to 5 year mark (just outside warranty). Very expensive to repair ( so there goes the money you THINK you have saved) that's if you can find a serviceman who knows what he's doing. If anything goes wrong with my electric system I can change the element and thermostat in 20 minutes for $70.
Yeh, that is the way I used to think about it. And maybe it’s still valid. It really depends on the quality of the heat pump.
Wow! The costs stated here are wrong. For the last 10 years adds up to just over 4k including purchase of standard tank.No solar. Family of 4, 250 litre
No kidding. I absolutely do not believe the hype surrounding these wildly complicated devices. One look at the cutaway diagrams on You Tube shows a water heater packed with components that will fail. Why? Because everything eventually breaks. Anybody here have a fancy fridge that crapped out after 10 years? A washing machine that saves money until it breaks after a decade? My house has two electric water heaters, one of which is 37 years old. You read that right: thirty seven years. It was installed in 1987 and I bought my house in 1995. Repairs? NOT ONE. No thermostats, no elements, no nothing. For that matter, the Lennox heat pump outside my house is also 37 years old. ONE repair, a $1,200 compressor, in 1996. That’s it. NO appliance or HVAC device manufactured today can begin to match the durability of this equipment, for the simple reason that efficiency is pushed to the limit and production costs are cut to the bone at every turn. Buy basic appliances and maintain them, and hope for the best is about all you can do these days. As for me, I will keep my ancient water heaters instead of spending $4,000 for a fancy heat pump model.
Pay attention to the (correct) maths because you could replace it multiple times and still come out ahead.. can't see how anyone can back an element over heatpump given the cost of electricity and total cost of ownership.
I have had a Rheem heat pump, it lasted 7 years, it was undercover. It did not last long enough 7 years, WOW that was SHIT.
Is it possible and or feasible to install a seperate solar circuit for a heat pump? I only have a 5kW inverter but have lots more space on the roof to go beyond 6.6kW of panels.
Not really. Heat pumps need a steady source of power (unlike an electric element). However, depending on where you live, rules have changed and you more than likely install more than a 5kW inverter.
@@mcelectrical I believe the max is 5kW in WA
@@mcelectrical Are there any issues using heatpump HWS with solar PV and a Catch Relay?
@@jpharri Could be done but having done it myself with the Fronius energy management relay there will be days when not enough solar = cold showers. We find most reliable is the two timers to optimise without compromise (ie missing out on the occasional hot shower)
@@karlajensen100 ok thanks for the reply. Maybe setting a timer for the HWS to top up for a half hour or so in the wee hours for morning showers whilst solar takes care of the evening usage could be the way to go with our small (160l) tank until we get a larger replacement HWS.
Another point to consider re failures with heat pumps relates to incorret installs & site location. A big study was just completed on this very topic, im sure it was done in Vic.
Interesting, I’ll look that up.
Here is the calculator! www.mcelectrical.com.au/electric-element-vs-heat-pump-calculator/
So ran the numbers. It’s cheaper for me to purchase a new istore (even before incentives included) then to keep my existing 2 year old system (zero purchase price and install) even with my solar and my controlled load of 12.5 cents. Can this be right?
How much hot water do you use?(kWh.) and what are you paying for power?
@@mcelectrical hot water represents about 1/3 of my energy bill (in terms of kWh usage). Family of 5, close to 300l a day. 15 kWh I assume.
@@twinrotors using 4 x less power and running daytime from your solar at the export rate of 8c, sounds like you're winning all round to me gofor it. with 300L daily demand it will run for around 5.25hrs a day. At that utilisation rate it should pay for itself in around 3.5years. It will obviously wear out faster and live for around 8 years, I'd suggest some lower flow shower heads in addition to maximise your savings (get them now and start saving today)
@@karlajensen100 what are the emissions for manufacture of istore?
Another great comparison debate. I love my iStore heat pump. It's been working every day for many years and as a relatively small power demand, and set to the solar preference cycle, it virtually runs off free solar every day.
Link to calculator broken. Link from the website blog is broken, too.
@21847835g thanks for the heads up, what error came up for you? Does this link work for you? mcelectrical.com.au/electric-element-vs-heat-pump-calculator/
Nope it doesn't work for me
15000 hours of operation = 625 full days of operation. What fraction of the day do these gadgets generally operate for ?
