I am proposing to install hydronic radiant heating on my subfloor to take it up a notch as I was also planning to install a ductless heat pump system. On further research, I am discovering that a correctly designed radiant system can make the heat pump system superfluous.
Radiant heat can be a complete heating solution for a home, but to do so successfully there are considerations. Any radiant floor heating system (gas or electric, hydronic or radiant air heating tubes) would need to be sized for the heat load, and so it would need to be designed by an HVAC professional.
To understand the concept of radiant heating and its limitations, I’d start with this page here about home heating and comfortable home design -
To be sure I understand your question, is this a new home build or a renovation project? If you are looking to install a hydronic radiant floor on top of a subfloor that sounds like you have a foundation, is that correct? Radiant floor heat (as you will learn from the article above) only heats single floors at a time, so if you have a basement you’ll need some heat down there.
We have it ingrained in our heads that ‘heat rises’, which is, in a word, wrong. ‘Warm air’ rises, but heat goes in any and all directions. With a forced-air heating system, some heat will find its way to the upper floors, but that’s not really the case with radiant heating, instead it gets cooler the further you are from the source. So, the temperature at knee level will be warmer than at your head level (not by much, but a bit).
So yes, radiant heat can heat an entire home when designed for it. And while a radiant system can provide the necessary heat for a home, it may require make-up heat on an HRV system to meet building code requirements depending on where you are. What is your climate zone or closest city /province / state?
Thank you so much for your input! I also am digesting your excellent article on Designing homes for comfort. I am also examining the feasibility of air to water heat pumps so that I may enjoy radiant heating and cooling. And to answer your questions, the answer is yes to both. It is a new construction on a foundation with insulation between the floor joists. I plan to install the piping above the subfloor and not below. Also, a HRV will be installed as well.
I live in Bellingham, 98229 WA and being in a "frost pocket" we are more a 5B or 5A.
You're welcome Jeremy! We did a combination of radiant floors, air source heat pump and heat pump water heater in our Edelweiss House (not to mention passive heating), and while some may think it to be overkill, we like the idea of a backup heat source.
We use the radiant floor mostly for comfort, to keep it warm enough to walk comfortably on it but we rely on the heat pump as the primary heat source because it is about 3 times more efficient. We can do that because it's a small, open concept house with good circulation and an airtight envelope. The heat pump is a small ductless unit in the living room but pretty much serves the whole house.
So is it redundant? Well....kinda, but kinda not too :) When a house doesn't lose much heat you don't need to add much heat. I wouldn't build a 'Code' quality house where I'd need to drop 15K to meet the demand with a heat pump system along side a radiant floor, but the heat load is so small in that house that what we put in was about 3K installed (Canadian dollars), and it works great.
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Radiant heat can be a complete heating solution for a home, but to do so successfully there are considerations. Any radiant floor heating system (gas or electric, hydronic or radiant air heating tubes) would need to be sized for the heat load, and so it would need to be designed by an HVAC professional.
To understand the concept of radiant heating and its limitations, I’d start with this page here about home heating and comfortable home design -
Designing Homes for Human Comfort
To be sure I understand your question, is this a new home build or a renovation project? If you are looking to install a hydronic radiant floor on top of a subfloor that sounds like you have a foundation, is that correct? Radiant floor heat (as you will learn from the article above) only heats single floors at a time, so if you have a basement you’ll need some heat down there.
We have it ingrained in our heads that ‘heat rises’, which is, in a word, wrong. ‘Warm air’ rises, but heat goes in any and all directions. With a forced-air heating system, some heat will find its way to the upper floors, but that’s not really the case with radiant heating, instead it gets cooler the further you are from the source. So, the temperature at knee level will be warmer than at your head level (not by much, but a bit).
So yes, radiant heat can heat an entire home when designed for it. And while a radiant system can provide the necessary heat for a home, it may require make-up heat on an HRV system to meet building code requirements depending on where you are. What is your climate zone or closest city /province / state?
Hi Mike,
Thank you so much for your input! I also am digesting your excellent article on Designing homes for comfort. I am also examining the feasibility of air to water heat pumps so that I may enjoy radiant heating and cooling. And to answer your questions, the answer is yes to both. It is a new construction on a foundation with insulation between the floor joists. I plan to install the piping above the subfloor and not below. Also, a HRV will be installed as well.
I live in Bellingham, 98229 WA and being in a "frost pocket" we are more a 5B or 5A.
Thanks once again!
You're welcome Jeremy! We did a combination of radiant floors, air source heat pump and heat pump water heater in our Edelweiss House (not to mention passive heating), and while some may think it to be overkill, we like the idea of a backup heat source.
We use the radiant floor mostly for comfort, to keep it warm enough to walk comfortably on it but we rely on the heat pump as the primary heat source because it is about 3 times more efficient. We can do that because it's a small, open concept house with good circulation and an airtight envelope. The heat pump is a small ductless unit in the living room but pretty much serves the whole house.
So is it redundant? Well....kinda, but kinda not too :) When a house doesn't lose much heat you don't need to add much heat. I wouldn't build a 'Code' quality house where I'd need to drop 15K to meet the demand with a heat pump system along side a radiant floor, but the heat load is so small in that house that what we put in was about 3K installed (Canadian dollars), and it works great.