Underfloor heating (UFH) has gone from a luxury feature to a popular choice in UK kitchens, bathrooms, extensions and new builds. It gives even, comfortable warmth, frees up wall space and works especially well with heat pumps. It isn’t right for every home or room, though. Installation can be disruptive, some systems are slow to warm up, electric systems can be expensive to run, and your choice of flooring makes a big difference to performance.
This guide covers the pros and cons of underfloor heating: how it works, wet vs electric systems, installation and running costs, retrofit options, warm-up times, flooring compatibility, heat pumps, controls and the rooms where it works best.
Table of Contents
How Underfloor Heating Works
Underfloor heating warms the floor, which then radiates heat evenly into the room. The Energy Saving Trust explains that as the heat radiates from the floor, the heat enters the room evenly and provides a consistent temperature.
The Two Main Types
| Type | How It Works | Best For |
|---|---|---|
| Wet (water/hydronic) | Pipes under the floor carry warm water from a boiler or heat pump | Whole homes, extensions, new builds, large rooms |
| Electric (dry) | Heating mats or cables under the floor | Bathrooms, small rooms, renovations |
The Energy Saving Trust describes wet systems: Wet underfloor heating systems have a series of pipes laid underneath the floor. These pipes connect to the heating source (eg a heat pump or boiler), which sends warm water through the pipes, heating the space above.
For electric systems: Dry underfloor heating systems are made up of electric heating mats or cables that are laid underneath the floor. They generate heat when electricity is fed through them, which then heats the space above.
Pros of Underfloor Heating
1. Even, Comfortable Heat
Underfloor heating spreads warmth across the whole floor, avoiding hot and cold spots. The Energy Saving Trust lists the main benefits as having a consistent temperature in your rooms and a nice, cosy feeling underfoot.
2. Frees Up Wall Space
Without radiators, you have more freedom to arrange furniture, kitchen units and glazing. The Energy Saving Trust notes there’s no need for radiators which take up wall space, and it helps avoid furniture or curtains blocking heat distribution.
This is especially useful in kitchens and extensions with lots of glazing and units.
3. Energy Efficiency (Wet Systems)
Wet UFH runs at lower water temperatures than radiators because it has a much larger heating surface. The Energy Saving Trust explains: With a larger surface area than radiators, you can heat your home with ‘wet’ underfloor heating system at lower boiler or heat pump flow temperatures. This will help save money on your energy bills compared to only using radiators.
4. Perfect Partner for Heat Pumps
Heat pumps work most efficiently at low flow temperatures, which suits underfloor heating perfectly. The Energy Saving Trust says that with underfloor heating, the flow temperature could be lower compared with radiators, and this should result in the heat pump running much more efficiently.
Selectra puts it simply: A heat pump is at its most efficient when it only has to make low-temperature water, which is exactly what a heated floor wants.
5. Warm Floors in Bathrooms and Kitchens
Warm tiles underfoot are a big comfort upgrade, especially in bathrooms. Stone and ceramic floors work well because, according to the Energy Saving Trust, these transfer heat efficiently so are a good option for underfloor heating systems.
6. Quiet and Low Maintenance
Wet systems have few moving parts in the floor itself, and pipes are designed to last for decades. Electric systems have no moving parts at all.
7. Can Add Appeal and Value
Underfloor heating is often seen as a premium feature by buyers, especially in kitchens, bathrooms and extensions.
8. Better for Allergies
Underfloor heating creates less air movement than radiators, which can mean less dust circulation.
Cons of Underfloor Heating
1. Higher Installation Cost
Underfloor heating usually costs more to install than radiators, especially wet systems in existing homes.
2. Disruptive Retrofit
Installing wet UFH in an existing home often means lifting floors, adding insulation and screed, and raising floor levels. This is far easier during a renovation or extension.
3. Slower Warm-Up Times
Screed-based systems warm up slowly. Selectra explains that warm water runs through the pipes, the screed heats up, and only then does the surface start giving heat to the room. The concrete has to warm before the room can, and that mass works against you in both directions.
Warm-up time depends on the system build-up. One expert explains that if pipes are housed in a thick concrete slab, the time taken to warm the room will be well over four hours, while a thinner flow screed of 35mm to 40mm would bring the reaction time down to 30 to 40 minutes, which is similar to a radiator system.
Electric systems are faster. One supplier notes that an electric underfloor heating system can achieve maximum heat output within 30-60 minutes.
