Underfloor heating: how it works and how much it costs to buy and run
19 November 2021 | Stephen Marcus
It’s not hard to see the appeal of underfloor heating. After all, who wouldn’t want to make the winter months more cosy, from your feet upwards? Plus, if you opt for it throughout the house, it can even remove the need for radiators. That means more space for shelving, furniture, artwork, or even a bold new minimalist look!
This guide will tell you everything you need to know about:
What is underfloor heating?
Simply put, underfloor heating warms your home through a system installed beneath your flooring – as opposed to the radiators most of us are familiar with. Aside from the wonderful feeling of having warm floors, it distributes heat very evenly through your home.
For more ogn lowering your energy use, check out our ultimate guide to being efficient with heating and hot water.
How does underfloor heating work?
Heating tubes or cables are installed beneath your floor. Flexible tubes are heated by hot water in a "wet" system, or cables are heated by electricity in a "dry" system. Because these tubes or cables cover the whole surface area of your floor, it's like creating a giant radiator under your floorboards! This means much lower temperatures are needed to heat your home, which also improves efficiency. And no more cold spots!
Advantages of underfloor heating
Here are some of the top perks of underfloor heating:
- Toasty warm feet! You can walk around barefoot all year. Making stepping out of the bath or shower heavenly!
- It distributes heat evenly and consistently around each room.
- A suitably-sized unit can heat a larger area than an individual radiator, and works at a lower temperature, so it could reduce your heating bills.
- Less waste – your floors will stay warm, even if the windows are open or the room is draughty.
- It’s hidden – so it doesn’t spoil your décor or take up space with bulky radiators. (But if you do want to get your radiators working at their best in the meantime, check out our guide on how to bleed a radiator.)
- It can be installed below stone, tile, wood, or carpeted floors (as long as the carpet isn’t too thick – a 1.5 tog is generally considered the maximum suitable thickness).
- It can make your home more hygienic – a warmer floor temperature is inhospitable to dust mites. So you’ll have warmer feet and fewer creepy crawlies!
Disadvantages of underfloor heating
- The main problem with underfloor heating is the cost. It can be expensive, and difficult to install – so even if your bills are lower, you’re unlikely to make up for the money you spent.
- In older buildings, adding underfloor heating can take time and cause major upheaval.
- It can take a long time to warm up – so it’s vital to use a timer, to make sure your rooms are warm enough when you want to use them.
- You can’t use it under some items of furniture or fittings. In fact, if you want to install underfloor heating, you might have to get rid of some large, heavy items altogether.
- If you use a smaller system, you may find you have a lovely warm floor but the rest of the room is still chilly – meaning you’d need radiators anyway.
What are the different types of underfloor heating systems?
There are 2 main types of underfloor heating systems – warm water, or “wet” underfloor heating, and electric, or “dry” underfloor heating. Take a look at this table1 to compare them:
|Underfloor heating system||Suitability||Installation costs||Running costs||Installation time|
|Wet, or water system||Suitable for all types of home, from renovations to new builds and single rooms||High upfront cost||Low long-term running costs||Depends on the size of project and type of system|
|Dry, or electric system||Best for smaller spaces like bathrooms, due to the higher running cost||Lower upfront cost||Around 3 times more expensive to run than wet systems||A single room can be installed in just a few hours|
Electric, or "dry" underfloor heating
As the name suggests, an electric system uses electricity to warm your floors via heating cables fitted underneath. There are three choices for ‘dry’ systems:
- Loose wire – best suited for stone or tile floors, and ideal for awkward-shaped rooms
- Matting – great for stone or tile floors, and for large or more regular-shaped rooms
- Foil mat – designed specifically for laminate flooring
Water, or “wet” underfloor heating systems
Wet systems connect to your central heating system via a network of pipes running hot water beneath your feet. Here’s the basics:
Can be used with any kind of boiler, as long as it has enough capacity
The water is pumped through pipes laid on to a sub floor (a floor underneath your floor), before the new surface is added on top
The system uses continuous plastic pipes, so there are no joints – which means no leaks!
Which type of underfloor heating is best?