Very useful.
I have an electric tank that enters the heatpump tank then to house taps , I was going to swap it round and get heatpump to run first but had a thought to leave it as let the electric do most of the work so at least the pump will last longer
"if you've made your money three times over, you can just buy another one" yes, this is how all finances work..............
Exhausting the cool air outside doesn't seem like a good idea to me in any situation, the air that's exhausted needs to be replaced from somewhere...outside.
The cool air exhausted from the heat pump won't be as cold as the air outside. If it's below freezing outside that air will definitely be colder than the heat pumps exhaust.
Great video but can you get your units right on the graphics please? KWs are power. KWhs are energy. Thanks guys.
Yeh I noticed that after publishing! How embarrassing!
Has anybody done a comparison between heat pump v solar hot water system
My house faces north in Brisbane. What about a solar hot water system? How does that stack up overall? My 16 old Solar Hot water system has died.
We generally recommend replacing solar hot water systems with a solar panel system as often we can fit more panels on the roof in comparison to working around the footprint of a solar hot water system and that better provides the energy needed to heat your hot water, especially with a CatchPower: th-cam.com/video/-y9vuvjfNX4/w-d-xo.html Give us a call on 3268 3836 if you'd like more information.
10:42 based on your computation, you will save 200 bucks on a heat pump. But you have to replace the unit
Do heat pumps not need a solar timer or relay?
No! Istore have 2 timers built in!
This must surely skew the calculations in relation to wasted pwr when its a dull day with no solar input?@@mcelectrical
calculator link does not work?
Hi Andre, that's odd. Did you get a 404 page? It's working for us, but you could try the long link instead: mcelectrical.com.au/electric-element-vs-heat-pump-calculator/
In the UK, plumbers hate heat pumps because they make most of their money servicing gas combi boilers, charging 80 GBP an annual service. They can do the service in about 20 minutes so in a day, they can rattle through 15 services a day for very little effort making 1200 GBP a day !!!! ( Aus$ 2300 /day). With heat pumps in the UK at least, servicing is done by electricians with HVAC knowledge. The water based radiator system heating the home is rarely touched in any boiler service, so British plumbers are soon to have lower incomes and work harder for the rest of the work.
We live fully off grid and have a heat pump, free unlimited hot water 24hours no cost. Chinese heat pump cost $900 three years old. Family of four. Best decision we made going off grid.
At 12:02 for usage, that should be "kWh" not "kW" - listen carefully to your mate at 11:34.
Ohh, easy mistake. Sorry about that! Thanks for noticing :)
I'm in the market for a new HWS so looked at electric vs heat pump. I approached it from a different angle, ie payback period.
We will probably stay in our current house for the next 5-6 years so only interested in the short/medium term results. Also only interested in the bottom line $.
I have been quoted $2000 installed for a Dux electric and $4500, which includes rebates, for the Evo270 which seems very expensive. I have assumed approx $500 for each option for switchboard modifications.
With the current Alinta rates for Brisbane and 10% annual increase in the rates, with no solar installed, the payback period for the additional cost for the heat pump is 5-6 years. With 15% annual increase it is 4-5 years. So if you don't have solar and are going to be living in the same house long term it is probably a good idea to convert.
I have solar and a battery. Based on 8 months data from the smart meter, the solar would supply the electric system for 86% of the time and the heat pump system 93% of the time. To be conservative I used the 80% and 90% respectively that MCE used in their example. Using the actual figures makes the heat pump even less attractive.
The feed in tariff, Alinta's 8c/kWh for me, completely kills the economics of installing a solar supplied heat pump.
My current electric system is not connected to solar but supplied at the off peak rate. Average daily usage is 5kWh. The payback period for the switchboard modifications to convert to solar is approx 1 year, so seems like a no brainer to do so.
Subtracting the savings for solar supply to the electric system from the savings for solar supply to the heat pump gives a pay back period for the additional cost of the heat pump at 11-12 years.
From what I have read this is about the end of life for a heat pump so no point in doing it.
I also put the above figures into MCE's model and, if I remember correctly, the electric system came out about $1000 cheaper in running costs over 10 years than the heat pump.
I have double checked my spreadsheet calculations but if anyone can find an error I am happy to correct it.
