Hi Matt, Awesome video! I’m a 50 year veteran of the HVAC industry as well as an instructor of manual J and D. Over the last 30 years as a major brand service manager I’ve witnessed so many horrible installs in the new construction industry with the builder only caring about the cost. Your view on quality is so refreshing and so very timely. My fervent best wishes for your continued success and of building a loyal following. Best, Wayne Schneyer
Appreciate you commenting! That photo is from a house I built a few years ago. At that time code for our climate zone only required 5.5" of SPF in the rafter bays. It's unlikely in Texas that you would have condensation form on the studs due to cold outside. However, since that photo was taken I've moved to 8" standard depth for open cell SPF in the attics I build which gives nice coverage over the 2x6 rafters I commonly use. I also try to build with 2" of foam on top of the roof deck. Matt
Great point about running these in a typical vented attic! Thanks for commenting! I've heard great things about Daikin but only used Mitsubishi to date for VRF units. What was your impression of Daikin in working for them? Appreciate your excellent comment. Best, Matt
Nice video Matt. Back in 2006 I worked for Daikin when they first were getting going in the USA giving builders a very similar presentation. It's nice to see builders finally combining high performance construction with inverter technology. One thing is to NEVER use any of these ducted air handlers (Mitsubishi,LG etc.) in a vented attic. They are very leaky and the fans run 24/7 resulting in huge amounts of duct leakage. I know you don't do vented attics, but wanted others to know.
Yes the UA105 does add heat load inside the house, but that penalty is well worth it! This new SD12 from UltraAire is a split dehum so the heat goes outside to the condenser and it provides a small degree of cooling along with dehumidification. It's alot like an AC unit that's optimized for dehumidification (latent) rather than cooling (sensible) as an air conditioner does mostly. I've got a video and blog post in the works. I'll have the post on my blog soon.
Yes us HVAC geeks need to stick together! We are the ones that will sway the masses towards better systems. They "think" they don't care about HVAC but once they live in a house with a Good system they won't ever go back! Appreciate you watching AND commenting. Best, Matt Risinger
Very informative video Matt!! I really enjoy watching your videos, especially these HVAC related ones! I like keeping up with the new up and coming technology in HVAC design and application. The future is looking better all the time with the Variable capacity systems coming into the picture. I'm glad to know that they are making them with more conventional indoor components so ducting can be used to serve more rooms with one air handler. Thanks for the great video! I guess I'm a geek too..lol!
Thanks for these videos! You showed a picture of a spray foamed attic. Is there a reason the rafters weren't completely covered? I would think water could condense on them on a cold day. Am I missing something?
how do you feel about rigid duct supplies containing an insulated liner within them? this "liner" in my supply duct is actually comprised of several smaller pieces cut to fit. in doing some diy improvements i noticed inside a few of these liner pieces had come off the walls and ceiling of the duct, and was blocking air! i could see all the fibers flying off when i tried to reseat these pieces into place (they're not even glued to the interior walls). this supply line is located in my garage ceiling, so it's basically unconditioned space and absolutely exposed to such when the garage door is open. thanks.
Very interested in watching a video on the SD12 that u spoke of. Dehumidification without the penalty of sensible heat gain. Products like the 105H just make sense but being they add a small amount of sensible load my HVAC would have to move outside leaves a bitter taste in my mouth. Maybe I have that wrong but any dehumidifier I've used produces a fair amount of heat.
Interested to hear your thoughts on the Trane XV Systems. Also noted your use of a 95% efficient furnace. Is that really a huge deal over a 80% system in the south where we use it so infrequently? In Dallas, TX as a point of reference.
I'm not familiar with the Trane XV system. Is that a variable capacity AC? The big deal on 95% efficient furnaces is that they can be vented with PVC. I like that because I can put one in an un-vented attic and not worry about combustion air. Then I can easily air seal the PVC pipes through the envelope. With 80% furnaces you have a hot metal vent going through the envelope and it's hard to seal them, plus you have combustion safety issues. The minimal increase in price to the 95%+ units is definitely worth it. Best, Matt
A 95% efficient furnace is a waste of money in Houston, TX and further south. It does get colder in Dallas but I still don't know if I would install a high efficiency furnace there either. The high efficiency furnaces just aren't as reliable due to complexity but they do makes sense up North where the winters are very bitter and the furnace has to run more often and the efficiency makes up for the cost of natural gas. Expensive, complex furnaces with fancy DC motors cost a lot of money to repair so get a good warranty with an established company. I have relatives in Ohio that are running 45 year old gas furnaces and don't want to upgrade because those old furnaces are simple and reliable.
