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The outer cladding is wood fibre panelling by Steico. It is coated with a natural Lime render

Thats a great idea. I will do some 'meet the builder'' videos

Yes! Thank you!

We don't build from brick so it it is hard to do a side by side comparison with a similar project. Construction to this standard does use more costly materials and it is more labour intensive to install membranes, insulation compared to just slapping up some brick and rendering it. At a guess I would say +20% more

It really depends. When you engage a professional you are paying for their time. If you want something fully bespoke, that takes longer to design and document so you could expect to pay 10-12% of the build cost. For a smaller low budget home it makes more sense to work from something pre-designed. Work with someone who already has a suitable design fully resolved that they can modify to your requirements. We have done this for clients for around 4-5% of build cost.

Check the Passive House Association for certified tradesmen / builders in your area. Have a good look at their completed projects but most importantly choose a designer who know how to build cost effectively!

no cap

did you have to watch this video for an investigation aswell?

Very true! Although for practical reasons we don't see too many round houses

Thanks!

Here in Australia we had a product called an Odyssey whole of house fan that did just that. It could purge a whole house very quickly and could be retrofitted to an existing home that is not necessarily built to be airtight. I don't think it sold to well because it no longer seems available. Here is the brochure www.bradfordventilation.com.au/-/media/edmonds/files/odyssey-brochure.pdf

We specify a special mix of concrete that is then professionally sanded and sealed for a smooth hard wearing finish.

Sounds great. Keep an eye on our website as you will soon be able to purchase plans for small passive house designs to build.

@@theleanarchitect Hi, What are your thoughts on SIPS - I've been researching this recently and it looks a good option, for my eventual design, that I'd only like to be about 37sq m, for a one bedroom, on a polished concrete floor home, passive design. There is a company in Daylesford, VIC manufacturing SIPS but there are many companies I think manufacturing SIPS across Australia. Anthony (Kaikohe, Northland, NZ - SAT 07 SEP 2024, 11.15 a.m.)

We have an in depth article about SIPS on our website. leanhaus.com.au

Simply reducing the scope, specification and complexity of cabinetry is one of the easiest ways to save. Cabinetry is a subject in itself. I am trying to highlight to clients that it is ok to rationalise the scope of cabinets if it helps you to afford a Passive House!

Additional overhangs and eaves would have added significant cost and provide limited benefit against low angle morning (east) and afternoon sun (west). The main benefit of blinds is that they are operable. They only need to be closed when the sun is directly hitting the glass.

@@theleanarchitect I love the metal exterior. Beautiful home you have.

180mm of High Density Glass Wool - System U value 0.23W/(m2K)

@@theleanarchitect thank you!

Thermal Mass is not a consideration of Passive House Software. The thermal stabilising effect of the concrete slab is not quantified but I believe it would be of some benefit in summer. However in winter you pay a heavy penalty for heat losses through the slab to the ground.

@@theleanarchitect that’s surprising, I would have thought in hot climates even more important. I was an architect, we did a house for an engineer, had solid concrete floors and concrete cored walls, he calculated it would hold six months of heat. ps. You always insulate below the slab in cold climates

Where is the house you're referring to? I'm guessing northern hemisphere based on you saying it's summer and it's August. Is it an actual certified 'PassivHaus', rather than 'passive solar designed'? I guess the challenge relative to health is should we sleep at a natural room temperature of 24C, perhaps with a fan on, or use conditioned air and sleep at 18C?

Thermal comfort is entirely subjective. That said, 24 degrees is considered within the human comfort zone and the design parameters of passive house. Your expectation for 17-19 degrees night temps in a warming climate is unrealistic and reliant on the use of AC at a time of day when there is no renewable energy generation. If we actually want to live sustainably, people will have to adjust their expectations around climate control.

I'd love to have 24° C all day long!!!

Have you tried something as simple as opening all the windows early when the air is cold, then closing them when the house cools and before it gets hot outside, and when the air gets stale, strategically opening a first floor window on a shaded and cool part of the outside, and open another window one the second floor, if in a two storey home or a 1st floor windows on opposite ends, to get fresh cool inflow?

@@boxerfencer that is a great idea

We do have an openable window. However the ventilation system does a great job of drying out the room leaving it odour free with dry towels and surfaces.

The building has a mechanical heat recovery ventilation system that runs 24/7 and moves the entire volume of the house in 3 hours. It does not purge heat as quickly as open windows, so when we have cooling breezes we purge the heat. The point is that if you add coolness to the house via AC then t does not escape to the outside easily.

@@theleanarchitect great piece of advice.

All the windows have flyscreens. Screens on the French doors are optional. Given its usually much more comfortable inside than out, we find that doors usual stay closed.

Thankyou!

Yes and its going to get hotter!

I disagree that Passive House is a cold climate system. Yes it was developed in Germany, but they can also have warm summers up to 30c. PH is a comfort, health and energy efficiency standard than can apply to all climates. The same envelope that keeps warmth in can also keep heat out, and be easier to keep cool. Adding coolness is easier and cheaper than adding warmth, because the sun is shining and generating cheap solar power precisely when you want to run the AC. The comfort in a PH is achieved by maintaining a temperature and humidity level within the comfort zone (18-25c / 40-60% Relative Humidity) We find that our Relative Humidity inside our home is consistently 50% because the HRV is actively removing surplus moisture rom bathrooms and kitchens. Humid climates adopt a slightly different airtight construction methodology (with the membrane on the outside - to keep humidity out) and utilise ERVs which are specifically designed to extract moisture from humid air.

