First post, but long time reader. (Tried to edit and fix the wall of text, but no luck.) Thanks to all that make this forum such a wealth of knowledge!! I've built my own home several times over the years and worked construction in my younger years. Previous homes have used fairly standard construction techniques, but we're trying to make this home more efficient. I'm currently working on the budget for a ranch style ICF home with full basement that will be at least partially "walk-out". (ICF used for both basement and main level.) The main level with have roughly 1500 square feet. The basement will be unfinished to begin with, but might be finished off with two bedrooms, bathroom and living space eventually. I will be hiring some labor when needed, especially with the ICF pours, but will be doing a lot of the work myself. The home will be located at about 9000 feet just a little west of Colorado Springs, CO. So we won't be needing any air conditioning. We'd like to go radiant heat... BUT we much prefer hardwood with rugs in the living spaces, and carpet in the bedrooms. We'll probably have tile in the bathrooms and laundry/mudroom. From my reading, it seems that our flooring choices would not be a great option for radiant floors. I've also read some good articles about radiant walls and ceilings so I think that may be a better option which would give lots of floor covering options. Since the home will be ICF, I got to wondering if it would be possible to embed the PEX-AL-PEX into the ICF interior foam, using aluminum transfer plates, and drywall right over that. I could make a template and just use a router to cut the tubing channels into the foam. This would still leave about 2" of foam between the PEX and the concrete. Is that enough insulation to "push" the heat to the inside? I did lots of searching but couldn't find anyone talking about doing this, so I figure I must not be thinking correctly. I'd also consider plutting it in the ceiling, but that would probably take more time/labor since it would have to be ladder work. I haven't yet worked through the Manual J calculations since we're just starting to spec out all the materials. I will do that to determine the needed amount of tubing coverage. Just trying to figure out the best place and manner to install the tubing if we don't put it in the floors. I'd be fine running tubing in the bathroom and laundry floors, but wonder if the water temp would need to be different (lower) there than if we go in the walls. For simplicity and economy, would it be better to run all circuits at the same water temp and put it all in the walls? I'd love to hear from those with knowledge whether I'm crazy or not. Or what they think is the best way to do radiant in a new ICF home with hardwood and carpet floors. Thanks in advance!

With an energy efficient home, you could certainly make hydronic radiant floor heating work with hardwood and carpet. Yes, you will lose some efficiency (especially if you don’t get enough insulation below the PEX) and you will require a higher supply temp (more lost efficiency) required to drive adequate heat through the hardwood and carpet…but this is certainly doable and with an energy efficient home not too terrible. You would first need to accomplish a room-by-room heat loss analysis (e.g., ACCA Manual J or ASHRAE). Then you would design the hydronic radiant floor heating system using this heat loss analysis data to sort out the proper PEX spacing, supply temp(s), circuit flow rates, pump(s) size, etc. You won’t likely experience a warm floor feeling with an energy efficient home, but you won’t have a cold floor either. This is because the floor surface temp doesn’t typically need to get much higher than the thermostat temp setpoint to generate the required heat gain in an energy efficient home.

I would also recommend avoiding below-floor plate system because they are very expensive and perform very poorly, especially when you have hardwood and carpet in addition to the subfloor that you need to drive the heat through. And above-floor plate systems are just as expensive and only perform slightly less poorly. Slabs are the most efficient hydronic radiant floor heating emitters. Next would be products like Warmboard, but which are unfortunately way more expensive.

Whether ceiling/wall hydronic radiant heating will work or make sense for you depends on several variables. For example, will the ceilings/walls provide sufficient surface area to generate the required heat gain and will their proximity to the occupants provide the desired degree of comfort? Ceiling/wall hydronic radiant heating systems are typically more labor intensive projects (read more expensive) and can also limit future use of ceilings/walls (e.g., hanging pictures, lights, etc.) because of risk of damaging PEX.

If I was committed to having hardwood and carpet in my energy efficient home, I would consider using mini splits instead of hydronic radiant heating. Hardwood and carpet don’t feel cold in energy efficient homes even when not heated. Personally, I am not a fan of hardwood floor or carpets for many reasons. I prefer stamped concrete floors that look like hardwood or stone and which can be efficiently heated using hydronic radiant. Just more pet friendly, easy to maintain, don't creak, will support lot of weight, will last forever and are best for people who have allergies.