The main difference is the ability to serve multiple independent interior zones from a single outdoor unit. The Trane system is only 1:1. Also, overall energy use and outdoor unit sound pressures are typically lower for the multi zone VRF Systems. Thanks for watching and commenting! Matt
Thank you for the presentation, Mr. Risinger. The embedded link to your video on Scott Gander (of Dick Clark and Associates) house HVAC setup is not working. Can you please fix it. We are considering using a Mitsubishi MVZ paired with an outdoor heat pump as an alternative to a gas furnace and air conditioner combination in our new house and would love to learn more.
Excellent video ,I live in Tampa FL and I have a flat roof with mansards in most of my house, its U shaped with a cathedral ceiling joining the two flat side and no attic above. The flat roof on the mansards have about 4 foot high with a small crawl space between the 2. I was wondering would it be better to use foam as it is a small space or blown in cellulose of fiberglass? Also what ultra air unit or units should I use as I have 2 AC's at 3 tons each thanks Andy:)
Andy, Thanks for commenting. If you can get your ducts inside the AC space that's best. I like foam because I can spray it to the roof deck and create a conditioned space for my ducts to run inside. However, if this is a retrofit job it's going to be tight to get into a 2' tall space and spray foam. Regarding the Dehum's your house would most likely be served with one unit for the whole house. Humidity equalized around your house unlike temperature. A degum attached to one of your three ton HVAC units would service the entire house. I'd consult the Ultra-Aire website for sizing. Most likely one XT105 would service your house but you might need to go to the next larger size. Best, Matt
Hello, I've been viewing your videos and am really enjoying the insight you offer. This may be a "dumb question" ....but what exactly do you mean when stating the unit is in a conditioned space? I know this entails the attic as seen here. Does this mean the ceiling joists are not insulated? I've gleaned the spray foam in the rafters, but if the ceiling joists are insulated as well, wouldn't that just put the unit in an insulated space? If the attic is totally insulated, does the unit have a register in the space to help condition it? And am I right to assume there is no venting of the attic to the outside? I am about to build a home in NC and have become infatuated with the info you offer in these videos. Thank you for making them. All the best to you. Ron
Matt, I've been advised by several HVAC contractors that with a variable speed unit a stand alone dehumidifier is unnecessary. I'm in the rough in phase right now and we did not include a dehumidifier in the estimate. Im in south Louisiana and will be using foam insulation and creating a conditioned attic. I'm using electric HVAC units. Would love to hear your thoughts. Thanks!
Christopher, It is true that a two-stage compressor will do a better job at humidity control than a single stage, but in my opinion adding a Dehum will add a huge amount of comfort to your house. The ability to dehumidify apart from your thermostat is a big help in the spring & fall, and it allows you to set a higher T-stat set temp and still be comfortable. I install an Ultra-Aire Dehum in every house I build. Best, Matt
Chris, They don't have representation in my market, but I would think they make excellent products in this category too. As a brand, I have nothing but high trust for that company. I use their bath fans exclusively, and their heat pumps are in the "guts" of the heat pump water heater I like. Hopefully they will expand to my market. Best, Matt
Daikin makes a good product but parts are really expensive. I ended up going with Mitsubishi 4-Port units (not city multi) using a combination of ducted and ductless air handlers in my new home. Incredible comfort, efficiency and humidity control.
I presume that passive house are not supposed to be equipped with ventilated range hood. Since its exhaust rate can easily exceed supply rate from lots of equipment. Is my presumption correct?
