Should I leave my heating on?…
As the price of wholesale gas soars; households will be looking at the best ways to save on their energy bills.
But there’s little point scouring the web for a cheaper energy deal right now because there aren’t any!
With thirty energy companies collapsing since last September; using less energy is the best way to save money at the moment.
Hopefully you already have an efficient boiler – if you don’t, it might be time to consider a boiler replacement.
But once you have an energy efficient boiler, what’s the most energy efficient way to use it?
Is it cheaper to leave your heating on low all day or turn it on only when you need it? This is a question we get asked a lot, and it’s a hotly debated one.
We’re always told to switch things off when we’re not using them; so it seems logical that the less time you keep your heating switched on; the less it will cost you.
But another school of thought says that leaving your heating on low all the time is more cost-effective. Because if you allow your house to get cold, it takes more energy to heat it back up again.
So, which is it? In this article we look at the arguments for and against leaving your heating on. And give you advice on which option is likely to be best for your home.
School of thought 1: You should turn your heating off when you’re not using it
How many times have you been told as a child (or maybe an adult!) to switch your appliances off; rather than leaving them on standby, to save energy?
Quite a few, we reckon.
And that’s certainly sage advice. Leaving an electronic device on standby for a prolonged period of time is a waste of energy. It’s much more energy efficient to power it down completely.
So, it seems logical that the same will apply to your heating. If you leave your heating on 24/7, you will end up using more energy.
Supporters of this argument: The Energy Saving Trust
According to experts at the Energy Saving Trust, you should only have the heating on when you need it. They’re clear that by doing this, you’ll save energy and therefore money on your heating bills.
The Energy Saving Trust strongly refutes the second school of thought on the matter. They say that the idea that it’s cheaper to leave your heating on low all of the time is a myth.
According to the EST, if you leave your heating on low all day; you’ll be losing energy all day, because of heat loss. So, it’s better to heat your home only when you need it.
School of thought 2: You should leave your heating on low all the time
Whilst the Energy Saving Trust’s argument sounds sensible, it’s not quite as clear-cut as that.
Some experts argue that it’s actually more energy efficient to leave your heating on at a low temperature constantly to save energy.
At first this sounds absurd – since when did leaving stuff on, actually save energy? But it starts to make sense if you think of it in another way.
Think of it as being like boiling a pan of water on a gas hob.
When you put cold water into the pan; you’ll need a high flame and a lot of gas to get the water to boil.
But once it’s boiling, you can turn the flame down low, and keep the water hot.
If you had turned the gas off completely; and let your water get cold again; you would have to turn the flame up high; and waste a lot more gas, than if you had just let it tick over at a lower temperature.
The same is true of your boiler. It takes much more energy to heat up an entire house from a very cold start; than to just maintain its temperature.
So, by keeping your heating on at a low level, you’ll save energy; because your boiler isn’t working hard to heat your house from a completely cold start once or twice a day.
Weather compensation and leaving your heating on
If you have weather compensating heating controls; you’re probably already familiar with the idea of maintaining a constant temperature rather than turning your heating on and off.
Weather compensators are one of the four additional energy saving devices recognised by the Boiler Plus regulations. They monitor both the temperature inside your home, and the temperature outside, and adjust your boiler’s operation accordingly.
A weather compensator tells your boiler to increase or decrease the temperature of your radiators; to match the heat loss caused by the weather.
This is because heat is lost more quickly on a cold day, than on a warm one.
So, instead of your boiler switching on or off depending on when your home gets too cold or too hot; weather compensation monitors and maintains your chosen temperature without having spikes of over and underheating.
This provides a more comfortable and consistent environment. And with the boiler flow temperature being kept as low as possible, around 55°C or less; the boiler can condense as it is designed to; running more efficiently, and saving you money.
Viessmann conducted research at Salford University and found that a simple weather compensation sensor typically saves the householder anything from 10-30% off their energy bills. Or a good £40-£100 or more per year.
A report by an environmental science consulting group; published similar estimated energy savings of 10-40% for electronic weather compensators in one-family houses.
So, despite it sounding a little counterintuitive, leaving your heating on low can save energy in some circumstances.
There is a ‘but’ coming…
Heat loss and leaving your heating on
Whilst leaving your heating on can work well if you’ve got decent insulation; it won’t if your home has high levels of heat loss.
To learn more about heat loss and why it’s important, you can read our related blog here. But in a nutshell, all buildings lose heat. The more they lose, the more energy it takes to heat them.
Buildings will have high levels of heat loss if they have poor to no insulation, single glazing, and poor airtightness.
So, if your home suffers from high levels of heat loss; you’ll need to use more energy to maintain the inside temperature – even at a low temperature.
This means that leaving your heating on all the time would be more expensive – it certainly wouldn’t save you money.
This leads us on to the advice from TheGreenAge. TheGreenage is the UK’s premier energy saving advice portal, covering heating, insulation and renewable technologies…
TheGreenage: it’s down to insulation
The Greenage say that whether you should leave your heating on all the time or not; depends entirely on how well insulated your home is.
They say that if your home is very well insulated; you’re better off leaving the heating on at a set temperature, because there is little heat loss occurring.
But, if your home is a Victorian property with high levels of heat loss; then you’re better off following The EST advice and just heating it up for the times when you need it.
This would probably be first thing in the morning, and in the evening before you go to bed.
This is because any heat you generate will be lost fairly quickly through the fabric of your building; so your boiler would have to work incredibly hard to maintain the temperature all day.
If you work during the day, it should make things a lot cheaper compared to leaving the boiler on.
Perhaps the reason that The EST has run with the blanket advice to switch our heating off; is because most homes in the UK suffer from high levels of heat loss.
A report by the Climate Change Committee (CCC) says that our housing stock is: “one of the oldest and worst insulated in Europe, with 38% of homes built before 1946 and only 15% since the 1990s.”
Can I test which method will work for me?
If you want to put the two theories to the test, you can.
If you think you have an energy efficient home; you can compare your energy usage when you leave your heating on; compared to programming your heating to come on at certain times of the day.
Over the course of two weeks, test each method and take gas readings. But do bear in mind that if there is a change in the weather, it won’t be a fair comparison!
And the winner is…
As is so often the case in life, the answer to whether or not you should leave your heating on or not; is – it depends!
There isn’t a one-size-fits-all approach when it comes to heating. What’s right for your home will depend on many factors, such as:
- the age and type of property you live in;
- the amount of insulation you have;
- whether you have double or single glazing;
- your heating preferences – i.e. how warm or cool you like your home to be;
- how often you’re at home during the day;
- What heating controls you have;
- how you use your heating;
- the age of your boiler;
- how many people live with you.
But if the two arguments in today’s debate make anything clear it’s this: heat loss is incredibly important when it comes to heating our homes.
If you want to improve your energy efficiency, save money, and reduce your carbon footprint, insulation is vital.
And the good news is, insulating your home can be something that’s fairly cheap and straightforward to improve.
By simply putting down some draught excluders or using heavy curtains you can start to reduce your home’s heat loss. And keep that heat for as long as possible – regardless of whether you leave your heating on, or turn it off.
Useful links
The Greenage: Is it cheaper to leave your heating on all the time?
The Energy Saving Trust: Take control of your heating at home
The Cliamte Change Committee Publication: UK housing – fit for the future?