It’s generally agreed that wet underfloor heating systems are the best because they’re more effective, more efficient, and cheaper to run. Pipes that hold the hot water are attached onto an insulation layer, then the screed (a concrete-like material) is poured over the pipes and sets hard.
The warm pipes heat up the whole slab, which gives a consistent and even warmth.
How much does underfloor heating cost?
There are 2 things to consider here: how much underfloor heating costs to install, and how much it costs to run.
Costs to install underfloor heating
Underfloor heating costs depend on various factors:
- The type of underfloor heating system you choose
- The size of your room
- The age of your building
Here’s a table2 that can give you a rough idea of how much you can expect to pay for the different types of underfloor heating in old and new homes:
|Type of underfloor heating||New or renovated||Material cost||Labour cost||Completion time||Total cost|
|Electric||Renovated||£3600+||£480 - £720||2 to 3 days||£4000 - £4500|
|Electric||New build||£2100+||£240 - £480||1 to 2 days||£2300 - £2600|
|Water||Renovated||£9000+||£1200 - £1680||5 to 7 days||£10,000 - £11,000|
|Water||New build||£4800+||£960 - £1440||4 to 6 days||£5500 - £6500|
As you can see, it’s almost always cheaper to install a dry system. Prices for roll-out mats for underfloor electric heating start at about £170 for 10 square metres2. Plus, you’ll need to add in the costs of insulation board, screed, and heating controls. You’ll also need to pay a qualified electrician to link it to your electricity supply.
The price of installing a wet system can vary. If it’s just one room, then it depends on whether it’s on the ground floor, or how close it is to the boiler. It will almost certainly be more expensive than installing an electric system. But, if you read on, you’ll see that it’s cheaper to run.
How is underfloor heating installed? Can I install it myself?
If you’re confident with DIY, then it’s possible to install an electric system yourself – but if you’ve opted for a water system, you’ll need to hire a professional.
For either system, an electrician would need to connect both your system to the electricity supply, and a sensor for the thermostat. For this reason, it’s wise to have a professional install underfloor heating.
Do I need to install additional insulation with underfloor heating?
Improving your home insulation is one of the most effective ways to keep your home warm and reduce your energy bills. If you’re thinking about installing underfloor heating, we’d recommend you improve your insulation first, as it means the system will be able to work more efficiently and effectively.
How much does underfloor heating cost to run?
In most cases, there’ll be a big difference between the heating costs of a wet and dry system.
Warm water underfloor heating running costs
While it might be expensive to install, “wet” underfloor heating is usually the cheaper option to run. It’s typically more efficient than an electric system, meaning that you can run it for less.
Electric underfloor heating running costs
“Dry” systems can be a lot more expensive to run. This is largely due to the fact that electricity tends to cost more than natural gas. For this reason, it’s often used to heat single rooms, like bathrooms or kitchens.
Is it cheaper to leave underfloor heating on all the time?
In colder months, it can work out cheaper to leave underfloor heating on at a low temperature throughout the day, because of the time it can take to warm up.
What type of flooring is best for underfloor heating?
As you might expect, stone materials are best-suited to underfloor heating – as they’re natural heat conductors, warming up more quickly and keeping the heat for longer. But it’s possible to use most types of flooring, including vinyl, laminate, and tiles.
Whichever type of flooring you’re after, it should be possible to arrange your system to suit your needs. Here, we go through some of the key things to consider.
Real wood floors need extra care. It’s worth checking the maximum temperature the wood can handle with the manufacturer. It’s usually around 27C. Anything above that, and the heat can cause the wood to warp and shrink.
Engineered or laminate floors can be a good option for a wood feel without the risks. The only thing to bear in mind is to ensure it’s not too thick – ideally no more than 18mm – otherwise it will affect the efficiency of your system.
To get the best results with carpet, you don’t want it to be too thick. The thicker the carpet, the longer it will take to warm up. For this reason, the combined tog of the carpet and underlay should be below 2.5.
For many, concrete is the perfect flooring for a sleek, modern interior. And the good news is that it’s well-suited for underfloor heating, because it holds heat for a long time.
One important thing to remember is to avoid sealing the underfloor heating system itself in concrete. Both water and electric systems should be installed within screed, not the concrete, which can damage the system.
How long do underfloor heating parts and components last for?