Nice. Thanks for your comments. That’s kind of the point of the calculator. Everyone is in a different situation, has different motivations and different presuppositions. I feel generally, the heat pump is a winner. But definitely not always.
The heat pumps life expectation is normally determined by the # of compressor starts.
By simply changing the start/stop temperatures from 45/55C to 42/57C you can halve the starts and therefore massively extend the life expectancy.
(My NIBE ground source HP is 19y old and has only 64% of the expected # of compressor starts.)
A stock standard hws (= to a 12-to-16 kwH lithium battery) tied to my solar has been in place for 5 years and 0 problems.
Unlike next door's solar heat pump setup.
Solar feed-in rates are sH!t at present, so what diff does hws efficiency matter?!
Are you heating from 100 percent solar? Or are you sometimes buying grid power to heat your hot water? Definitely agree that some heat pumps have been terrible.
@@mcelectrical rarely, only have to use grid energy to heat hws a couple times in winter when not enough solar. Even then it is at the lower controlled load rates so not a big deal. A battery may have helped.
The heat pump installed in 2006 when I built my house needed replacing in 2021. I got a 13kw solar system in may this year ( thanks MCE -so far working better than your conservative estimates), now I just need to read the manual for the new heat pump so it only runs during the day when my solar is on.
Nice to hear Phill :) And yes, you are a good example of why plumbers and people like me hate(d) heat pumps. It might be time for us to move on….
@@mcelectrical why would we hate them with those numbers, is you calculator broken again ? 2021-2006 = 15 years! Phill has saved a fortune
Good luck with that. You will probably find you will run out of hot water if you do that.
That seems very cheap for a heat pump? - is that including a grant? - here in the UK you are looking at more than that price AFTER a £5k grant and then usually need to pay extra for radiator and pipework upgrades.
Yeh there is a rebate worked into those figures. I should have mentioned that.
Its only suitable for domestic hot water not hydronically heating a house. Here thats spectacularly expensive too
is that an actual power wall in the back round? Or just a shell? if it is a real power wall is it being used? Those things are like 8k in the US.. And yeah I went to a 50 gal rheem head pump water heater 2 years ago. I was on propane.. propane is really expensive we get it off of a "community tank" its like 3 dollars a gallon +. When I put this in instant 40 dollar a month saving. I also went from propane furnace to a heat pump one, and hundreds of dollars a month saving in the winter. Amazing how efficient this technology is when using electricity.
Ha, it’s just a shell. Tesla gave me a couple for my show room and my video room.
I have 10 kw of Solar 8.2 inverter. I have had the istore 270 2 years now. With the fronius app I can see around a 1kw load when heating.
I recommend istore . Seriously low energy bills. To be honest it hardly uses any power even at night
I'd be curious to know the duration of the 1kw pwr per day?
1 kw load per hour
Do you mean only 1hr per day?? Is it a one person home?@@virgin1958
Personally, I think the use case is very situational and the energy savings and cost savings can be depated. The heat pump tank will be extracting heat from the surrounding area and putting it in the tank.
So if you happen to live in an area where you heat your home half the year (like Canada) and your tank will just be extracting the heat you just generated to put it in the tank.
On the other hand, in those sotuations a heat pump clothes dryer, because they don't need an external air exhaust, will be a far better allocation of investment if looking for energy savings.
Kind of like Solar power systems, their value is very situational.
its an outdoor unit and heat pumps work in most climates. not many people live in extreme climates as its much easier to live in warmer places
Was trying to figure out why the heat pump would take heat from your home, and then realised that you probably have your hot water heater indoors.
Hot water units are mainly mounted outside the home in Australia (unless you live in an apartment). I could be wrong, but I think all the small apartment sized water heaters are element-heated and not heat pumps for exactly that reason. Where it would make sense for apartments is if they have a centralised hot water heater for the building, and that's where a commercial heat pump solution would REALLY save some money.
It is important to recognize that heat pump water heaters work better in hot climates. I live in a (very hot) summer climate. My garage gets very, very hot so the heat pump water heater is perfect for this location.
Sanjosemike (no longer in CA)
Yeh for sure. in Queensland, heat pumps are pretty efficient too.
