guide

How much energy do you use to heat your home, and what’s the cost?

20 October 2021 | Stephen Marcus

Most energy gets used on heating in a typical household. In fact, for the average UK household, heating is responsible for over half of each month’s energy bills1.

In this guide, we cover how to measure the energy used to heat your home, how much heating is costing, and how to make changes that can help cut energy use.

Measuring the energy used to heat your home: how many kWh you need to heat a house

So how much does a typical home use? And how do we measure it? We use kilowatt hours (kWh) as a standard measurement– with 1 kWh measuring the energy used to keep a 1,000 watt appliance running for an hour.

Whether you use natural gas, fuel oil, electricity, or something else, it’s best to measure the energy used to heat your home in kWhs.

For more help getting your head around kWhs, and how they work, check out our guide to understanding kW and kWh.

How to calculate the energy you use for heating

Most households will use the same fuel for heating as for other things. For example, you’ll likely use gas for both heating and hot water. That means we need a way of working out what percentage is used for central heating, and how much is used for other things, like hot water. Here’s an example:

  • Let’s say a home only uses electricity, and over a year it uses 16,000 kWh for everything – including lighting, appliances, cooking, hot water and heating
  • If we know that over the 6 months when the home isn’t heated, it uses 3,000 kWh, we can assume that roughly the same amount is used over the winter months for everything except central heating
  • So over a year, 6,000 kWh is used on everything but heating, and the remaining 10,000 kWhs are used on heating alone

How to convert your energy use into kWh

Depending where you live, and the type of fuel you use, you might be calculating your energy use in one of many different units. Just like with measuring water in litres or pints, there are lots of different ways to measure energy.

As we explained above, it’s helpful to convert your energy use into kWh. Find the unit your energy use is measured in – whether that’s therms or gigajoules – and multiply it by these numbers:

  • For therms – multiply by 29.3
  • For tons of oil equivalent – multiply by 11,630
  • For gigajoule – multiply by 278
  • For kilocalorie – multiply by 0.00116

So now you should be able to learn how much of your energy bill goes on central heating! And now that you’ve converted it to kWh, you can see how your energy use compares. 

Bear in mind that certain other factors can affect the amount of energy needed to heat your home. The size of your home, the local climate, the temperature of your thermostat, the heating system, and how your home is built all play a role.

How much does it cost to heat a house? Central heating costs per hour

how much does it cost to heat a house

It can be a little tricky, but here’s how to work out how much your heating is costing:

  • First, work out how many kWhs of energy you use on heating per year. Follow the steps above to see how to do this.
  • Your energy tariff is made up of 2 rates. The first is the standing charge, which is charged each day, no matter how much (or little) energy you use. The second is the unit rate – which is how much you’re charged for the energy you actually use.
  • It's only the unit rate that's needed to work out how much your heating is costing each year. (It’s calculated in kWh). 

Gas central heating cost per hour and per year in the UK

Unfortunately, it’s not currently possible to work out exactly how much gas heating costs hour by hour – as it can’t easily be separated out from your total household gas use.

But as we’ve described above, you can isolate the energy you use for heating – which means you can still work out how much it costs each year:

  • Let’s say you have a gas boiler, and use 10,000 kWh of energy on heating per year. Your unit rate is 3.8p. 
  • 10,000 multiplied by 0.038 is 380 – so £380 is how much your heating has cost you across the year.

Electric central heating cost per hour and per year in the UK

Likewise, if you have an electric boiler, it’s not possible to separate the cost of your heating hour by hour from the other things you use electricity for.

But you can still work out how much energy you use for heating across the year, so you can see how much it costs:

  • Let’s say you have an electric boiler, and use 10,000 kWh of energy on heating per year and your unit rate is 19p. 
  • 10,000 multiplied by 0.19 is 1,900 – which means heating cost £1,900 across the year.

Average cost of heating a home in the UK

The typical cost of heating a home in the UK in 2018 was £453.242. To give this some context, the average UK energy bill in the same year was around £1,184 per year3 – although this cost has risen significantly in recent years.

Energy consumption by country: comparing the energy used to heat your home to European standards

First, let’s look at how the energy used in your home compares to the rest of the UK. Then we’ll compare that to some of our European neighbours. Let’s say you’ve calculated that your home uses 10,000 kWh a year on heating. Compare this figure to those in the chart below, to see how this looks against averages for European countries. Each number shows the average heating used per household each year.

heating-costs-by-country

As you might expect, a country’s climate plays a key role. For countries with cold winters – like Denmark – 10,000 kWh is quite a low figure. But in a warmer country like Spain, it’s on the higher end of the scale. 

