Electric heat may effectiveness

[Todd.Brock]

We have a 30 year old 2 story, typical 2x4 construction. There is a bay window / cantilevered bump out in the kitchen. It is very cold in that area. I am going to insulate under the joists, but am considering a heat mat set up. The drywall is open to run a new circuit, and I am tiling the floor later this week.

How effective would a heat mat be at keeping a 6x3 area warm. There are all windows in the bump out so I'm trying to warm that part of the room and not just the floor.

Does anyone have any experience with heat mats?

 

[GCncsuHD]

32 Story?


I have no experience with the heat mays? mats?

But I do have a new construction with two bay windows roughly the same size, one in the kitchen and one in the master bath. Both cantilevered about 4' off the ground, rest of the house is over a crawlspace. Both are well insulated in the walls and joist space, but with plenty of windows. To be honest, I can't tell an appreciable difference in temperature in either other than slightly colder hardwood floor in the one in the kitchen.

I would say insulate the walls, floor, and attic above as well as you can in the area, as well as possibly replace windows with more efficient versions. But I see placing a heat mat under tile in the area as a bit of a waste. Even low-e windows can only hold in so much heat, much of the heat added will escape there. A typical low-e double pane window won't have much of an equivalent R value any higher than R2 or so, but will still be much better than an older less efficient model if your windows are old.

How much time do you spend in that 6x3 area? Enough that you think it will make a difference? I know mine there is one chair at the dinner table that is in the bay window area, other than that it stays unoccupied. Any heat added wouldn't be noticed there.

 

[jkwilson]

Standard building practice is to put registers near windows because it feels cold there. With a bay window, that often isn't possible because there is no access or space under the floor. You may need more insulation underneath, but it may just be the heat loss through the glass that is your problem. If those are original 30-year old windows, they could be losing a lot of heat.

 

[tdkkart]

If you can access the areas above and below the window, make it a point to do so and check the insulation. Many times these areas are missed and allow a lot of cold air to get to the window structure. Often the walls are insulated, but the sloped area below the window is simply covered with pretty stuff with no regard to insulation under the lower window shelf/sill area.

 

[Todd.Brock]

There are 2 registers within 8 ft of each other. I can get to the bottom of the bay window in the basement. There is crusty fiberglass that is laying on the bottom of the joist cavity. I haven't exactly figured out how it's sealed off on the bottom. There are mouse dropping in the old fiberglass. I caught a mouse on a trap this weekend. We just moved in and repairing and insulating is in the works. Windows are 2-3 years out. The entire bay window area is glass. There is one kitchen chair that fills the bump out. I suspect that windows and insulation would fix, but since I had the ability to put down radiant mat, I wanted to inquire That money may be better spent on spray foam it sounds like.

Don't mind the lovely 80's motif. There is a register at the corner of cabinets by edge of bay window and another in bottom right corner. The place is gutted except for the ceiling above the bay