If the spray job gets muffed, you will be taking the entire roof off to fix. If the fresh air returns get blocked, it better have a shut off system. If you insulate so much, why not just size down the ac till it runs enough for dehumidification? If the house is too right, now its your job to keep up the exchange system. There may be a reason why homes have been built with ventilated attics and simple insulation, less systems to maintain and equipment runs enough to dehumidify and air exchange gets thrown in too. Just keep your soffit vents free of blockage.
have a new unit but does not cool down past 77 looked up there has 2 PVC pipes blowing out cold air, one I think is for condensation or water flow out, the other one right next to it. just open, blowing cold air in attic should this be capped off?
If IT IS 3/4 OR 1 inch pvc it should have a trap . but should not affect the temperature that much. On a hundred degree day the design temp may be only 89 degrees with 75 degree indoor temp. That is why I like someone else to design the system .. In the north east our summers are short . And we only get a three week heat wave .I only say don't wait until you get home to turn it on when the house is 90 degrees . It won't recover and if it does then it is way over sized .They pay a lot of money for an ac system and when it is hot who wants to hear about design temps.
Now that Trane/American Standard (XV18 and Platinum 18)and Lennox (XP20/25) have joined the ranks of VRF, have you had any hands on experience with those units? Hopefully they will provide MUCH needed competition in that market space. The big mini split/ VRF players really need a push to drive down their crazy prices.
gracilism , just buy them internationally. Rest of the world has been using them for decades. Ridiculous what they charge here for standard equipment t in the Rest of the world.
Hi, Mat, So, I'm confused. I'm going to build a 2000 sq ft home in Corpus Christi (Island), and I really like the Mitsubishi product. Will I also need to install a dehumidifier?
Very informative. Thank you. I'm in Alabama and going to be building a new house soon and am sold on minisplit systems. However, installation costs of these things seem quite exorbitant for such an easy installation. A system I could purchase for 5k (4 zones) online will cost me 7k from a local contractor then 5 to 7k for installation--for units that I could ALMOST install myself. Can you help me understand why contractors would charge so much for what should be a very straightforward installation?
Jim Fisher Jim, I wouldn't attempt to install a multi-zone VRF system yourself. Your contractor would need to attend a 2-3 day training from the manufacturer to be certified to install these then typically has a factory rep commission his first few installs. They look "easy" on the surface but they are actually quite complicated and small errors can lead to problems. Those prices seem pretty standard to me. That HVAC sub isn't getting rich on that install. I wish you the best. Matt
For that price you could get a split system heat pump installed at maybe 500 - 600 sq/ft per ton and have a great system. I work on mini - splits every day. Yes the technology of mini - splits is more advanced than split systems at the equipment level however, there will always be a bulky box mounted on your wall and without a duct system it is impossible to match a properly installed split system AC with regard to comfort.
I have wondered for a long time about the dehumidifier in Texas. I am in Corpus Christi and humidity is even more a problem for us than Austin. have you encountered any science relative to efficiency of the dehumidifier? The whole thing boils down to education for the consumer which you are doing a fine job of.
95% efficient gas furnaces waste $5.00 worth of gas per $100. of gas purchased. 80% efficient gas furnaces waste $20. worth of gas per $100. of gas purchased. It gets cold in the South 1.5 - 2 months per year. My natural gas bill has never been over $30. As for humidity, proper heat load calculations will suffice for humidity control. "All air conditioners are dehumidifiers". A single stage heat pump which is sized properly for the load will do the job; a two stage heat pump will control humidity more accurately.
Hi Matt,
Awesome video!
I’m a 50 year veteran of the HVAC industry as well as an instructor of manual J and D. Over the last 30 years as a major brand service manager I’ve witnessed so many horrible installs in the new construction industry with the builder only caring about the cost.
Your view on quality is so refreshing and so very timely.
My fervent best wishes for your continued success and of building a loyal following.
Best,
Wayne Schneyer
Appreciate you commenting! That photo is from a house I built a few years ago. At that time code for our climate zone only required 5.5" of SPF in the rafter bays. It's unlikely in Texas that you would have condensation form on the studs due to cold outside. However, since that photo was taken I've moved to 8" standard depth for open cell SPF in the attics I build which gives nice coverage over the 2x6 rafters I commonly use. I also try to build with 2" of foam on top of the roof deck. Matt
Thanks David! Appreciate your kind comments and taking the time to watch my video blogs! Best Matt
Excellent info and spot on in my opinion.
