Radiant heat solution for temperate climate

crystaln

I live in a pretty sunny area of Northern California, where I rarely need that much heat. However I am inclined to make the heat I do use with radiant for both comfort, and because I have 3 gas HVAC systems I'd rather not have to fire up depending on where needs to be heated.

I am in the process of replacing very old carpets with likely (engineered?) hardwood in some areas, and something more durable in others, so this is a good time to address this.

Because I'm in a temperate climate where I don't need that much heat very frequently, I'm not very worried about the efficiency of the system. I'm most worried about cost of installation, and other impacts the system might have like the thickness of the floor. I also want to add sound insulation.

Most of the system will be on existing plywood subfloors.

Hydronic systems are thick, which is going to make other things in the house complicated, like transitions to older floors, doors, etc. It might be manageable.

Electronic systems seem like they will require new expensive 240v electrical lines for each zone more than 100sq ft, although given their thin-ness and simplicity I'm inclined toward them, maybe even installing them and wiring them up later when I want to spend that money on electrical.

However maybe I can get by using existing electrical and running at lower amperage given that I have pretty moderate heating needs (rarely gets below 40 outside). That also makes sense for anywhere with hardwood on top.

Based on these requirements can anyone direct me toward a good economical solution?

EdTheHeaterMan

What is below the floor? What ever you use to heat the room, it will also heat the area below the floor too. YES. HEAT GOES DOWN TOO! Think of the sun in the sky. If that heat only went up, this planet would be q pretty cold place!

So your radiant heat will go down the same way the sun's heat goes down. To put that energy into your room and not into the space below the floor, toy will need to add significant insulation below the floor to make that system work properly. There is a story about this that got fixed because of a divorce here:

So if you can access the space below the floor to install the installation, then you can staple up PEX tubing to the bottom of that floor before the insulation is placed in there.

If you can only access that floor space by removing the floor boards to install the insulation, then the job is not going to be the low cost you are looking for.

hot_rod

How any square feet are you thinking about heating? There are some ball park figures per sq ft. out there before you spend a lot of time on designs if it is out of budget.

crystaln

It varies what's below, in some cases another space, in others foundation is like 6" below (house is layered down a hill). Installing from underwent seems very challenging.

The first space is around 300 sqft., though I could probably only heat 200 sqft of it.

One future floor is more like 1000 sq ft.

> Think of the sun in the sky. If that heat only went up, this planet would be q pretty cold place!

Not to be pedantic, however the sun provides radiant heat, which is very different from the "radiant" heat of the floor, which is actually conductive heat. These are very different forms of heat transfer, solar radiant heat being in the form of electromagnetic waves (light) and therefor impervious to the effects of gravity. Once the solar radiant heat warms the atmosphere, the heat does rise.

"Radiant" heat (actually conductive heat - it's very unfortunately named) on my ceiling is not going to do much. It will heat the air around it, which will stay almost entirely on the ceiling and above head level.

hot_rod

Actually radiant surfaces do heat the objects they see, in addition to conductive transfer the objects that touch the surface. Like the sun but nearly as powerful radiant floor heat transfer
Radiant ceilings will warm the floor, but not under the couch
Heat energy travels to colder surfaces, the speed is dependent on the delta T

Hot air, being more buoyant, rises.