Installing underfloor heating, particularly a water system in an existing room, can be expensive and messy. But it can also be a great way to take the chill off a cold bathroom floor or potentially heat a room without the need for radiators.
In this guide, we explore the upsides and downsides of installing underfloor heating according to people who've had it installed, and offer expert advice on where it can be installed and whether electric or water underfloor heating would work better in your home.
Underfloor heating is a modern and high-spec feature that allows you to enjoy the luxury of warm floors during cold winter mornings, particularly if you have naturally cold stone or tile floors.
But installing it involves considerable expense and upheaval, so there are some things you need to weigh up to decide whether it's right for you. We'd suggest thinking about your lifestyle and how you use your home. Are you mainly in the kitchen, or maybe always in late after work?
These sorts of things will affect how much you'll actually use underfloor heating (and therefore whether it's worth getting), what room or rooms it makes most sense to have it in, and how you will need to set the timings to suit your needs.
Nobody knows the upsides and downsides of a product better than those that are already using it. So, we asked more than 100 Which? members* who've had underfloor heating installed what they love about it – and what they wish could be better.
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Below, we've answered some of the most common questions about underfloor heating. Which? members can log in to get extra insights from homeowners who've already had underfloor heating installed.
You can get underfloor heating fitted in pretty much any home – either when it's being built or by retrofitting it into an existing property – and under almost any type of flooring.
Underfloor heating can be tailored to your needs, the room it will sit in and the flooring type, so that you get the right heat output for your home.
Many of the owners we've spoken to said they got underfloor heating because they were renovating their house, so it made sense to have it done while work was being carried out. Others had it built into a new extension or conservatory.
As you might expect, bathrooms are the most popular room for underfloor heating to be installed. We found that:
Underfloor heating also allows you to have different 'zones' (areas of heating) that you can control independently.
Zones can be separate rooms, or even different areas of a large room (a kitchen-diner, for example). This is useful if you know you will be in one 'zone' a lot more than others, or at certain times.
As is often the case, there's no categorical answer to this; there are pros and cons to both types of underfloor heating. The best type for you will depend on factors such as:
As a general rule, typically requires more space for the pipes so may mean floor levels in existing rooms needs to be raised, and is more complex and costly to install, but is likely to be cheaper to run once its in place. heating is more expensive to run, but tends to be easier and cheaper to fit. Competent DIYers can even install some systems themselves, although you'll need to hire a qualified electrician to connect it to your electricity supply.
Most (62%) of the people we asked who have underfloor heating have an electric system, while 38% have a water system.
Our tables below give an at-a glance comparison of the pros and cons of electric and water underfloor heating.
|Lower upfront costs than water underfloor heating||Higher running costs than water, so best for small areas such as bathrooms|
|Quicker to warm up than water systems||Cools down more quickly after it's turned off|
|Easier to install than water, and takes up less space so less likely to impact floor levels|
|Lower running costs than electric systems, so better for large areas||Higher upfront costs|
|Slower to warm up than electric systems||Pipes retain heat for longer after heating is turned off|
|Integrates well with sustainable heating systems, such as heat pumps||Complex to install; may require floor levels to be raised to make space for pipes|
Some off-the-shelf products are available for competent DIYers to fit. However, this is better suited to , especially if you buy it as mats with the wires attached, rather than loose wires. can be more complex to install, so is usually best done by a professional installer.
If underfloor heating isn't fitted correctly, there is more of a risk of a fault occurring – and you don't want to discover this after you've already laid the flooring on top. To avoid this, make sure you follow the supplied manual and test the system before it's covered.
If you damage an electric system during installation, you can buy repair kits for around £20 that may help fix it, depending on the nature and scale of the damage.
Employing a professional to install underfloor heating will cost more upfront, but also means they're responsible for dealing with any problems that do occur. Trade association BEAMA stresses the importance of selecting a suitable installer. It says: 'A professional will take the time to correctly size the system, taking into account the floor covering and the necessary type of controls. Before leaving they will then take time to explain to the customer how to use the system.'
If you'd prefer to get a professional in to install your underfloor heating, use our Which? Trusted Traders search tool below to find an installer that's been vetted and approved by Which?. You don't have to be a Which? member to use Which? Trusted Traders.
Although you can have underfloor heating fitted in most places, it might mean a lot of upheaval, especially if it's being fitted retrospectively to an existing room.
If retrofitting in an existing room, the current flooring will usually need to be taken up, which may damage or destroy it in some cases. And the floor height might need to be raised, which may mean you need to reduce the height of the door to compensate. Plus, if this causes a disparity in floor height between one room and the next, you may need to put in a half-step between rooms.
Many people choose to have underfloor heating installed at a time when they're carrying out other refurbishments, to keep disruption and costs to a minimum.
Although you can have underfloor heating fitted in most places, it might mean a lot of upheaval and high costs, especially if it's being fitted retrospectively to an existing room.