This is a great video.
Great point about running these in a typical vented attic! Thanks for commenting! I've heard great things about Daikin but only used Mitsubishi to date for VRF units. What was your impression of Daikin in working for them? Appreciate your excellent comment. Best, Matt
Nice video Matt. Back in 2006 I worked for Daikin when they first were getting going in the USA giving builders a very similar presentation. It's nice to see builders finally combining high performance construction with inverter technology. One thing is to NEVER use any of these ducted air handlers (Mitsubishi,LG etc.) in a vented attic. They are very leaky and the fans run 24/7 resulting in huge amounts of duct leakage. I know you don't do vented attics, but wanted others to know.
Yes the UA105 does add heat load inside the house, but that penalty is well worth it! This new SD12 from UltraAire is a split dehum so the heat goes outside to the condenser and it provides a small degree of cooling along with dehumidification. It's alot like an AC unit that's optimized for dehumidification (latent) rather than cooling (sensible) as an air conditioner does mostly. I've got a video and blog post in the works. I'll have the post on my blog soon.
Great video as always. Very informative and easy to understand. I enjoy your video blogs, keep up the good work.
Yes us HVAC geeks need to stick together! We are the ones that will sway the masses towards better systems. They "think" they don't care about HVAC but once they live in a house with a Good system they won't ever go back! Appreciate you watching AND commenting. Best, Matt Risinger
Very informative video Matt!! I really enjoy watching your videos, especially these HVAC related ones! I like keeping up with the new up and coming technology in HVAC design and application. The future is looking better all the time with the Variable capacity systems coming into the picture. I'm glad to know that they are making them with more conventional indoor components so ducting can be used to serve more rooms with one air handler. Thanks for the great video! I guess I'm a geek too..lol!
Thanks for these videos! You showed a picture of a spray foamed attic. Is there a reason the rafters weren't completely covered? I would think water could condense on them on a cold day. Am I missing something?
I have not heard of them, I'll have to look them up. Matt
how do you feel about rigid duct supplies containing an insulated liner within them? this "liner" in my supply duct is actually comprised of several smaller pieces cut to fit. in doing some diy improvements i noticed inside a few of these liner pieces had come off the walls and ceiling of the duct, and was blocking air! i could see all the fibers flying off when i tried to reseat these pieces into place (they're not even glued to the interior walls). this supply line is located in my garage ceiling, so it's basically unconditioned space and absolutely exposed to such when the garage door is open. thanks.
Justin Wittock Not a fan... Exterior insulated metal is the way to go...
Very interested in watching a video on the SD12 that u spoke of. Dehumidification without the penalty of sensible heat gain.
Products like the 105H just make sense but being they add a small amount of sensible load my HVAC would have to move outside leaves a bitter taste in my mouth. Maybe I have that wrong but any dehumidifier I've used produces a fair amount of heat.
Interested to hear your thoughts on the Trane XV Systems. Also noted your use of a 95% efficient furnace. Is that really a huge deal over a 80% system in the south where we use it so infrequently? In Dallas, TX as a point of reference.
I'm not familiar with the Trane XV system. Is that a variable capacity AC? The big deal on 95% efficient furnaces is that they can be vented with PVC. I like that because I can put one in an un-vented attic and not worry about combustion air. Then I can easily air seal the PVC pipes through the envelope. With 80% furnaces you have a hot metal vent going through the envelope and it's hard to seal them, plus you have combustion safety issues. The minimal increase in price to the 95%+ units is definitely worth it. Best, Matt
A 95% efficient furnace is a waste of money in Houston, TX and further south. It does get colder in Dallas but I still don't know if I would install a high efficiency furnace there either. The high efficiency furnaces just aren't as reliable due to complexity but they do makes sense up North where the winters are very bitter and the furnace has to run more often and the efficiency makes up for the cost of natural gas. Expensive, complex furnaces with fancy DC motors cost a lot of money to repair so get a good warranty with an established company. I have relatives in Ohio that are running 45 year old gas furnaces and don't want to upgrade because those old furnaces are simple and reliable.