Interesting discussion, but why is not direct solar included in the maths - mine has been operating for 20 troublefree years, not even sure if the tank heating element still works!
direct solar is also known as solar thermal - its typically good for a solid portion of the year in QLD but less than 8 months in Melb, they are typically more expensive to install and operate for the 200L daily use case that is a typical household. in Melbs thats 10kWh a day boosting for 120 days of winter , the pipe losses beat you up too if not close coupled system and installing tanks on roofs is $$$
For one considering a heat pump that makes sense, but, if solar thermal is allready in situ, its costs have long been absobed and its continued use should be considered when used with a heat pump. @@karlajensen100
I guess that would be a great topic for another video! I’m a electrician focused on solar, Karl works for a heat pump manufacturer. I probably should get a thermal hot water expert on!
A very interesting debate Mark. A couple of comments/ questions though. The Fronius Gen 24 Symo has a load management feature where you can do pretty much anything with loads. Rather that having the solar relay or other devices, wouldn't you just use the load management to drive a contactor and HWS? (I do this)
I like the idea of the heatpump HWS, only for energy conservation purposes (I think the environment is very important to save, but until to government takes it seriously without implementing knee jerking policies, I'll reserve my judgement) but I was badly burned to the tune of about 6K with a Rheem heatpump. As I found out later, the circulation pump had failed after about 24 months and it all got too hard to fix for some reason, so I threw it out and bought an electric storage tank.
That said, IF I was to get another heatpump HWS, doesn't it have to run considerably longer to make the water hot?
Why not a glass container be used instead of traditional steel
I'd love to see a comparison v Solar hot water, Heat pump and gas in perth. My 6.4 pv system averages 15kw+ per day in winter.
Secondly you can tell the "Victorian" is from the southern half of the state. A large area of the Nth gets 2 weeks more sun on average a year than the Gold Coast.
Ok, here is my environmental bias. If you are using gas, then it’s time you switched to a heat pump. But, it’s also always a long term economical win.
@@mcelectrical of Course, but how does a heat pump compare to Solar Hot water?
@@ZisWile easy - I'll take that an electric element based HWS does very little in Winter and you would boost it for 4 months a year, most of the solar benefit would be lost through the pipes if tank was on the ground as insulation R value is measured in decimal places. hence 10kWh a day for 120 days gives 1200kWh energy input that you need to find in the dead of winter , a heat pump uses 1200kWh a year in Perth. Istore sell IHEAT solar thermal systems in WA and they typically cost more to deliver less but people still want them so we still sell them. Perth is very good climate for solar hot water as their main foe is freezing the collectors whcih breaks them
@@karlajensen100 Thank you, My Solar thermal hws is currently 14 years old and on its second pump. Just planning what I move to next in that regard.
@@mcelectricalsustainability Victoria has a ROI on many H#S and the ROI on a HPHWS vs IGHWS is over 10 years
My question is more... Is it worth it to switch if you already have an existing instant heater...
Probably not. Unless you use an excessive amount of hot water and you pay a crazy amount for electricity. Just wait till it gets old and replace it. In saying that, I’m replacing my hot water for a heat pump soon. But that’s just cause I’m a nerd.
@@mcelectrical another thing also, since I live alone, would that basically bring down the efficiency of anything that has to use a water tank? Because I'd be heading up the whole tank for just one person?
What about heat recovery shower drains?
great idea YES , as Australia is otherwise a warm climate its typically too expensive hence hasnt seen mass adoption. Similarly with energy costing 5c/kWh from solar its easier and less expensive to simply get more panels and spend that cash on your electric car
@@karlajensen100 I'm surprised they cost much. A simple one should be just a cold water pipe going to the shower cold water tap that is inside the PVC drain pipe for few meters or so. Sounds like the current options are over engineered if they cost more than $200
@@PyjamasBeforeChrist a tradesperson in australia is $120/hr+ and i found this www.energy.gov/energysaver/drain-water-heat-recovery i note there is no way of accessing any of the pipes from any of my bathrooms however as they disappear into the slab it be assumed that the heat still ends up in the building envelope at least. Perhaps having a coil of pipe in the roof cavity to preheat the incoming water could also be of help?
Also to consider, is if you have a 5kw inverter and you have a heat pump that is running at 1.5kw, that's less solar energy in use to heat water and more solar available for other appliances at the same time. if your element hot water is running at 4kw, you only have 1kw remaining for your other stuff. Round numbers but you get the idea.
