Why Are Radiators Under Windows?
Why Are Radiators Under Windows?
Have you ever wondered why radiators are under windows? Well, the answer is quite simple.
Radiators sit under windows because the heat that rises from them is able to create a thermal curtain that blocks cold draughts from entering the room. This guide will cover why radiators are placed under windows and whether under-window radiator installation is the right choice today.
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Key takeaways
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Origin: The convention of radiators being placed under windows began as a way of shielding cold draughts entering through single-glazed windows.
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How it works: The way this works is that the rising heat from the radiator would create a thermal curtain of sorts that could block the cool air sinking from the window.
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Relevance today: This placement is now far less relevant than it once was, owing to modern double and triple glazing, though some homes still use it for furniture-layout reasons.
Why are radiators traditionally placed under windows?
The reason why radiators often sit under windows is a dated one and originates from back when single glazing made windows the coldest surface in a room.
The idea was that the cold glass chilled the air beside it, and that cold air sinks and spreads across the floor. Placing a radiator underneath the window, then, offered a chance to intercept the sinking cold air with rising warm air to form a kind of thermal curtain.
Do radiators still need to be under windows?
Modern double and triple glazing has made the need for under-window radiators far less today than it once was. This is because newer window insulation loses far less heat than old single glazing did, so there is less cold air entering a room to shield against and, so less need for a thermal curtain.
There are still benefits to under-window radiators, though:
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The heat can serve to reduce condensation on windows.
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This, in turn, can prevent the moisture buildup that leads to mould.
Where is the best place to put a radiator?
There are certain rooms that still benefit from under-window radiators, though in many cases the radiator can be placed elsewhere. These are the scenarios that benefit most from having a radiator under the window:
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North-facing rooms.
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Rooms with bay windows.
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Rooms with floor-to-ceiling glazing.
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Bathrooms for condensation control.
Having radiators under windows can also cap their height, as windowsills are often 900–1000mm high, meaning radiators must be capped at a height of 700–800mm, making them shorter than if they were placed somewhere else. The smaller the radiator, the less BTU or heat output.
Also, when a radiator is under the window, the curtains can sometimes block the thermostatic radiator valves. This gives the radiator an inaccurate temperature reading and prompts it to shut off. If you do have a radiator under the window, try to keep curtains clear of the radiator face rather than tucking them behind it.
So, should radiators be under windows? It depends. There are certainly some benefits to them being there in some situations, but for the most part, as window glazing has improved, their placement under windows has become outdated. Interior walls are a valid modern alternative, though some still choose the under-window placement for furniture-layout purposes.
Why Are Radiators Under Windows? - FAQs
The need for radiators under windows, whilst not as relevant as it once was, can still bear some benefits for certain rooms. Ultimately though, radiators can be placed anywhere in a home.