Passive house is about energy efficiency and air tightness. It is not specified for a particular climate. Air conditioned spaces benefit from insulation if out door Temps are hot. Think of a cooler for camping etc. Energy recover ventilator is used to deal with fresh air . And you can use decives to control humidity.

Thanks for sharing your research! We surface measured light and dark metal cladding in full sunlight and found only a small difference of around 6c or less than 10%. Not terribly scientific but interesting nonetheless. It would be interesting to put sensors inside the two wall options and measure the phase shift in real time.

@@theleanarchitect There are so many subtle differences and I'm not sure how much it all affects the end user. Good old passive solar design is the absolute go to as a starting point. The less machines and moving parts the better. One interesting thing I measured today was the heat of a concrete floor slab inside sliding double glazed doors. The doors were closed. Where there was no fly screen the slab measured 32.1C, where the crimsafe fly screen was in front of the glass the slab measured 25.9C. Outside temp 25C. How that affects the comfort of the house this evening is probably negligible! But interesting nonetheless.

This video is not intended for owner builders. I would not recommend a Passive House type solution as an owner builder project unless you come with significant experience and expertise. It will take longer, cost more and may not have the desired outcome.

Hi @martiruda, we’re looking to be owner builder for our build. Would you mind sharing more about your owner builder experience?

Could you please link the custom cabinetry for me?

25 degrees at 45% relative humidity is well within the human comfort zone. Add air movement from a ceiling fan and it feels more like 23c.

We have not had any issues with dust in the ceiling. Dust levels are definitely lower than on a normal house being that the house spends more time sealed up and the HRV filters out airborne particles.

That is warm! Regardless of the climate, a well insulated and sealed home will be easier to cool with AC.

That's the temperature we choose to set. Other clients go for less, and some choose no AC at all!

Thanks! Well done noticing the fascia and capping. Its the small things that elevate a building. Its th result of great work and collaboration by our builder and roofing trade.

Amazing to build so much for so little. Well done!

Everyone has different comfort requirements! Cooling a house to below 20 degrees when its 40+ outside will use a lot more energy than 24 degrees.

😂 And you step out and die by a heart attack in those 40°C...

Meanwhile he's on wife #3, paying 3 alimonies to keep his AC bill down. 🤣

Thank you! Will do!

It is a possibility. We are looking at opening an office in SF to service the west coast. Please send an enquiry via Leanhaus.com.au

Solar hot water often requires electric or gas booster. A heat pump HWU is more efficient and is powered by our solar PV anyway.

Like all other houses 🏘️

😂

I agree that the openings at the top and the bottom of the cladding may not ventilate all the heat trapped by the cladding. But it is better than no cavity. In this case we made a conscious decision to go with a dark cladding and the performance of the home doesn't seem to suffer as a result.

@@theleanarchitect Thanks for the reply. I can see how it would be tempting to use a concept like that to counteract the disproportionate emphasis you Ozzies put on cladding colours. But if the effect represents like <1% of the total heat transfer, it just contributes to the confusion and doesn't help towards developing good practices. Our equivalent discourse are green roofs in the UK!

The colour does affect the local microclimate, however on the Midnorth Coast of NSW walking next to a white steel wall is much more uncomfortable due to the sun reflecting off it. It's amazing how intense the heat being reflected is. The dark steel reflects the heat too, but not as intensely. I'm sure this would be similar in many parts of WA. If the walls are masonry that would change the scenario. I'm really keen to see studies on the urban heat island effect with a comparison between steel and masonry roof types. I believe there's some study at Newcastle Uni in to this.

​@@FrankReifoh that's interesting - what's the misunderstanding around green roofs?

@@theowhite They're expensive to build, heavy, impractical to maintain, and are just worse than using the equivalent price for much more insulation. You're better off going for a standing seam steel roof, vented mesh to the ridge. It'll last 50 years with next to no maintenance, no problem. PV systems mount very well to the seams. And you can have it in any colour you like, if you're in an AC climate, by all means make it white!

Interesting suggestions. Often the cost premium for deviating from a local standard solution makes innovation difficult to achieve. I would love to use the waste cold air from the pool and hot water heat pump to cool the house, but no such integrated mechanical solution exists. So we are stuck with a separate AC, HWU and Pool heater. Good for redundancy but not great for efficiency - although the solar PV is very effective at powering these at no cost for us during the day. BTW, we heat our pool to around 25-28 degrees in summer.

Walls are R5, Roof r6.

@@theleanarchitect similar to our house KFW55 in Germany. KFW55 means the house consumes 55% of the energy the given reference house (conventional new build house) consumes. Standards are regulated by the GEG law and other norming rules in Germany: U-values (W/m2 k) of our house: roof 0.17, walls 0.23, floor 0.15, shaded balcony 0.15, windows 0.76, entrance door 0.76. (U=1/R)