How much energy do you use to heat your home, and what’s the cost?
29 January 2021 | Stephen Marcus
Do you know how much energy you use to heat your home? While many of us try to keep an eye on our energy bills each month, fewer of us know how much goes on heating. But don’t worry – keep reading, to find out how this can be easily fixed!
In a typical household, most energy gets used on heating. In fact, for the average UK household, heating’s responsible for over half of each month’s energy bills1!
So what better reason to get a handle on how much energy you’re using for your central heating? In this guide, we show you how to measure the energy you use to heat your home, how much you’re spending on heating, and how you can make changes to cut your energy use and save money.
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. So you 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! But converting into kWh is pretty simple.
As we explained above, it’s helpful to convert your energy use into kWh. Simply find the unit your energy use is measured in – whether that’s therms or gigajoules – and multiply it by the number beside it:
- 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
A bit of simple calculation is all it takes to find out how much your heating costs:
- 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.
- Use the unit rate 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 possible to work out exactly how much gas heating costs hour by hour – as it can’t 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 you 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. Your unit rate is 14.4p.
- 10,000 multiplied by 0.144 is 1,440 – which means your heating has cost £1,440 across the year.
Average cost of heating a home in the UK
The typical cost of heating a home in the UK is £453.242. To give this some context, the average UK energy bill is £1,042 per year3 – a cost that’s risen in recent years. As we explain in our guide to the average gas and electricity bill, this is despite the fact that energy use has gone down. Instead, it’s affected by changes like rising wholesale energy prices, and higher taxes and levies.
Energy consumption by country: comparing the energy used to heat your home to European standards
First, let’s look at how the energy you use 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 you use 10,000 kWh a year on heating. Simply compare this figure to those in the chart below, to see how you stack up against averages for European countries. Each number shows the average heating used per household each year.
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 – so it’s important to factor in how much energy you use on heating, relative to the size of your home.
There is a way to take varying home size into account. This can be done 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.
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 your usage 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).
It also means you can really start to understand how much energy you use for heating. And that’s a great starting point to help you create strategies to reduce your heating bills, and your carbon footprint.
Top 4 low-carbon heating alternatives
1. Air source heat pumps
Ever thought about using air to keep your home warm? Yep, that’s right – the air outside your home can be harnessed by air source heat pumps for warmth, to heat up your house. They work by absorbing heat from the air outside, using it to heat your home, and give you hot water.
There’s quite a hefty initial investment, but in the long-term, air source heat pumps can save you money, and help you go more green. They’re powered by air, after all – a renewable energy source that can’t be used up! And they can also help cut down your utility bills. Installation costs range from £5,000 to £8,000.
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 your home’s surrounding environment. And just like their relatives, they’re another brilliant way of generating renewable warmth for your 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 sizeable upfront cost here too, with installation costs ranging from £11,000 to £15,000. But just like with air source heat pumps, it’s worth considering the potential rewards you could reap in energy savings, and cutting your carbon footprint.
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’re probably familiar with 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 well worth investing in newer ones. Compared to older models, new storage heaters are much more energy-efficient – so updating yours could be a great way to save energy, while lowering your bills.
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 cheaper rate for energy 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.
How to cut carbon out of your heating, and use it more efficiently
There are 4 key things to bear in mind to make sure your heating’s efficient and cost-effective:
- 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 70°C. And for your hot water, it’s 60°C.
- Thermostat settings – a common mistake to avoid is setting the thermostat higher in the hope that it’ll make your heating warm up faster. We’re sorry to say that this isn’t how it works! 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. To learn more, check out our guide on setting the ideal temperature for your home.
- 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. This is great for stopping heat being wasted where it’s not needed.
- Insulation – One of the best ways to make your heating more energy-efficient is by improving your insulation. If your home isn’t insulated, heat can easily escape – which means you need to use more energy warming it back up! From roof and loft insulation to cavity wall insulation, insulation is a surefire way to cut your heating bills and slim down your carbon footprint. And there are some fun ways to do that – like making a sausage-dog draught excluder.
If you’re looking into loft or wall insulation for your home, you might be able to get up to £5,000 for insulation and double glazing, through the government’s Green Homes Grant. For more on how to finance green home improvements, check out our guide to heating and energy grants.
To learn more about dialling down your energy use, check out our guide to being efficient with heating and hot water.
Frequently asked questions about saving energy in winter
Should I keep the hot water boiler on all the time, or turn it on and off as needed?
It really depends! If you have a gas, oil or liquefied petroleum gas (LPG) system, we’d recommend using a timer or smart thermostat. This means it’ll be on when you need it.
But 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.
Will smart meters save me money?
It’s not possible to say for sure. But they could definitely help! Unlike traditional gas and electricity meters, smart meters measure your usage and automatically send readings to your supplier. They won’t guarantee savings, but they could help you track your energy use, and help you to cut down where energy’s not needed.
By the way, you can get a smart meter free of charge with OVO – giving you the latest technology to help you fight the climate crisis. And we’ve also been crowned winners of the best installation experience around! Book your smart meter installation now.
There’s another great innovation to help you get a better grip on your energy use – smart thermostats! They allow you to control your heating from your phone, and make your home smarter and greener. Read all about the benefits of smart thermostats and how they work, in our practical guide.
Should I set the thermostat on individual radiators, rather than using the main thermostat to control all of them?
Generally speaking, it’s always good to have more control – so we’d recommend using radiator valves to adjust the temperature of individual radiators. This means none of them are heating an empty room, and using energy where they don’t need to.
Problems with your radiators? See our guide on how to bleed a radiator in 7 easy steps.
What’s the difference between controlling the heating using a thermostat, or using radiator valves?
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, we’d definitely advise you to make use of radiator valves. You can set the thermostat to around 20 or 21°, then adjust the radiators in particular rooms, to suit your needs.
Is it more energy-efficient to leave the heating on low all day, or turn it up only when I need it?
Sometimes people think it’s more efficient to leave the heating on low all day – but, in fact, this is wrong! Here’s why:
- 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, of course, it’s much colder outside than it is in – so you’ll 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 more, check out our complete guide to the cheapest, most efficient way to heat your home this winter. Plus learn how to stay warm over winter without using so much heating. And to learn more about how to keep your home well-insulated, head to our ultimate guide to energy-efficient windows and doors.
If my heating is on, should I keep doors open or closed for each room?
Our recommendation is to keep them closed. 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 nice and cosy!
Is a combi boiler cheaper to run?
The answer to this question depends on your lifestyle – which will guide how 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, we recommend making sure that your tank is well-insulated, so it’s as energy-efficient as possible.
Either way, 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.
Want to see if you could save money on your heating bills? Try switching to OVO to see how much you could save. We offer 100% renewable electricity as standard5 – and we’ll plant a tree for every year you’re with us! Get a quote in 2 minutes.
Sources and references:
2 This 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.
5 The renewable electricity we sell is backed by renewable certificates (Renewable Energy Guarantee of Origin certificates (REGOs)). See here for details on REGO certificates and how these work.