Why are electic heaters in homes installed underneath windows ?

I’ve pondered this from time to time. I realized that if a home is built properly this not an issue. But as a home ages over time the windows/frame at some point will be in need of repair to prevent heat loss for one. With that in mind why are electric base board heaters always installed underneath windows ? Would it not make more sense to have them installed as far away as possible from windows?

The same is generally true of water-filled radiators in most homes here in the UK. I think the reason is that it’s a bit of wall that can’t be used for much else - you can’t put most items of furniture there, so you want to save the full-height walls for bookcases, etc.

It’s not energy efficient, as you say.

I would suspect it also tends to minimize the effects of drafts from those cheap windows. Since you are going to lose heat from the window anyway, you might as well be comfortable doing it.

radiative, conductive and convective heat loss would all be greatest near windows. without a heat source there you would be uncomfortable up to 4 to 6 feet away, your living space shrinks without the heat source there.

The window is usually the coldest spot in the room, and the primary reason to have the heat under the window for mitigating the cold. That’s what makes a room the most comfortable.

This is true even of forced air heating systems – registers are often placed under windows.

The main reasons have already been mentioned:

  1. windows are cold spots, and need extra heat.
  2. furniture is seldom placed in front of windows, so heat sources here won’t be blocked.

Hmmm basically what yall are saying is that I’m not a gecko ? … shit.

Ayup. Forced-air in our house, and off the top of my head I can think of at leats six registers that are located directly beneath windows.

Condensation also forms on windows in the winter. Putting a heater near a window combats that.

I heard that radiators are underneath windows so that the draft from the window will pass over the radiator and carry the heat around the room.

A properly-built window shouldn’t have any draft!

heated air rises.

air cooled by the window surface will sink. even if the window doesn’t leak air (infiltration) you still will get an air current off the window due to cooling. this cool air flow as well as the heat radiating out the window can make the side of you close to and facing the window uncomfortable (if you live where there is serious winter).

I imagine that it would be theoretically more efficient to place the radiators as close to the core of the house as possible. That way you’d get less temperature differential across the windows (and walls), and result in less rapid heat loss. But that would produce a rather unpleasant thermal gradient, where the area next to the radiator would be too hot, the area near the windows far too cold. You’d only have a thin band of comfortable temperature somewhere in the middle.

I just finished a room in my house and the HVAC guys put the 2 vents in right over each window. They put the air return at the opposite end of the room, my impression was that made the air flow across the room.

That’s right. The heated air rises, then flows across the room where it cools, then falls, allowing the warm air to circulate.