Why are radiators under windows?

In this article, we identify why radiators are so often situated underneath windows, as well as some other places your radiators could be positioned.

Why are radiators put under windows?

Traditionally, when central heating was a brand new concept, the part of the room that was coldest was around the window. The Victorians didn’t have double or triple-glazed windows, so their single glazing would let lots of cold air in, cooling the room down and creating a draught. Therefore, when central heating was becoming more popular in upper class houses, it made sense for the radiators to be placed in the coldest part of the room, beneath the window.

Due to the laws of thermodynamics, cold air falls and warm air rises. 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. If you were to place a radiator in the middle of the room instead, the heat wouldn’t fill the room. Instead, you’d find cold spots. This theory doesn’t apply as much in the 21st century, as our windows aren’t as draughty.

It’s thought that many radiators were positioned here for another practical reason too. The space under the window is rarely used for furniture - people want to be able to stand in front of the window and look out of it. Therefore, this space on the wall underneath the window seemed like a very practical place for a radiator. Not only is it tucked out of the way, but it becomes less noticeable under a window than it would in the middle of a wall.

Nowadays, our windows are much more efficient. Many homes will have double-glazing or even triple-glazing, and there are smaller gaps around doors and windows. Our homes are much more sealed than in the 19th century too, when you could feel the cold air blowing through gaps in the floorboards. This means that we now have much more choice when it comes to positioning our radiators where we want. 

Where to position radiators in a room

If you still have single-glazed windows at home, we’d recommend keeping your radiators positioned underneath them for maximum warmth and efficiency. However, if your windows are double-glazed, there are alternative locations for your radiator.

When you’re choosing a new location, we’d suggest thinking about the furniture that you have, or will have, in the space. A radiator should never be blocked off by furniture, as it becomes much less efficient and you may find the room doesn’t heat up very much. So, for example, putting a sofa in front of your radiator is not going to be very beneficial at all. Try to find a wall that is bare and has little furniture against it. You should also be careful of what’s on the wall above the radiator. Plastic shelves or pieces of artwork could melt if they’re placed too close to the appliance.

You may also want to think about where the coldest parts of your room are. If it isn’t the window, do you have a draughty door or an air vent that lets in cold air? If this is the case, you may want to put your radiator here to keep the room as warm as possible. Depending on the size of your room, you may need two radiators so try to find a second position that’s also practical.

Finally, you don’t have to limit yourself to a horizontal radiator. If you don’t have a huge amount of wall space, you could install a vertical radiator like the one below.

Not only is this radiator practical, but it looks really stylish and almost becomes a piece of art or a focal point. This design shows that you don’t have to hide your radiators away. However, before you purchase one, you should make sure that your heating system will be able to cope with a horizontal radiator.