4. Electric Systems Are Expensive to Run
Electric UFH can be costly over large areas. The Energy Saving Trust compares electric UFH to direct electric heaters, noting they rely on using electricity directly, and can be expensive compared to other heating options.
Trade2Base explains that running costs are considerably higher than wet UFH because electricity costs roughly four times as much per kWh as gas (and twice as much as a heat pump running on electricity), so electric mats are not suitable as whole-house heating.
5. Flooring Restrictions
Thick carpets and some wood floors reduce heat output. You’ll need to check that flooring is suitable for UFH.
6. Furniture Placement
Large items without legs, such as divan beds, can trap heat. Selectra warns about divan and ottoman beds, which cover several square metres in a bedroom, and notes that furniture on legs lets warm air move.
7. Repairs Can Be Disruptive
If pipes or cables are damaged, repairs may mean lifting the floor. Damage is rare with good installation, but avoid drilling into heated floors.
Wet vs Electric Underfloor Heating
| Factor | Wet (Water) UFH | Electric UFH |
|---|---|---|
| Installation cost | Higher | Lower |
| Running cost | Lower | Higher |
| Best for | Whole homes, extensions, large rooms | Bathrooms, small rooms, renovations |
| Warm-up time | Slower (screed-based) | Faster |
| Floor height increase | Larger | Minimal |
| Works with heat pumps | Yes, ideal | No (uses electricity directly) |
| Installation complexity | Plumber/heating engineer; manifold needed | Electrician; simpler |
| Lifespan | Very long | Long |
Trade2Base summarises: Wet UFH costs more to install but is far cheaper to run, especially on a heat pump, and is the right choice for whole-house heating, new builds and extensions.
City Plumbing agrees: For heating a whole house or any frequently used area over 20 m2, Wet UFH delivers significantly lower long-term running costs and is the best value over the system’s lifetime.
Underfloor Heating Installation Costs in the UK
Cost per Square Metre
| System and Property | Average Installation Cost per m² |
|---|---|
| Electric in renovation | £60–£85 |
| Electric in new build | £50–£75 |
| Wet in new build | £85–£100 |
| Wet in renovation | £95–£110 |
These figures come from Checkatrade. Other sources give wider ranges. MyJobQuote reports that electric underfloor heating costs around £40 to £90 per m², while wet underfloor heating costs around £100 to £190 per m².
City Plumbing gives similar figures for wet renovation: Renovation: Typically £100 – £190 per m2.
Typical Project Costs
| Project | Typical Cost |
|---|---|
| Single room installation (average) | Around £900 |
| Electric UFH whole-house installation | Around £4,000 |
| Wet UFH whole-house installation | Around £8,000 |
MyJobQuote reports that the average underfloor heating installation cost is around £900, and that most underfloor heating installers can fit a single room in 1 to 2 days. Checkatrade gives whole-house estimates of Wet based underfloor heating installation£8,000 and Electric underfloor heating installation£4,000.
Hidden Costs
- Floor insulation
- Screed or overlay boards
- Manifold and pump (wet systems)
- Thermostats and controls
- Electrical connection and certification (electric systems)
- Lifting and replacing existing flooring
- Raising door thresholds and skirting
- New floor finishes
Note that some per-m² figures exclude screed. Plumbing Superstore notes that wet UFH in a new build can cost £30 to £50 per m², but this figure does not include the screed, which is extra.
Running Costs
Running costs depend on system type, energy prices, insulation, usage and controls.
Hourly Running Costs (Checkatrade/Jackery Estimates)
| Room | Electric | Wet |
|---|---|---|
| Small bathroom (5m²) | Around £0.12/hour | Around £0.07/hour |
| Lounge (20m²) | Around £0.49/hour | Around £0.26/hour |
Jackery reports that for electric systems, running costs range from £0.12 per hour for a tiny bathroom (5m²) to roughly £0.49 per hour for a 20m² lounge, while for wet systems running costs range from £0.07 per hour for a tiny bathroom (5m²) to roughly £0.26 per hour for a 20m² lounge.
Annual Running Costs by Room Size
| Room Size | Electric | Warm Water | Annual Saving (Wet) |
|---|---|---|---|
| 10m² | £623 | £184 | £439 |
| 20m² | £1,246 | £368 | £878 |
| 30m² | £1,869 | £552 | £1,317 |
These estimates come from Jackery’s comparison table. Actual costs depend heavily on usage, insulation and tariffs.
