Why do they put radiators under windows?
Andrew Hansen
Published May 28, 2026
This is something most of us learn in school and it helps to explain why radiators are located underneath windows. As the hot air rises from the radiator, the cold air that is coming in through the window pushes against the warm air, circulating it around the room much more efficiently.
Are radiators better under windows?
The best place for a radiator is in the coldest part of the room. This used to be under windows. However, in more modern double-glazed homes, there may not be a cold area, so you can put radiators where they won't affect the use of walls.How far below a window should a radiator be?
Aim for a minimum of 100mm (4") between the top of the radiator and the bottom of the sill. More is fine. Less than that and the radiator begins to look a little cramped. If you need extra heat, consider using a deeper model of radiator (more columns) or adding one elsewhere in the room.Why are baseboard heaters placed under windows?
Placing a baseboard heater right under the window can reduce drafts. The warm air from the heater will rise and heat the cold air flowing down from the window. No more cold draft across the floor. Another good thing happens with the heat source below the window.Why are radiators behind curtains?
The rising hot air from a radiator meets the falling cold air from the window, which would otherwise collect on the floor of the room.How To Install A Radiator Under A Window
How do you dress a window with a radiator underneath?
Floor-length curtains work best with radiators under the windows, but closing them means they'll block the heat generated by the radiator. Generally, pairing up floor-length curtains with other window coverings can do the trick.Does having a radiator cover block heat?
Yes. The good news is that well-designed radiator covers leave plenty of space for the warm air to travel through. A radiator cover could actually even improve your heat efficiency if the cover includes a reflective foil backing, which we mentioned earlier.Is it safe to have curtains over radiators?
Additionally, thick curtains hanging over a rad may actually hinder heat from circulating evenly around your room and could cause you to turn the heat up to compensate. Increased use of energy would increase your heating bills. Decorative hanging drapes should also be kept well clear of radiators.Is it OK for curtains to touch baseboard heaters?
Curtains and any other flammable items should be a minimum of 12 inches away from your baseboard heaters to prevent a fire and to allow for proper airflow that's necessary for the unit to operate.Do radiators cause condensation?
Conventional radiators, fan heaters and convectorsSimilarly, fan-assisted convector heaters and fan heaters heat the air directly and push warm air around the room. We've seen from the science lesson above that circulating warm air will directly cause condensation when it comes into contact with cold surfaces.