Yes! That is a huge point that I agree with. I cover that a bit in the blog linked to this.
The larger load could cause your invertor toast less time (ie it if it runs hotter). You can change the element to a smaller one to lessen the load, but then it runs longer....
@@mungewellyes that’s right. I replaced a 3600W element with a 1800W element so I could run my hw system longer through the day and reduce the load on the PV solar in case of cloudy weather our 10 kwh solar system can still heat our water on a timer switch. Another way I have used to reduce the power for a hw system element on a 24v bus setup, is to use a 5000w variable pwm and you can dial the power up or down to whatever ur solar is outputting.
I had 2 heat pumps. Both failed in 3 years (2007). Maybe they are better quality now.
the biggest issue is that most people will not have enough roof space to charge a resistive HW and one or maybe two EV's. this is where every space kw you produce from solar becomes important.
Yeh, I think as ev’s become more common, heat pumps will make more sense.
What about heat pump hot water vs natural gas? I live in the US and gas is much cheaper to heat water than electricity. Would a heat pump hot water tank be cheaper to use than a natural gas hot water tank?
Hi Mark, I guess it depends on the price you pay for gas an electricity. But I would imagine a heat pump would win, especially if coupled with solar.
@@mcelectrical Thank you!
These are great as long as you don't buy a cheap one. Excited about the technology, I bought a consumer-grade Rheem hybrid heat pump water heater in 2014 (from Home Depot) and it started throwing error messages after two years. No plumber within 100 miles has been willing/able to even attempt to repair it. I just switched to "electric only" mode and it's been operating that way ever since. Kind of a disappointment, but I still think the technology is good and worthwhile. I would be aware of the noise they make and look for a quieter unit if it's a concern (I could still hear mine in the house even though it was operating in the garage). Also, there's a chance that _I_ killed the heat pump with all the fine airborne sawdust I sometimes create in its vicinity. So that's possibly another thing to consider. But if you have the space for it (garage or basement, typically), I say you'd be nuts not to get one.
Yeh good point. Installing inside. Interesting! I guess at least you had the backup element.
Mark, surely a catch relay would be required with a heat pump too?
nope as effectively runs at 1000-1400W which is insignificant ~3.5kWh/day vs trying to find 10-12kWh and a much bigger 3.6kW load
@karlajensen100 $450 a year may be insignificant to you, but not to the majority of people, especially those who installed solar to save $$. Without any form of control any hot water system will use the majority of its power after the hot water has been used, usually in the evening after the sun has gone down.
It's got a timer built into the istore units you can program to heat during daylight hours
No, it can’t be used with a heat pump because you don’t want to regularly switch it. The Istore has 2 timers inbuilt.
Thanks all. FYI I did some testing recently, std 3.6kw hot water system, 2 people in Brisbane, 3.5-5.3kwh/day.only used for showers, turned power off we get 3 days of showers (last day temp was perfect without adding cold water) , 7kwh to reheat when turned back on
Having a refrigeration unit to make hot water is the most stupid idea! I should know we went through this nightmare because of basix requirements when we build our house a few years ago!
First ours run nonstop!
It was noisy!
It broke down at least once a month!
It is so complicated with a bunch of PCBs and other unreliable electronics!
They won't run if it get near 0 degrees.
The service technician who we came to know very well told me their a failed technology.
I disconnected it while still under warranty and took it to the tip. Bought a 400 litre duel element! It was luxury to have reliable hot water, and my power bill actually went down.
I still have nightmares coming home late after work to a cold shower!
@cdonuts7335 I’m surprised I haven’t had more comments like this. This was my opinion of heat pumps. How long ago did was it installed and what brand?
@@mcelectrical so am I reading through the comment section and look I'm not one to comment on these review videos but I developed such a disdain for these systems and cold showers. 😂 I couldn't help myself.
It was 10 years ago, it was a Rheem which at the time cost us a small fortune. I know you'll say they are better now but they are flawed like the technician said in the basic concept of using heat generated from condensing refrigerant to heat water. I also have friends and family that have or had heat pumps despite my advice recently and are having trouble.
I'm all for off-grid green energy! I've loved the idea of powering something by free energy from the sun since I was a kid! Been building off-grid systems since the late 80s.