What is the main difference for a residential home on a VRF vs a Trane XV20i series that is also completely variable?
The main difference is the ability to serve multiple independent interior zones from a single outdoor unit. The Trane system is only 1:1.
Also, overall energy use and outdoor unit sound pressures are typically lower for the multi zone VRF Systems.
Thanks for watching and commenting! Matt
Thank you for the presentation, Mr. Risinger. The embedded link to your video on Scott Gander (of Dick Clark and Associates) house HVAC setup is not working. Can you please fix it. We are considering using a Mitsubishi MVZ paired with an outdoor heat pump as an alternative to a gas furnace and air conditioner combination in our new house and would love to learn more.
Excellent video ,I live in Tampa FL and I have a flat roof with mansards in most of my house, its U shaped with a cathedral ceiling joining the two flat side and no attic above. The flat roof on the mansards have about 4 foot high with a small crawl space between the 2. I was wondering would it be better to use foam as it is a small space or blown in cellulose of fiberglass? Also what ultra air unit or units should I use as I have 2 AC's at 3 tons each thanks Andy:)
Andy, Thanks for commenting. If you can get your ducts inside the AC space that's best. I like foam because I can spray it to the roof deck and create a conditioned space for my ducts to run inside. However, if this is a retrofit job it's going to be tight to get into a 2' tall space and spray foam.
Regarding the Dehum's your house would most likely be served with one unit for the whole house. Humidity equalized around your house unlike temperature. A degum attached to one of your three ton HVAC units would service the entire house. I'd consult the Ultra-Aire website for sizing. Most likely one XT105 would service your house but you might need to go to the next larger size. Best, Matt
Matt Risinger thanks for the info Matt I will call ultra -air
Just curious why couldn't PVC pipe be used for duct work? Can't it be sealed air tight very easily?
Wendell Satterwhite , they do
my interest on youtube always lead me to a Matt Risinger video! I went with the Daikin Furnace 97% AFUE. Looking into the ultra-aire products.
Hello, I've been viewing your videos and am really enjoying the insight you offer. This may be a "dumb question" ....but what exactly do you mean when stating the unit is in a conditioned space? I know this entails the attic as seen here. Does this mean the ceiling joists are not insulated? I've gleaned the spray foam in the rafters, but if the ceiling joists are insulated as well, wouldn't that just put the unit in an insulated space? If the attic is totally insulated, does the unit have a register in the space to help condition it? And am I right to assume there is no venting of the attic to the outside? I am about to build a home in NC and have become infatuated with the info you offer in these videos. Thank you for making them. All the best to you. Ron
Matt, I've been advised by several HVAC contractors that with a variable speed unit a stand alone dehumidifier is unnecessary. I'm in the rough in phase right now and we did not include a dehumidifier in the estimate. Im in south Louisiana and will be using foam insulation and creating a conditioned attic. I'm using electric HVAC units. Would love to hear your thoughts. Thanks!
Christopher, It is true that a two-stage compressor will do a better job at humidity control than a single stage, but in my opinion adding a Dehum will add a huge amount of comfort to your house. The ability to dehumidify apart from your thermostat is a big help in the spring & fall, and it allows you to set a higher T-stat set temp and still be comfortable. I install an Ultra-Aire Dehum in every house I build. Best, Matt
Thanks so much for the response and the information! I look forward to future videos!
Question? What are your thoughts on a duel fuel system. Ex. 97% 2 stage gas with 20 seer 2 stage heat pump. Thanks.
matt what do you think of the panasonic vrf hvac systems.. we always here about lg or mitsubishi
Chris, They don't have representation in my market, but I would think they make excellent products in this category too. As a brand, I have nothing but high trust for that company. I use their bath fans exclusively, and their heat pumps are in the "guts" of the heat pump water heater I like. Hopefully they will expand to my market. Best, Matt
Daikin makes a good product but parts are really expensive. I ended up going with Mitsubishi 4-Port units (not city multi) using a combination of ducted and ductless air handlers in my new home. Incredible comfort, efficiency and humidity control.
I presume that passive house are not supposed to be equipped with ventilated range hood. Since its exhaust rate can easily exceed supply rate from lots of equipment. Is my presumption correct?