The exact cost of the system itself will depend on the size of the space and how well it's insulated. Larger rooms or those that aren't insulated might require bigger systems or ones with higher wattages, which will cost more.
Plus, there are expenses to consider above and beyond the cost of buying and laying the underfloor heating itself. If retrofitting in an existing room, the current flooring will need to be taken up, which may damage or destroy it in some cases. And the floor height might need to be raised, which will affect the door and ceiling height. All of this will mean more work for the installer, which adds to labour costs.
Our guide to details more on this, but we recommend speaking to a heating engineer as a first port of call, to decide whether the work and cost of underfloor heating will make it prohibitive for your home.
Running costs for underfloor heating depend on many of the factors we've mentioned above: how many rooms it's in, the insulation of the room and floor, the size of the room, whether it's replacing radiators and, of course, how much you have it switched on. Electric underfloor heating in particular can be quite expensive to run (water systems tend to be cheaper to run), so it's worth bearing this in mind before having it installed.
As with central heating systems, you can get a programmable thermostat for your underfloor heating. This will enable you to turn it on and off exactly when you need it, as well as changing the temperature, so you can maximise the efficiency and keep running costs down.
It also means you can control it separately from your central heating. In fact, each room with underfloor heating can have its own thermostat, giving you ultimate flexibility. This enables you to adjust just one room at a time to fit your needs and lifestyle, so heat isn't wasted when it's not needed.
If you like simplicity, get a streamlined thermostat with simple on/off controls. Or if you're into high-tech features, there are touchscreen or smart versions with lots of options, and which let you control the system from your smartphone.
Potentially. Replacing bulky radiators with underfloor heating can free up space and give a cleaner decorative finish.
However, if you want to use underfloor heating as a room's primary heat source, there are a few things to bear in mind.
It's worth keeping in mind that you will probably need to run the system at a higher temperature than if you were using it with another heat source.
If it's not possible to meet the criteria above, you may need additional heat, such as a heated towel radiator or plinth heater, for really cold days.
Smaller or less powerful systems will keep your floor warm, but won't necessarily heat up the rest of the room, especially if the wattage is lower or it's a room with external walls and the weather is very cold outside.
If you live in an old property with solid walls and not a lot of energy-saving measures – such as no loft insulation and/or single-glazed windows – it's unlikely that underfloor heating will be sufficient to heat a room on its own.
Many of the underfloor hearing owners we asked said it wasn’t a total replacement for radiators and that they had to use a second heat source if they needed heat quickly.
It depends on a number of factors. Compared with radiators, underfloor heating is more consistent, so is theoretically more efficient. But that doesn't mean it's less costly. This is in part down to the fact that most people have electric underfloor heating, and the high cost of electricity compared with gas (which most people use to heat radiators) makes electric underfloor heating comparatively pricey to run.
You'll also need to keep in mind a number of factors that can determine how efficient underfloor heating is, such as:
Underfloor heating systems are generally slower to heat up than radiators. If installed correctly, underfloor heating can take from 30 minutes to one hour to warm up.
This could be an issue if you need immediate warmth in a room. If you have a programmable thermostat, you can use this to set your underfloor heating to warm up before you're going to be using the room.
Electric underfloor heating systems typically have faster heat-up times than water, but water tends to give a more constant heat.
How quickly the heat is distributed depends to some extent on the floor covering and insulation.
You can speed it up by using flooring that will conduct heat easily, such as tiles.
Some floor types will also hold heat for longer, even after the system is turned off. For example, stone will retain heat for longer than vinyl flooring. Making sure your underfloor heating is fitted evenly, and on sufficient insulation boards, will also help to spread the heat more quickly.
When we spoke to underfloor heating owners about their experiences, there were a few niggles that cropped up more than once.
If you're thinking of installing underfloor heating, you may have concerns about the risk of something going wrong with the system, or needing to replace it after a number of years.
In reality, underfloor heating systems are more likely to be broken during installation than in day-to-day use.
They rarely fail during normal working conditions, particularly electric systems, as they're safely encased by insulation, screed and flooring.
If a fault does occur, especially if you're not sure where the damage has occurred, you will need to contact a specialist engineer to repair your underfloor heating.
These engineers can pinpoint faults under a finished floor to within a few millimetres. This means they can then excavate a tile or section without having to lift the entire floor.
For water underfloor heating, faults can be identified by using a thermal camera or a moisture tester.
It's also worth keeping in mind that if a failure does occur, some companies provide warranties and guarantees, so can assist with fixing any problems. Make sure you look out for this when you buy. Some offer lifetime guarantees and/or cover accidental damage as well as systemic failures.
For added peace of mind, employ a qualified installer and check that the components they use are built to a set standard.
* In December 2021 we surveyed 119 Which? members with underfloor heating about their experiences with it in the past five years.