Shut that door!…and save money on your energy bill
Headlines
Heat moves from warm rooms to cool rooms, especially in a two-storey home where upstairs is cooler.
Keeping doors closed reduces this significantly in rooms where thermostatic radiator valves are used well. Making sure the heat stays in the rooms you want to keep warm can save you, on average, between £70 and £200 a year in heating costs.
Around half of that saving is by keeping doors shut, according to recent research.
Shutting doors also helps make it harder for cold draughts to enter the house.
This is one of the 'oldest of old' bits of energy advice, but it really does make a difference.
Why does it save so much money?
Most people like to keep their lounge or main living area warm, but want cooler temperatures in bedrooms so that they sleep better. Many also don't feel it necessary to heat all rooms, and save energy in this way.
Leaving doors open actually means the temperatures in different rooms mix with each other. Warmth in the air in one room will slowly be lost to cooler rooms nearby through open doorways. If there are sources of draughts as well, then this happens faster.
This is especially so in houses with two or more storeys, where upstairs is generally cooler. Warm air from downstairs rooms rises gently up the landing, and colder air from the rooms above comes down the stairs at foot level.
Many people feel the cold, particularly on their feet or lower legs. Put simply, if their feet feel cold, THEY feel cold. They then either want to put the heating on higher, or have to put up with feeling cold.
These air movements happen extremely slowly and invisibly, but they do happen. Anyone whose lounge has the stairs leading directly from it will tell you that you can feel cool air coming from upstairs in winter.
When it comes to the rooms you WANT to keep warm, leaving doors open means this:
They won't feel as warm as you would like because of the flow of cooler air at feet level.
The radiators will have to work harder to make up for the loss of heat out of the doorway, which will use more energy and cost you more.
Keeping doors closed as much as possible creates big barriers to these slow air currents.
This also means that cold air trying to come in from outside through draughts in any individual room will find it harder to get into the rest of the house because of the internal barriers the doors create.
Research by Strathclyde University, looking at a wide range of homes, concluded that keeping doors shut, using thermostatic radiator valves correctly and drawing curtains saves between 10% and 30% on heating costs. That's a saving of roughly £80 to £200 a year for the average home (based on tariffs from Oct 1st 23). It estimated that HALF of this saving was from shutting doors alone.
So, by closing doors - even for rooms you are in and out of, all day long - you will save money and keep you and your warmest rooms warmer.
A solution that might help in some homes
Conscious that in some homes remembering to close doors can be difficult to 'enforce' (i.e. teenagers!), these simple, discrete and inexpensive door springs could solve that problem for some people.
The spring tension on them is adjustable, so you can set them up to close the door slowly and gently. Even if they don't close the door completely, they will still be of benefit.
If you have pets, you could put something on the floor so that there is still a gap big enough for them to go in and out, and the heat loss from the room would still be somewhat reduced by the door being partly closed.
These door springs are available widely online, and are usually under £5. A step-by-step video on how to fit one is here, and some written instructions here. They obviously wouldn't be suitable if you have small children around, but they could be an a useful option for many people.
An easier type of door closure to fit (though more visible) is pictured below. Under £15 from Toolstation. These also have adjustable closing tension. Here is a video showing how to fit one.
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Mark Thompson
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