Max Young ,you have air exchangers.
If the spray job gets muffed, you will be taking the entire roof off to fix. If the fresh air returns get blocked, it better have a shut off system. If you insulate so much, why not just size down the ac till it runs enough for dehumidification? If the house is too right, now its your job to keep up the exchange system. There may be a reason why homes have been built with ventilated attics and simple insulation, less systems to maintain and equipment runs enough to dehumidify and air exchange gets thrown in too. Just keep your soffit vents free of blockage.
have a new unit but does not cool down past 77 looked up there has 2 PVC pipes blowing out cold air, one I think is for condensation or water flow out, the other one right next to it. just open, blowing cold air in attic should this be capped off?
If IT IS 3/4 OR 1 inch pvc it should have a trap . but should not affect the temperature that much. On a hundred degree day the design temp may be only 89 degrees with 75 degree indoor temp. That is why I like someone else to design the system .. In the north east our summers are short . And we only get a three week heat wave .I only say don't wait until you get home to turn it on when the house is 90 degrees . It won't recover and if it does then it is way over sized .They pay a lot of money for an ac system and when it is hot who wants to hear about design temps.
Excellent
Thanks! Best, Matt
Now that Trane/American Standard (XV18 and Platinum 18)and Lennox (XP20/25) have joined the ranks of VRF, have you had any hands on experience with those units? Hopefully they will provide MUCH needed competition in that market space. The big mini split/ VRF players really need a push to drive down their crazy prices.
gracilism , just buy them internationally. Rest of the world has been using them for decades. Ridiculous what they charge here for standard equipment t in the Rest of the world.
Can you recommend someone in East Tennessee that does the foam in attics?
Hi, Mat,
So, I'm confused. I'm going to build a 2000 sq ft home in Corpus Christi (Island), and I really like the Mitsubishi product. Will I also need to install a dehumidifier?
Very informative. Thank you. I'm in Alabama and going to be building a new house soon and am sold on minisplit systems. However, installation costs of these things seem quite exorbitant for such an easy installation. A system I could purchase for 5k (4 zones) online will cost me 7k from a local contractor then 5 to 7k for installation--for units that I could ALMOST install myself.
Can you help me understand why contractors would charge so much for what should be a very straightforward installation?
Jim Fisher Jim, I wouldn't attempt to install a multi-zone VRF system yourself. Your contractor would need to attend a 2-3 day training from the manufacturer to be certified to install these then typically has a factory rep commission his first few installs. They look "easy" on the surface but they are actually quite complicated and small errors can lead to problems. Those prices seem pretty standard to me. That HVAC sub isn't getting rich on that install. I wish you the best. Matt
For that price you could get a split system heat pump installed at maybe 500 - 600 sq/ft per ton and have a great system. I work on mini - splits every day. Yes the technology of mini - splits is more advanced than split systems at the equipment level however, there will always be a bulky box mounted on your wall and without a duct system it is impossible to match a properly installed split system AC with regard to comfort.
they put a 3 ton system in my 800sqft house. thats cranked down to 2.5 tons :-(
what is a 2 stage compressor? did you mean condenser?
the compressor is a part inside of a condenser
Outstanding
I have wondered for a long time about the dehumidifier in Texas. I am in Corpus Christi and humidity is even more a problem for us than Austin. have you encountered any science relative to efficiency of the dehumidifier? The whole thing boils down to education for the consumer which you are doing a fine job of.
You forgot what the Chevelle gets you that the Prius doesn’t: laid.
Mitsubishi is such an unpopular brand for hvac in the US. Very common where I came from
Like number 100.
I'm totally not linking this for homework.
(Yes, I cited it using APA)
That is a 1972 Chevelle, not a 1970.
95% efficient gas furnaces waste $5.00 worth of gas per $100. of gas purchased. 80% efficient gas furnaces waste $20. worth of gas per $100. of gas purchased. It gets cold in the South 1.5 - 2 months per year. My natural gas bill has never been over $30. As for humidity, proper heat load calculations will suffice for humidity control. "All air conditioners are dehumidifiers". A single stage heat pump which is sized properly for the load will do the job; a two stage heat pump will control humidity more accurately.