Whole-House Comparison
Checkatrade compares whole-house annual heating costs: Traditional gas boiler with radiators £1,916, Gas boiler with underfloor heating£1,916 and Electric under floor heating£2,646.
Why Electric Costs More
Fuse Energy notes that electric underfloor heating typically costs more to run than wet underfloor heating, often three to six times higher per kWh of heat generated.
Electric UFH can still be sensible in small rooms. Checkatrade notes that many households use electric underfloor heating in smaller rooms or on timers, which helps keep running costs manageable.
Calculating Electric UFH Running Costs
City Plumbing gives a simple formula: Annual Running Cost = (Area (m2) x Wattage (kW/m2) x Hours Used x Days Used) x Electricity Price (£/kWh)
Example: a 5m² bathroom with a 150W/m² system used 2 hours a day for 182 days at 27p/kWh:
- 5 × 0.15 × 2 × 182 × £0.27 ≈ £74 per year
Underfloor Heating and Heat Pumps
Underfloor heating is widely considered the best heat emitter for heat pumps.
| Heat Source | Typical Flow Temperature |
|---|---|
| Underfloor heating (heat pump) | Around 25–35°C |
| Oversized radiators (heat pump) | Around 35–45°C |
| Traditional gas boiler radiators | Around 55–75°C |
Selectra notes that for a 19–20°C room, a typical UFH flow temperature is about 35°C.
The Energy Saving Trust says that heat pump owners might benefit from larger radiators or underfloor heating because they have larger surface areas.
Mixed Systems
Many homes use UFH downstairs and radiators upstairs. The Energy Saving Trust notes that getting the right sized radiators will ensure enough heat is emitted in upstairs rooms, while keeping a suitable flow temperature for downstairs.
Running UFH With a Heat Pump
Don’t turn the flow temperature up to speed things up. Selectra advises: Pushing the curve up to speed things along costs efficiency without warming the screed any faster. Keep it low, start early, and let the slab do its work.
Heat Pump Grants
The Boiler Upgrade Scheme offers £7,500 towards air source and ground source heat pumps in England and Wales, which can make a heat pump with UFH more affordable. Check GOV.UK for current eligibility.
Best Flooring for Underfloor Heating
| Flooring | Performance | Notes |
|---|---|---|
| Stone and ceramic tiles | Excellent | Best heat transfer |
| Porcelain tiles | Excellent | Durable, good conductor |
| Polished concrete/microcement | Excellent | Good thermal mass |
| Engineered wood | Good | More stable than solid wood |
| LVT/vinyl | Good | Check temperature limits |
| Laminate | Good | Check compatibility |
| Solid wood | Fair | Can move; check suitability |
| Carpet | Fair to poor | Keep combined tog rating low |
Engineered Wood
The Energy Saving Trust explains that engineered wood includes a base layer that strengthens the wood itself and allows it to cope with the changes in temperature associated with underfloor heating. Thin boards work best: one expert notes that thinner profile (12mm or 15mm) engineered timber flooring has little noticeable impact on heat output.
Carpet and Tog Ratings
Carpet insulates, so check the combined tog rating of carpet and underlay. The Energy Saving Trust notes that Home Building & Renovating recommends that the tog rating is 2.5 or lower.
With heat pumps, aim lower. Selectra reports that tests by the Underfloor Heating Manufacturers’ Association found that carpet and underlay with a combined rating of up to 2.5 tog can work, and installers advise staying nearer 1.5 tog with a heat pump.
Floor Surface Temperatures
| Area | Maximum Floor Surface Temperature |
|---|---|
| Occupied areas | 29°C |
| Strips by outside walls | 35°C |
| Carpet | 27°C (typical maximum) |
Selectra lists Floor surface, occupied area 29°C maximum and Floor surface, strip by outside walls 35°C maximum. One supplier notes that an ideal floor surface temperature for most people is between 23°C and 27°C.
Retrofit Options
| Retrofit Option | Description | Floor Height Increase |
|---|---|---|
| Low-profile overlay boards | Pipes in grooved boards over existing floors | Small (around 15–25mm) |
| Electric mats | Laid under tiles or flooring | Minimal |
| Between-joist systems | Pipes fitted between timber floor joists | None, but floors must be lifted |
| Full screed system | Dig out and replace floor | Requires excavation |
Retrofit Considerations
- Floor height increases may affect doors, thresholds and kitchen units
- Insulation below the system improves efficiency
- Existing heat loss must be manageable
- Older, poorly insulated homes may need radiators too
Controls and Thermostats
Good controls are essential for efficiency and comfort.
