How Much More Does Heating Cost for Each Extra Degree?
Turning the thermostat up from 21 to 24 degrees seems like a minor adjustment, but it raises heating consumption by just over 20%. We explain where that figure comes from and five changes that help you spend less without feeling cold.
How much each extra degree costs
According to the IDAE, the public energy-saving agency, each extra degree raises heating consumption by about 7%. With three degrees, the increase is more than 20%.
For example, if heating costs you 100 euros a month, going from 21 to 24 degrees means roughly 20 euros more. These figures are only a guide, because every home is insulated differently.
The IDAE recommends keeping the temperature between 19 and 21 degrees during the day and between 15 and 17 degrees at night. The first four changes below cost little. The fifth costs nothing: you simply have to stop doing it.
1. Air out for just ten minutes
Ten minutes with the windows open is enough to refresh the air in a room. Airing out for longer does not make the air any cleaner.
What it does do is cool the walls, floor and furniture, which then have to be heated again. Turn the heating off while you air out the room. Otherwise, you will be heating the street.
2. Stop drafts getting in
According to the IDAE, air leaks can account for between 5% and 25% of a home's heat loss.
To find them, try a simple test on a windy day. Hold a lit candle near the window or door frame. If the flame leans, air is coming in there. The fix is to fit adhesive weatherstripping at that spot.
3. Use your curtains in two shifts
During the day, open the curtains on windows that get sunlight. That way, your home warms up for free.
At dusk, close them and lower the blinds. This leaves a layer of air between the cold glass and the room, which helps retain heat.
4. Clear and bleed your radiators
If a sofa, a long curtain or drying laundry is covering a radiator, it heats the obstruction first and the room second. Keep it clear.
If a radiator is cold at the top and warm at the bottom, there is air trapped inside. With the heating off, open the bleed valve with a radiator key from a hardware store until water comes out.
Afterwards, check the boiler pressure. If it is below one bar, it needs topping up.
5. Don't turn up the thermostat to heat faster
It is a common habit when you get home to a cold house: turning the thermostat up to 28 degrees so it warms up sooner. It doesn't work.
Most home thermostats work like a switch. They turn the boiler on until the set temperature is reached and then turn it off. The output is the same at 22 degrees as at 28. The only thing that changes is the point at which it stops.
What's more, if nobody turns it back down, the house will keep heating up to 28 degrees, with 7% more consumption for each degree. A thermostat is not an accelerator; it is a limit. And you pay for that limit all winter long.
Frequently asked questions
How much does heating consumption increase for each extra degree?
According to the IDAE, about 7% for each degree. Going from 21 to 24 degrees means just over 20%.
What temperature should you set your heating to?
The IDAE recommends between 19 and 21 degrees during the day and between 15 and 17 degrees at night.
How long should you air out your home in winter?
About ten minutes is enough to refresh the air in a room. It is best to turn the heating off in the meantime.
Does turning the thermostat up to 28 degrees heat the house faster?
No. Most home thermostats run the boiler at the same output whatever temperature is set; the only thing that changes is where it stops.
Informative article written with the help of AI tools from the verified script of the video. The video is in Spanish.