guide

The cheapest, most efficient way to heat your home this winter

21 December 2020 | Stephen Marcus

There’s a bewildering amount of advice out there on how to heat your home more cheaply and efficiently. Should you actually keep the heating on low all day, rather than switching it on and off as needed? Are there really benefits to painting your radiators black? And is it worth investing in improving your insulation? All is about to be revealed...

This guide is intended to provide general guidance only. It is not intended to give you advice on your personal financial circumstances. You should seek independent professional advice if you’re unsure about anything mentioned in this guide or what choices to make.

For most households, heating is one of the biggest energy drains. In actual fact, it makes up over half of the UK’s household energy bills1. So it stands to reason that you could make big savings on your bills if you can reduce the heating you’re using through winter.

With so much information out there, we’ve put together an easy-to-digest guide giving the best money-saving tips for lowering your heating costs. From the different ways you can use central heating, to the alternative systems for heating your home, we’ll walk you through what’s out there, and give you the information to decide what’s best.

What are the key tips for efficiently using central heating? 

Most of us use central heating to keep our homes warm in the colder months. On a chilly day, there’s nothing better than hearing the click of the thermostat, and the sound of hot water running through the pipes. Lovely!

There’s just one problem: it’s not a very efficient way to heat a home. At every stage of the process, energy is lost in heat transfer – whether from the hot water to the radiator, or from the radiator into the air.

Here are the 3 things you need to consider for running your heating efficiently and cost-effectively:

Boiler settings 

Most traditional central heating systems are controlled by your boiler. The temperature you set your boiler to is the temperature at which it heats water. So the key here is to set the temperature 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 

There’s a common misconception that turning the thermostat higher will make the heating warm up faster – but sadly, this isn’t the case! What the thermostat does is measure the temperature of the room, and once the chosen temperature has been reached, it tells the boiler to stop sending hot water to the radiators.

Read more about the average room temperature and how to set your thermostat to the ideal level.

Thermostatic radiator valves

A better way to gain extra control over your heating is via thermostatic radiator valves (TRVs). These allow you to adjust the temperature of individual radiators, so that they’re the right temperature for the room you’re in. By setting the right temperature in different rooms, you can more easily ensure that there’s no heat being wasted where it’s not needed.

Are you looking to cut your heating bills this winter, with an energy supplier that’s committed to going green? At OVO we provide affordable and competitive energy prices, with 100% renewable electricity as standard2, and we also plant a tree for every year that you’re with us. Get a quote now.

Try OVO Greenlight

Is it more energy efficient if I leave the heating on low all day, or turn it up only when I need it?

It seems logical that the less time you keep your heating switched on, the less it will cost you. But another school of thought suggests that the energy used to power your heating up from a cold start costs more than leaving it at a level temperature all the time.

So which is the best way to use central heating? 

We believe the most efficient way to heat a house is to programme your heating system so it’s only on when you need it.

That means setting your heating timer and thermostat so your home is warm only when you want it to be. You could also buy separate room thermostats, to make sure your bedroom’s toasty when it’s time to get up in the morning, and your living room’s cosy when you’re watching TV in the evening.

That really is the cheapest way to heat a house, and keep your home at the temperature you want.

How long does it take to heat up a house from when it’s cold? 

It’s true that it does require a certain amount of energy to kick-start your heating system and warm your house up when it’s cold. But it also takes a lot of energy to keep the heating at a level temperature 24 hours a day.

The idea that leaving your heating on all the time is more efficient is flawed. That’s because it doesn’t account for the fact that heat is always being lost when the heating is on – even in the best insulated houses. Remember these key points:

  • The colder it is outside, the more heat will be lost. During the winter months, when it’s much colder outside than it is inside, you’ll be losing a lot of heat whenever you have the heating on.
  • This means that the longer you have the heating on, the more heat will be lost. That’s because your heating will need to power up at regular intervals, to make up for the warmth that’s escaped

Plus, if your house is poorly insulated – or not insulated at all – the heat loss will be even greater, and your heating could be using constant energy to maintain an even temperature. This would work out much more expensive than just turning it on and off when you need it. So it definitely isn’t the most efficient way to heat a house. 

If your home isn’t properly insulated, you can also lose heat in the following proportions:

  • 33% through the walls
  • 26% through the roof
  • 18% through the windows
  • 11% through the door and the floor

Want some more energy-saving tips? Read our guide on how to make your home more energy-efficient.

My house is really well insulated, with triple glazing, loft and wall insulation, and draught excluders on every possible gap. Will it still lose heat?

We’re sorry to say, yes, it will. Even if you never open your windows, you’ll still have to open the door occasionally! You’ll also need to drain the water from your basins and bath. All these actions can lead to a certain amount of heat loss.