- Room thermostats: each room or zone controlled separately
- Smart thermostats: remote control and scheduling
- Floor sensors: protect flooring from overheating
- Weather compensation: adjusts flow temperature to outdoor conditions (especially for heat pumps)
- Timers: pre-heat rooms before you need them
Because of slower warm-up times, smart controls help. One supplier suggests a smart thermostat, which can be conveniently controlled by your phone, so you can turn the system on before you get home.
Night Setback
With screed systems, avoid large temperature drops overnight. Selectra recommends a night setback of 2°C at most.
Restarting After Summer
Screed-based systems take time to warm up after months off. Selectra advises that restarting starts several days before the cold, and notes that a brand new floor is never fired up at full temperature.
Best Rooms for Underfloor Heating
| Room | Best System | Why |
|---|---|---|
| Bathroom/en suite | Electric | Small area, warm tiles |
| Kitchen | Wet or electric | Frees wall space for units |
| Extension/kitchen-diner | Wet | Large area, lots of glazing |
| Conservatory | Wet or electric | Warm floors in glazed spaces |
| Living room | Wet | Even heat, no radiators |
| Bedroom | Wet (watch carpet tog) | Comfort, but check flooring |
| Whole house (new build) | Wet with heat pump | Most efficient |
| Hallway | Wet | Warm entrance |
Is Underfloor Heating Worth It?
Underfloor Heating Is Worth It If:
- You’re building an extension or new build
- You’re renovating and lifting floors anyway
- You’re installing a heat pump
- You want to free up wall space
- You want warm tiled bathroom and kitchen floors
- Your home is well insulated
It May Not Be Worth It If:
- You can’t raise floor levels
- You need quick bursts of heat
- You want electric UFH for large, frequently used rooms
- Your home is poorly insulated
- You have lots of thick carpets
- You’re on a tight budget and radiators work well
Underfloor Heating Checklist
- Decide between wet and electric
- Check insulation levels
- Check floor heights and thresholds
- Choose compatible flooring
- Check carpet tog ratings (2.5 or lower; nearer 1.5 with heat pumps)
- Plan zones and thermostats
- Consider a heat pump and grants
- Get quotes from qualified installers
- Use an electrician for electric systems (bathroom work is often notifiable)
- Commission the system properly and follow warm-up schedules
Common Mistakes
| Mistake | Better Approach |
|---|---|
| Electric UFH for whole houses | Use wet systems for large areas |
| No insulation under the system | Insulate below to reduce heat loss |
| Thick carpets and underlays | Keep combined tog at 2.5 or lower |
| Turning flow temperature up for faster heat | Start earlier with smart controls |
| Divan beds over heated floors | Choose furniture on legs |
| Firing up new screeds too fast | Follow commissioning schedules |
| Poor zoning | Use room thermostats |
| Drilling into heated floors | Mark pipe and cable routes |
| Ignoring floor height changes | Plan thresholds and doors |
Final Thoughts
Underfloor heating offers even, comfortable warmth, frees up wall space and, with wet systems, can run at low flow temperatures that make boilers and especially heat pumps more efficient. The main drawbacks are higher installation costs, disruption when retrofitting, slower warm-up times for screed systems and high running costs for electric systems over large areas. In the UK, electric UFH typically costs around £50–£85 per m² to install and suits bathrooms and small rooms, while wet UFH costs around £85–£190 per m² and is the better long-term choice for extensions, new builds and whole homes. Choose conductive flooring such as tiles or engineered wood, keep carpet and underlay at 2.5 tog or below, and use good controls to get the best from your system.
Frequently Asked Questions
1. Is underfloor heating cheaper to run than radiators?
Wet UFH can be cheaper to run because it works at lower flow temperatures, especially with a heat pump. Electric UFH is usually more expensive to run.
2. How much does underfloor heating cost in the UK?
Electric UFH costs around £50–£85 per m² to install, while wet UFH costs around £85–£190 per m² depending on the project.
3. Can you put carpet over underfloor heating?
Yes, but keep the combined tog rating of carpet and underlay at 2.5 or lower, and nearer 1.5 tog with a heat pump.