The pipes used in underfloor heating systems have an average lifespan of around 50 years. Which, compared to a radiator’s projected 10 to 12 years, is good going3.
Is underfloor heating better than radiators?
Underfloor heating is like turning your whole floor into a radiator! But the key difference is that underfloor heating is much more efficient. Why? Because the underfloor heating system covers such a large surface area, it doesn’t have to be heated to such a high temperature as radiators to warm the room.
Keeping your underfloor heating system just a couple of degrees warmer than normal room temperature can use 15 to 40% less energy than traditional radiators4.
What’s the ideal temperature for underfloor heating?
As ever, this varies depending on your home and your preferences – but for most people the ideal temperature is around 21°C for living areas, and 18°C for bedrooms. Check out our handy infographic to get a better idea of the perfect temperature for each room of your home.
FAQs about installing an underfloor heating system
Underfloor heating is actually safer and healthier than radiators, because there are no exposed hot surfaces and no dust traps. Plus, because of the constant, comfortable heat source, they help eliminate cold spots.
This all depends on the type of system you install. Screed underfloor heating is usually consistently left on a low temperature. This helps the concrete slab to store the heat and avoid long heat-up times, keeping running costs low. Retrofit underfloor heating, on the other hand, can heat up and cool down quickly, so it can be controlled more like a radiator system.
No, it’s not necessary to dig floors up. There are various systems and installation options available, including low-profile solutions that can be laid directly over existing solid or timber floors.
Underfloor heating will usually raise the profile of the floor. But the amount it’s raised by depends on various factors, including:
- How much insulation you need
- Pipe size
- If you need a screed and floor finish
You can also get some underfloor heating that can be carved into existing screed, so you’d only need a final floor finish on top. A low-profile system would be a good option, as they can be installed fairly quickly and easily without raising your floor profile too much.
If you’re adding an underfloor heating system to your existing system, you’ll need a separate thermostat.
Yes – but it’s worth considering if it’s the best option. If you have an old house with poor insulation, or single glazing, it will probably still need to be combined with a traditional radiator system.
If your home has low energy efficiency, and you still want to install underfloor heating, it could be worth doing alongside renovation work such as installing insulation, and energy-efficient doors and windows.
You could also think about DIY insulation quick-fixes such as making your own sausage dog draught excluder. Taking these types of steps would all help to bring down the cost of running your system.
For more information about insulation, check out the wide range of guides and tips on our content hub.
Unless you’re lucky enough to live in a listed building or historically significant property, the answer is probably no. If it’s going into a new room, then you’ll need to make sure you follow building regulations.
Depending on your flooring and the kind of system you have, it can take 2 or 3 hours to warm up. This is because the screed around the heating pipes takes a while to conduct the heat up through the floor and warm the air.
Ideally, yes. You’ll need to set it to come on a good while before you need it.
Have you thought about smart thermostats? They can help you control your heating from anywhere, while also reducing your bills. Read our guide to find out more about the benefits of smart thermostats and why you should get one.
How else can I make my home warmer?
Insulation is key. Insulate your roof and walls and you could save around £250 a year3. What’s more, it’ll cut your carbon emissions too, which is great news for the planet.
Some other top tips include:
- Fill your walls! Cavity wall insulation can cut around £115 off your heating bill each year4.
- Get draught excluders for outside doors, windows and letterboxes.
- Replace all your old windows with double glazing – it could save you around £120 each year5.
- If your boiler’s more than 15 years old, look into replacing it with a new A-rated condensing boiler. Check out our practical guide to help you choose the right boiler for you.
How can I cut my energy costs?
Underfloor heating installation can be expensive – so you may want to find other ways to save on your energy bills. To start with, make sure your home and all your electrical appliances are working as efficiently as possible. Here are 120 more ways to save energy around your home.
See our full guide to energy-saving for more details, our explainer on how to use your heating efficiently during the winter, and our guide to working out how much energy you use for heating.
Switch energy suppliers
It also makes sense to consider switching suppliers. No matter which energy company you’re currently with, we recommend you check the market regularly to see if you could save money by switching. You can get a quote on a plan with OVO in seconds.
See how your current supplier matches up next to our range of energy plans. Compare prices for our electricity, gas and dual fuel plans.