Heating energy (kWh) per square metre: how much gas and electricity do you use per floor area?

Another thing to consider is the size of your home. This is something the figures above don’t account for – and it’s helpful to factor in how much energy you use on heating, in relation to the size of your home.

This can be taken into account by measuring energy use in relation to floorspace. Here’s an example of how this works:

Let’s say your home uses 10,000 kWh of energy per year on heating, and it has a floor area of 100m2

  • To work out your energy use per floor area, you simply divide the energy use by the floor area – in this case, that means dividing 10,000 by 100
  • This gives you a figure of 100kWh/(m2a) – with the “a” meaning “per annum” (or each year)

The chart below shows how those same European countries shape up when it comes to average heating use, relative to floorspace.

heating costs per square meter

As you can see, this gives us a quite different picture. When it comes to heating per square metre, we’re not far above Greece or Italy – which is interesting to note, given the warmer weather they enjoy through much of the year.

Estimating how much energy you use to heat your home per unit of floor area is really useful, because it lets you compare the usage in your home to other benchmarks. The most famous of these is perhaps the Passive House (Passivhaus) standard, which limits energy used for heating to just 15 kWh/(m2a).

4 low-carbon heating alternatives

1. Air source heat pumps 

Did you know air can be used to keep homes warm? Heat pumps absorb heat from the air outside, and use it for heating and hot water. They even work in winter. 

Air-source heat pumps are a greener alternative to regular central heating. They make use of air – a limitless natural source that can’t be used up. And they can be run on 100% renewable electricity. The total cost of buying and installing a heat pump ranges from £7,000 to £13,000.

Read our guide to find out everything you need to know about air source heat pumps and how they work

2. Ground source heat pumps

Ground source heat pumps, like their air source relatives, are an alternative to a traditional boiler, drawing heat from the surrounding environment. And just like their relatives, they’re another brilliant way of generating renewable warmth for home.

They work through a network of pipes buried underground, near the house, where a mixture of water and antifreeze is circulated around a loop of pipe. Heat from the ground is absorbed into the fluid, which is then passed into a heat exchanger in the pump.

There’s a very high upfront cost here too, with the cost of buying and installing ranging from £11,000 to £18,000.

Want to know more? Our quick and easy guide gives you all the details on ground source heat pumps

3. Solar thermal panels 

While you might have heard of solar panels, you may not have heard of solar thermal panels. They’re a type of solar panel especially intended for turning sunlight into heat.

But rather than converting the heat from the sun into electricity, they use it to directly heat water. And in fact, they’re more energy-efficient than traditional solar panels. This is because heat waves carry more energy than sunlight, and there’s no transformation process needed to turn that energy into electricity.

Check out our in-depth guide to learn more about the best low-carbon heating options

4. Storage heaters

If you use storage heaters in your home, it could be worth investing in newer ones if you're able to. Compared to older models, new storage heaters are much more energy-efficient – updating them could be a good way to save energy, while lowering energy costs. 

Powered by electricity, they charge overnight, using off-peak (i.e. cheaper) energy, which can then be used during the following day. This is especially important to note if you’re on a time-of-use electricity tariff, such as Economy 7, which means you pay a lower rate for energy used overnight (usually 12pm-7am). 

Interested to find out more about storage heaters? We've put together a practical guide to explain how storage heaters work, and their costs and benefits.

Saving energy and using it more efficiently for heating

There are 4 key things to bear in mind, to help make your heating more efficient:

  • Boiler settings – the temperature you set your boiler to is the temperature at which it heats water – and you’ll want the temperature to be no higher than you need. For your heating, the ideal temperature setting is around 70C. And for your hot water, it’s 60C. 
  • Thermostat settings – a common mistake is setting the thermostat higher in the hope that it’ll make the heating warm up faster. Instead, set it to the temperature you want. The thermostat measures the temperature of the room, and once that temperature has been reached, the boiler stops sending hot water to the radiators.
  • Thermostatic radiator valves – these allow you to adjust the temperature of individual radiators, which means you can set the best temperature to suit different rooms. 
  • Insulation – If you’re able to, one of the best ways to make your heating more energy-efficient is by improving your home’s insulation. If your home isn’t insulated, heat can escape – which means more energy is needed to warm it back up. From roof and loft insulation to cavity wall insulation, there are lots of different options for insulating your home. 

