Replies

1. 
   user-2310254 | Apr 05, 2020 11:45am | #1

   Hi PPLP,

   I'll throw out a comment to give you a bump. Like you, I loved the idea of installing in-floor radiant heat. But the more I researched the topic the more convinced I became that it was a big waste of money (at least in my climate). If you are building an energy efficient home with high-quality windows, it is much easier and cheaper to achieve indoor comfort using a mini split. That said, I might consider installing electric floor heat in a master bathroom to avoid having to step on cold tile.

2. 
   pplp | Apr 05, 2020 03:50pm | #2

   Good points that I have been thinking about. What I am considering is using 1 inch pex al pex set on 12 inch centers. So actually not a lot of pipe and actually likely wont need to run the temp very high as I am in zone 4 close to zone 3 Around here the hdd range between 2500 to 4200. Really am looking at low ach . As I mentioned looking to be energy efficient.

1. 
   user-2310254 | Apr 05, 2020 04:36pm | #3

   You might want to read this article (https://www.greenbuildingadvisor.com/article/all-about-radiant-floors).

   In Zone 3/4, AC is usually desirable. With a mini split, you have a system that will heat and cool while delivering great efficiency.

3. Expert Member
   Akos | Apr 05, 2020 09:15pm | #4

   Floor heat is good for taking the edge off troublesome ares. Tile surface, rooms in overhangs or larger windows. You can do this for much less money and very little operating cost with electric resistance floor heat.

   Since you already need the mini split for AC, might as well use it for heat, the hydronic system is a redundant add on that is definitely not cheap. Even if you are DIYing it, your effort is better spent elsewhere, the perceived comfort people think of just not that much in a low loss home.

   P.S. I have done hydronic floor heat a number of ways but I have never heard of using 1" pexALpex. I can't see how that could be serpentined inside joist bays, that stuff is almost as stiff as copper pipe.

1. 
   HFF | Apr 06, 2020 08:37am | #6

   Hello Akos, you have mentioned this method of spot heating with electric wires several times and I am considering it for under a wall with several large windows. Can you tell us how you detail this with hardwood floors? Is it a single wire and can it, for example, be hidden under baseboard trim? Thank you.

1. Expert Member
   Akos | Apr 06, 2020 09:42am | #7

   Standard resistance floor heat mat.

   With hardwood you have to limit the temperature so that you don't warp the wood, but it still can provide plenty of heat. You should size the width of the mat to cover the expected heat load in that area. This would be the loss of the window or the floor if an overhang.

   You can also use standard panel/baseboard heaters, I'm not a fan of the look though. For new install the electric floor heat is not much more cost. There are kits you can install bellow the floors in the basement for a retrofit.

4. Expert Member
   BILL WICHERS | Apr 06, 2020 01:47am | #5

   It sounds like you’re thinking of solar water heaters? Most on here will tell you not to bother, it’s usually a better investment to install more PV. You can use the extra PV capacity to operate electric resistance floor heat. Electric resistance will probably have a lower installed cost than a hydronic system.

   I think you mean you’re planning a “5kw” solar PV system. 5 kWh would be 5 kilowatt hours, which would be a pretty small system equivalent to something less than 1kw worth of panels. It’s important to use the correct units with energy systems, especially when you’re trying to maximize performance the way you want to do in energy efficient homes.

   Bill