But I see a lot of claims through this green energy push that in the real world just aren't true and don't work. While we "transition" to renewables those that aren't prepared may just have to get used to sitting in the dark while the grid load sheds and taking cold showers!
A heat pump for hot water sounds interesting ... but it'd be even more interesting if the output (cold air) could be used for cooling the house ... or if an AC already exists, why not use it to cool the roof space ?
Hmm, interesting. The cold air pumped out isn’t 11 degrees like an air con. I guess that’s the primary reason. The other reason is the amount of infrastructure to to this is untenable. At least it’s not off the shelf now. Maybe someone needs to work on a proof of concept and bring a product to market!
@@mcelectrical I had a chat to my AC Tech about this and he thought it'd be ugly but easy to run an "exhaust" from a heat pump into our ceiling space. Understand that it's not going to be 11°C but definitely cooler than the 80°C up there in summer.
Would have been better if you included instant gas - not tank - and homes with no solar .
Was this about Heat pumps or catch reloads
It was a comparison!
I consider a lifespan of 11-15 years as a poor outcome. I know we are in a throw away society now but if we care about preserving the earth’s resources large appliances should last more than 25 years. I bought my house 26 years ago and it had a Bosch gas instant hot water service, I still have it today and it costs very little to fuel.
What you missed out is that given that heat pumps use up to a 1/4 of the energy that a resistive element heater uses, that means they require 1/4 of the renewables capacity installed, which means less land, roof space etc used, less time to install said renewables capacity, less capital expenditure on infrastructure or home solar installation.
All that on top of the savings you calculated.
Kind of, but I wouldn’t put 1/4 the size of a solar system in just because you have a heat pump. Generally it’s best to fill the roof with solar panels regardless. This helps better cover morning and afternoon, winter and rainy days, and future proofs for an EV etc.
I wasn't suggesting putting in a solar system a 1/4 of the size.
I view choices made for heating, transport etc from the perspective of a nations total energy consumption as well as home owners individual consumption.
Heat pumps will have a big impact on a nations total energy consumption, along with ground transport electrification.
If those two changes were made, In most cases where the grid supplies most of the population, a nation could cut a 1/3 off it's energy consumption and reduce land used for energy production.
@@mcelectrical
my problem was the cost of the heat pump was WAY more, and i have solar, with the tank on a timer, I pay almost nothing for my hot water anyway.
I could not find a 250l stainless tank heatpump, and I refuse to touch VE tanks. staniless is going to last a hell of a lot longer than 15 years..
and yea, in Brissie. 6.35kw roof solar.
Yeh, I’ve heard different takes on that. I bought stainless for my place last time. Some say stainless is more likely to crack.
Stainless gets brittle with thermal and pressure cycling that a tank cops 500kPa is 72psi and 0-100 degrees, the welds crack.
Stainless tanks don't survive WA water more than 2 years and VE tanks still going.
Sanden stopped selling in WA for this reason It certainly stacks up economically in case of istore. if you can make the maths work for other solutions then thats great too
@@karlajensen100 I'd like some evidence for this.. and when exactly is your hot water system cooling down?
@@John-gm8ty Hot water systems cool down as you drain off hot water and cold water enters the tank. pressure goes from 0-72psi every time you turn the tap on and off. VE tanks have been used in Australia for over 50 years and the steel is not in contact with the water due to the coating. additional protection is offered by the anodes. The tank will outlive the heat pump hence as VE tanks are suitable for use with almost all levels of water quality in Australia they dominate the market. Further the way our rebates work, you dont get any if its a partial replacement vs an entire system hence replacement of separate parts is more expensive than a complete system,
@@karlajensen100 all I can do is face palm at your assertions and understandings.
also, almost NO ONE knows what an anode is, that they even exist in hot water tanks and that they must be replaces every 3-5 years depending on water quality and weather you have gal pipes with rust in them.
I have been posting on aussie forums for years explaining this to people and it's rare I ever fund people who know.
it's not even remotely common knowledge, my previous gas system didn't even have a damn access port to get to the anode, you had to completely disassemble the system to change it out. it was a Rheeme system too.
I guess if there is a thermal solar hot water system in place, and it is coupled with a heat pump and solar panels, you have the best of all worlds.
