eli5: Why are radiators in houses often situated under a window- surely this is the worst place and the easiest way to lose all the heat?
In: 2851
There’s a great story behind it. The practice of putting steam radiators under windows dates back to the 1918 Spanish flu pandemic. It was believed that the flu was caused by bad air, so radiators were put under the windows to allow the occupants to leave the windows wide open to let in fresh air no matter how cold it was outside. The radiators would heat the incoming cold air.
There are lots of answers already, but I personally hate radiators and think it’s eapecially stupid to put them under a window (where I want to put a plant) and then put curtains around them so you are warming the one place on the wall with the worst insulation and putting a barrier around the whole situation.
Perfect old timey solution for when gas was almost free, the world wasn’t dying from global warming and money needed to go towards the fossil fuel industry.
These days: forget about radiators, get airco/heatpump and low temperature heating such as floor heating, and insulate (double glass at the very least)
[deleted]
If you have a room with a window on one side where heat is escaping, and a radiator on the other, you’ll have a gradual drop in temperature across the entire room between the radiator and the window, and the side by the window will be quite cold
If the radiator is under a window, it will be warm there because it’s near the radiator, and the rest of the room will also be warm, because there is no where in the other part of the room for the heat to escape
If you have a room with a window on one side where heat is escaping, and a radiator on the other, you’ll have a gradual drop in temperature across the entire room between the radiator and the window, and the side by the window will be quite cold
If the radiator is under a window, it will be warm there because it’s near the radiator, and the rest of the room will also be warm, because there is no where in the other part of the room for the heat to escape
Radiators don’t just work by heating the air immediately around them, they also start air currents driven by warmed air rising to the top of the room and cold air coming in from behind to replace it. The bigger the _temperature difference_ between cold and warm air, the faster those currents will move, and the less time it will take for all the cold air to pass over the radiator and get heated. So the most efficient place to put a radiator is the coldest spot in the room, which is traditionally under the window.
Many have pointed out that putting the under the window makes sense thermodynamically. Architecturally: radiators are often installed in niches. It doesn’t make sense to weaken the wall in more places than necessary. Since the window is a weak point of a wall anyway, you can get away with having thinner walls bellow it. Also, the windowsill will cover the radiator and you thus lose less wall space for shelfs and such.
Nobody has mentioned that having curtains closed (even if only thin ones) helps prevent the cold from flowing inwards into the room. They help direct the cold air downwards to the radiator, which is warm, that in turn produces a warm air current between the glass and curtain heating the cool air.
VERY simply:
It creates a “heat wall” of air that blocks the cold from coming in through the window, trapping the warm air inside.
To add, your going to have heat escape regardless of where it’s situated, cold and warm air are going to want meet homeostasis. Having heat sources at locations where there is heat loss or rather cold gain helps equalize the temperature in the area instead of hot and cold spot.
Latest Answers