It’s still worth insulating your home as well as you can. Whether you decide to leave your heating on all the time, or turn it on and off, the better your home is insulated, the less energy you’ll need to use – and the lower your energy bills will be. 

If you’re into crafts, why not try making your own sausage dog draught excluder. It’s a great quick-fix to help prevent heat escaping under your door, and cold draughts from blowing in.

What about condensation?

It’s true that some people believe that turning the heating on and off throughout the day causes condensation in the walls, which leads to extra heat loss. But we haven’t seen any clear proof of this.

I’m still not convinced – how can I test this theory?

It’s simple. Pick a time when you know you’ll be around for 2 weeks, and on your normal work/home schedule:

  • Start by taking a meter reading – from the gas meter if you have a gas boiler, or the electricity meter if you use night storage heaters or electric underfloor heating.
  • For the first week, leave your heating on all the time, at a comfortable temperature.
  • At the end of the week, take another meter reading.
  • For the second week, set your timer and thermostat so your heating goes on and off, so it only heats your home when you need it. Make sure it’s still at a comfortable temperature, so as not to skew the results.
  • At the end of the week, take a meter reading.

Your last meter reading should clearly show that you’ve saved money by switching your heating off when you don’t need it. But whatever the result, you’ll certainly have worked out the cheapest way for you to heat your home.

Which parts of my home can I insulate?

You can insulate your home’s walls, roof, windows and doors – and of all the things you can do to save energy and reduce your bills, this is the most impactful.

For more ways to cut your energy use, see our handy guides:

What’s the best way to insulate my home?

These are our favourite ways for preventing heat loss:

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 recently launched Green Homes Grant.

How can I improve the energy efficiency of my heating system?

Unless your home is brand new, your heating system’s probably not as efficient as it could be. There are a few ways you can bring it up to scratch:

  • If your boiler is 15 years old or more, it could be time to change it for a younger, greener version. Replacing an old G-rated boiler with a new A-rated condensing boiler and a full set of heating controls, including the latest timer and thermostat, could make a big difference to your bills.
  • In the meantime, tweak your current boiler, with our guide to boiler efficiency and how to improve it.
  • If you have a system boiler, prevent heat loss from your hot water tank for longer by keeping it cosy in a cylinder jacket. You’ll waste less energy heating it, and you could save about £20 a year3.
  • Insulate any hot water pipes you can see in your home – i.e. not the ones in the walls, or under the floorboards. Pipes lose heat if they’re out in the open.
  • Get smart heating controls, so you can switch your heating and electricity on and off remotely. Then you can switch on the heating half an hour before you’re due to get home, or switch it off if you’re going to be home later than you thought. This is probably the most cost-effective way to use central heating.

For more ideas, see our guide to making your home more energy-efficient

And if your boiler stops working, read our practical guide on common boiler problems and how to fix them.

Top 5 most efficient or cheapest home heating options 

1. Storage heaters

While older models may be inefficient, newer storage heaters are much improved – so investing in a new one 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.

These will save you even more money 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 12am-7am). 

2. Air source heat pumps

Air source heat pumps are a greener alternative to a boiler. They work by absorbing heat from the air outside, using it to heat your home and give you hot water.  

While they do require an upfront cost, they can offer great benefits in the long run. They’re powered by air – a wonderfully renewable energy source – rather than fossil fuels, and they can save you money on your bills. Installation costs range from £5,000 to £8,0004.

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

3. Ground source heat pumps

Another alternative to a traditional boiler, ground source heat pumps are similar to their air source relatives. They draw heat from the environment surrounding the house, usually via pipes buried in the garden, which draw heat from the ground.

They circulate a mixture of water and antifreeze around a loop of pipe, absorbing heat from the ground into the fluid, which is then passed into a heat exchanger in the pump.

Like air source heat pumps, they also require an upfront cost – but they can reap rewards in your carbon use and energy bills. Installation costs range from £11,000 to £15,0005.

Want to know more about ground source heat pumps? We've got a quick and easy guide that gives you all the details.

4. Hybrid heat pumps

Combining a traditional boiler with an air source heat pump, a hybrid heat pump system automatically switches between the 2, to give you the best energy-efficiency. This is a good stepping stone from a traditional system to a more environmentally-friendly one.

5. Solar thermal panels

You’re probably familiar with solar panels – but did you know there are special solar thermal panels especially for turning sunlight into heat? 

Solar thermal systems use free heat from the sun to warm hot water. 

They’re actually even more efficient than traditional solar panels, as heat waves carry more energy than sunlight. Plus, there’s no transformation process needed to turn that energy into electricity.

On average, a solar thermal system creates as much as 60% of your hot water, and can help you save up to 600 kg of carbon emissions in a year6. That’s equivalent to the carbon taken out of the atmosphere by 10 trees over a decade!