Thank you Sailawayrb!
I appreciate the information and viewpoint. I guess I need to get my plans finalized and get to the heat loss analysis. Then I can have a better idea of whether the wall plan is feasible. I was thinking about the walls as an option because it SEEMED to require the least amount of additional materials since the "cold side" insulation and drywall would already be there anyway. The only additional material would be the plates. (This is based on not planning to use stamped or polished concrete floors.) If I go floors, I'll have to pour a either a gypcrete or similar base. Or go with an above floor plate system which would also require more materials. For me, labor is less expensive in hard dollar cost than materials.

I do understand the appeal of stamped concrete, but it just doesn't fit our lifestyle or preferences.

I may come back to this thread when I have my heat loss figures. Thanks again for your input!

Sure thing and always happy to offer suggestions!

Yes, it makes good sense to take advantage of things you doing anyhow to reduce the cost of other things you need or desire. For example, if you are pouring concrete slabs, it makes good sense to place PEX in the slabs which then results in the lowest cost and highest performance hydronic radiant floor heating emitter achievable. Or another way of thinking about this, do an integrated design that considers all design aspects and optimizes economics and performance. Sometimes you have to trade things during this design phase to get the overall final build that will optimize your economics and needs/desires.

At your elevation, passive solar cooling/heating should likely be considered too. And if you do passive solar cooling/heating, be sure to include the solar heat gain in the heat loss analysis. And if you do passive solar cooling/heating, you will need to have some amount of interior thermal mass (usually accomplished by masonry floors or masonry walls) to absorb and slowly release the stored solar heat. This thermal mass masonry can also often be heated in other ways (e.g., using hydronics or heated by wood as a masonry heater). And I wouldn’t rule out a combination of hydronic radiant heating and mini splits either as that is often a good approach too. So again, do an integrated design that considers all design aspects and optimizes economics and performance.

Our personal home uses passive solar cooling/heating, hydronic radiant floor heating, and a masonry heater (one 40 pound 60 minute wood firing every other day can heat the entire home for two days). Furthermore, as a result of our ICF constructed energy efficient design, we also don’t require any AC at all in our southern OR climate. Construction photos may be found here if interested:

https://www.borstengineeringconstruction.com/About-Us.html

Take the time necessary to create a fully integrated design for your climate and location which also addresses all of your other needs and desires. All too often, folks are in a rush and start building with just a floor plan and construction drawings, and HVAC is only seriously considered and addressed at the end of the build with far from optimal economics and performance. And don’t forget about fire resistance, especially if you are building on a slope, on top of hill/mountain or in a housing development. Best wishes with your project!

Had a customer about 12 years ago have the same questions. He ended up using a product called Slimline baseboard heat. It's 2 copper pipes bonded to a aluminum plate that's painted white and it becomes your baseboard. Only about an inch thick. There is another company that makes a similar product but I don't know the name, but a search should find it.

Yes, there are many ways to accomplish hydronic radiant heating. Just keep in mind that the ways that use less area for the emitter will require using a higher supply temp (sometimes much higher as in the case of baseboard style) to generate the same living space heat gain. Higher supply temps translate to reduced efficiency. Also, smaller area emitters tend to provide a much lower comfort level as you will feel more temp gradients in the living space. Hydronic radiant floor heating provides the highest comfort level by far. But as in all things, tradeoffs often need to be considered.

I agree totally. Since my business career started as an insulation contractor, I always look to decrease heat loss as the simplest solution to heating and cooling. We just did a project using 2 , 3.5" iso board forms with a 5.5" concrete core. I don't know what the heat loss take off was but I sure it was low.

Sorry for the slow response. I don't seem to be getting notified of replies, even though I'm subscribed. (I'll check my spam settings.)

Thank you all for your perspectives. This is very helpful. Home building always seems to be a collection of compromises and trade-offs, at least when the budget is tight. So I appreciate the great sources of info on this site to help me make wise compromises and not hurt myself in the long run.

Have a great day!