Sounds like a complex and expensive set up, but yeh preheating with solar sounds like a good idea in theory. I know a guy who did this simply by running the water through a coil of poly pipe on his roof. Bit of a hack job, but each to their own!
good debate what a shame Istore brand heat pumps are rubbish
I just replaced my element on a rhem hot water storage that is 23 years old, it's in great shape still, with a 50% life of the rod. Cost me $43 TO FIX IT.... I have 8kw solar on a timer 8.30 am till 10 am, if no sun it lasts 2 to 3 days for a shower no problems. Timer cost $75 on solar install. And no night tarrif meter. New system would have cost $1200 only. If there's no sun iturn thr heater off manually. Back on when it's out. I've saved many hundreds of $ just using common sense. Max my bill is $70 month from $700- 850 a qtr origin n energy
3 times more efficient, 5 times more expensive to install and buy. Not serviceable by home owner, 5 times more parts to manufacture. Have to look at the manufacturing impact on environment too.
Im not sure if you were quoted, but in Australia it’s not even close to 5 times more expensive to buy or install. Also, in Australia there is a rebate for heat pumps. I guess it would be difficult to calculate which is more environmentally friendly but a lot of energy is saved over 10 years with a heat pump.
The thing that generally gets overlooked in the "emissions accounting" is embodied energy. Everyone loves to talk about operational carbon but few people want to talk about embodied carbon. Which is understandable, because there isn't really any good embodied carbon accounting benchmarks and so people resort to making moterhood statements about perceived 'payback' of embodied carbon through reduced operational carbon during the life of the product.
From a homeowner perspective, they largely don't and won't know or care about embodied carbon. For them it's all about up front cost and operational cost. The embodied energy cost and end of life cost is out of sight, out of mind.... and we see that thinking play out time and time again with cheapie systems that fail prematurely but the comment is: "it's OK, it's paid for itself. I'll just throw it out and get another one".
There is no denying that the embodied energy of a heat pump (a two component system) is substantially higher than a resistive electric element tank (a one component system). And then further, at end of life (and all of the bits of these two types of hot water systems that need to be dealt with), the heat pump systems have got a refrigerant that needs dealing with.... and there's many heat pump hot water systems that employ refrigerants that are 1430 times worse than CO2 (R134a) and 2088 times worse than CO2 (R410a). And whilst Karl will always point out that refrigerants get recovered, I will always point out that the refrigerant recovery is nowhere near the level that all of the glossy promotions (and the regulations) suggest should be the case.
For the record: I am stongly of the position that domestic gas hot water heating (and all domestic gas appliances) should be outlawed for new homes, and where these appliances exist in our existing housing stock there should be encouragement (and subsidies) to help switch to electric appliances instead. I think that both heat pump hot water and resistive electric element hot water have got their place.... and I also think that solar hot water (not discussed here) also has its place. The important thing is that the systems are of high quality, high efficiency, well installed, well cared and well maintained. And then the final piece of the puzzle is that the hot water usage needs to be addressed. If a 'typical household' of 4 people is using 200 litres of hot water per day, then I'll argue that 'typical household' has got hot water usage problems that should be addressed.
🙂
Great point. We did talk about embodied energy, but I thought it was getting to complex in the video. Especially that we assumed the tank will last as long, so you can use a heat pump as a electric tank when the heat pump fails. My assumption was that the amount of energy saved will vastly outweigh the embodied energy. But maybe I’m wrong on that assumption.
@@mcelectrical - lots of people are making assumptions about embodied energy, which is quite reasonable and understandable because the 'accounting' is very flakey. So, you've got to make guesses.
But a semi-technical person is able to appreciate how much extra infrastructure goes into manufacturing a heat pump compressor unit, as opposed to just the hot water tank alone. All of the different components that get manufactured in different factories and shipped around to where they ultimately get assembled into the heat pump compressor unit.... there's a lot of "stuff" in there!
And in regards to payback of embodied energy, I'll argue that a bulk hot water tank should STILL last 25 years... provided that the home owner keeps up with the very basics of anode checks / replacement. The reason for premature failure of a bulk hot water tank (other than bad installations) is lack of simple maintenance.
Totally agree. "it's OK, it's paid for itself. I'll just throw it out and get another one". This highlights the exact issue with our current society and way of life. Drives me nuts. Unfortunately everything is about economies of scale/global trade on cheap energy. Until society understands that there is no economy without smart efficient use of energy our problem is only going to get worse.