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

Other FAQs on how to save energy in winter 

Should I keep the hot water boiler on all the time, or turn it on and off as needed?

 This really depends what type of system you have. If you have a gas, oil or liquefied petroleum gas (LPG) system, we recommend using a timer, so that it’s 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? 

Not necessarily. But they could certainly help! In place of traditional gas and electricity meters, smart meters measure your usage and automatically send readings to your supplier. This by itself won’t mean you save any money – but the smart meter display can help you track your energy use, and help you see where to use less energy where it’s not needed.

If you want to go a step further, check out smart thermostats. They can help you 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 run appliances at night?

In terms of saving money, this only matters if you’re on a time-of-use tariff, such as Economy 7. If you’re on one of these tariffs, you’ll pay less during the night, but more than average during the day.

The only other thing to think about is safety. Make sure you’re not risking any hazards by leaving appliances plugged in and unattended!

Should I set the thermostat on individual radiators, rather than using the main thermostat to control all of them?

Our general motto for heating systems is: the more control, the better! So using radiator valves to adjust the temperature of individual radiators is always a good idea. This means that 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 is the difference between controlling the heating using the thermostat or radiator valves? 

In essence, radiator valves control the heat of the radiator they’re connected to – while thermostats control a larger area of the home. 

If you’re trying to decide whether it’s better to use your radiator valves or your thermostat to control the heating, there are a few things to consider:

  • Do you have multiple thermostats? If the answer is yes, then you may have less need to use radiator valves. This is because the different thermostats will enable you to adjust the temperature in different parts of the home.
  • If you just have one thermostat for your entire home, there could be great advantages to using radiator valves, as well as your thermostat. You can set the thermostat to around 20 or 21°, then adjust the radiators in particular rooms to suit your needs.

If my heating is on, should I keep doors open or closed for each room?

We’d recommend keeping them closed. Most heating systems work by creating a ‘convection current’ in a room. This means that hot air rises, moves round the room, sinks down, and travels back to the heater to be warmed up once more

Radiators, electric panel heaters and convection heaters all work by creating a convection current in a room. As hot air rises, it circles around to the other side of the room, cools, sinks and travels along the floor to the heater, where it’s warmed up once more. Closing the door means this cycle isn’t disturbed, so the room stays nice and cosy!

Would painting my radiators black or putting reflective panels behind them help?

When it comes to painting your radiators black, this is one unconventional suggestion that just doesn’t work. Similarly, radiator panels can save energy, but not very much. 

Is a combi boiler cheaper to run? 

Whether a combi or a regular boiler is cheaper to run will depend on your lifestyle, and how much hot water you use7. Standard boilers heat water and keep it in a tank for when you need it, while combi boilers heat up water instantly.

  • For small households that don’t use a lot of water – a combi boiler could be the best choice, as hot water won’t be left to go cold in the tank
  • For large households that use a lot of water – a regular boiler with a well-insulated tank could be the better option, as combi boilers tend to be less efficient at heating water

Either way, having the most efficient boiler possible makes a huge difference. Aim for an A-rated condensing boiler if possible.

Still have questions on which is the best boiler for you? We've done the hard work for you, and put together a quick guide on the different types of boiler and how to choose the right one for you

And if you're considering buying a new boiler, why not get a quote to find out costs, and how much you might be able to save?

Should you leave your heating on if you’re going away? 

Frozen pipes can cause hundreds of pounds of damage – so it’s definitely recommended to time your heating to be on to some degree, even if you’re going to be away.

We’d recommend checking your home insurance policy before you go. Often they’ll ask that heating is kept to a minimum of 12 degrees.

And if you’re after a smarter, hassle-free solution, how about getting a smart thermostat? You’ll be able to control your heating from your phone wherever you are, so that everything’s just right whether you’re returning home from a holiday, or a day at work. Find out more about smart thermostats and our partnership with tado°.

With OVO you could enjoy more than just cheaper bills. We’re setting our sights on helping save the planet.

If you want to lower your carbon footprint, we have all the green energy and tech you need to do it. Why not join us on the journey to zero carbon?

Check our range of plans and see how much you could save.

Sources and references:

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

2 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.

3  https://energysavingtrust.org.uk/advice/insulating-tanks-pipes-and-radiators/#:~:text=It%20should%20be%20at%20least,the%20cost%20of%20the%20jacket

4  https://www.renewableenergyhub.co.uk/main/heat-pumps-information/a-guide-to-heat-pump-prices-in-2019/

5  https://www.renewableenergyhub.co.uk/main/heat-pumps-information/a-guide-to-heat-pump-prices-in-2019/

6  https://www.greenmatch.co.uk/solar-energy/solar-thermal/solar-thermal-panels

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

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