Looking into loft or wall insulation for your home? You might be able to get help to pay for these improvements, as part of government initiatives. Check out our guide to heating and energy grants.

If you’re worried about heating costs or you’re struggling financially, please get in touch with us – we’re here to support you.

Frequently asked questions about saving energy in winter

This depends on what type of heating system you have. If you have a gas, oil or liquefied petroleum gas (LPG) system, we’d recommend using a timer so it’s only on when you need it. 

If you use an electrical immersion heater, it could be worth heating your water during the night. Especially if you have a time-of-use tariff such as Economy 7, where energy is cheaper at night.

Read our guide to Economy 7 tariffs and meters, and how it all works.

Smart meters can help you save energy, as they show your energy use in real time – which makes it easier to spot ways to save on costs too. They won’t guarantee savings but we do think they’re really helpful. 

If you’d like one, you can get a smart meter installed free with OVO – book a smart meter installation here.

Using radiator valves to adjust the temperature of individual radiators means you can turn off radiators completely when rooms are empty, and you have more control over the temperature of rooms that are naturally warmer or colder. Basically, radiator valves will help stop energy being used where it’s not needed.\ \ Problems with your radiators? See our guide on how to bleed a radiator in 7 easy steps.

When you’re trying to decide whether it’s better to use radiator valves or your thermostat to control the heating, here are some key points to consider:

  • Does your house have multiple thermostats? If the answer’s yes, you’re less likely to need radiator valves. This is because each thermostat should allow you to adjust the temperature in different parts of your home.
  • But if you just have one thermostat for your entire home, radiator valves might be a good choice. You can set the thermostat to your ideal temperature°, then adjust the radiators in particular rooms, to suit your needs.

It’s better to only turn it on when you need it – this is because:

  • Heat is always being lost when the heating is on – even in really well-insulated homes.
  • The colder it is outside, the more heat you’ll lose. In winter, it’s much colder outside than it is inside – this means your home will lose a lot of heat whenever you have the heating on.
  • The longer you have the heating on, the more heat you’ll lose. That’s because your heating will be powering up at regular intervals, to keep catching up with the warmth that’s escaped.

To find out about how to insulate doors and windows, head to our ultimate guide.

It’s best to keep them closed, trapping the heat in each room. Most heating systems work by creating a "convection current" in a room. This describes the way that hot air rises, moves round the room, sinks down, and travels back to the heater, to be warmed up once more.

By keeping the door closed, you can ensure this cycle isn’t disturbed, so the room stays as warm as possible.

The answer to this question depends on much hot water you use, and when you need it4. Standard boilers heat water, and keep it in a tank until it’s needed – while combi boilers heat up water instantly.

  • For small households that don’t use a lot of water – a combi boiler is likely the best choice, as it means hot water won’t be left to go cold, as is often the case with a standard boiler.
  • For large households that use a lot of water – a regular boiler could be the better option, as combi boilers tend to be less efficient at heating water. Here, it’s helpful to make sure your tank is well-insulated, so it’s as energy-efficient as possible.

When it comes to replacing your boiler, having the most efficient boiler possible makes a huge difference. Aim for an A-rated condensing boiler, if possible.

**For more information on boilers, head to our quick guide on different types of boilers, and how to choose the right one for you.**


Sources and references: 

1https://energysavingtrust.org.uk/advice/heating-and-hot-water/

2This is calculated on the basis of a home with a gas boiler. This uses the average annual space heating energy consumption of a UK household of 10301.31kWh, according to 2018 data from Odyssee here and converted into kWh. This is multiplied by the UK’s average unit gas price of 4.44 pence/kWh, as per Ofgem reporting here.

3https://www.ofgem.gov.uk/publications-and-updates/infographic-bills-prices-and-profits

4https://energysavingtrust.org.uk/advice/boilers/

5100% of the renewable electricity we sell is backed by renewable certificates (Renewable Energy Guarantee of Origin certificates (REGOs)). See here for details on Renewable Energy Guarantee of Origin certificates and how these work. A proportion of the electricity we sell is also purchased directly from renewable generators in the UK.