Underfloor Heating in London -- Installation Costs, Types and What to Expect
Wet UFH costs more upfront but runs cheaper long-term. Electric UFH is quicker to install. Here's how to choose and what it costs in London.
Side by Side
Wet vs Electric Underfloor Heating
Both types heat your floor from below -- the difference is how they do it and what that means for installation cost, running cost and disruption.
| Feature | Wet (hydronic) UFH | Electric UFH |
|---|---|---|
| Installation cost (per m2) | £80-£150 | £50-£100 |
| Running cost | Low (uses boiler) | Higher (uses electricity) |
| Best for | New builds, renovations, whole house | Single rooms, retrofitting under tiles |
| Floor type | Screed, suspended (with boards) | Most floor types |
| Boiler needed | Yes (compatible with combi if sized correctly) | No |
| Installation disruption | High (floor lifted, screed poured) | Lower |
| Payback period vs radiators | 5-10 years | 2-5 years |
| London suitability | Best for extensions and ground floor | Best for bathroom/kitchen retrofits |
Wet (Hydronic) UFH
What Wet Underfloor Heating Installation Involves
Wet UFH is a full heating system in the floor. Here is what goes in, in order.
Pipes in screed or on insulation boards
Flexible polyethylene pipes are laid in loops on top of insulation. In new builds or extensions they go into a fresh screed pour. In retrofits, low-profile insulation boards raise the floor by 15-20mm.
Manifold fitted in cupboard or utility area
The manifold distributes water to each pipe loop, one loop per zone. A utility cupboard, understairs space or dedicated manifold box houses it -- plan the location before any floor work starts.
Connected to boiler via pump and actuators
A pump circulates hot water from the boiler through the manifold. Wired actuators open and close each zone valve in response to room thermostat calls.
Thermostats per room (wireless or wired)
Each zone has its own thermostat -- typically one per room. Wireless thermostats avoid cable runs through finished floors; wired stats are more reliable over time.
Floor sensors added to each thermostat
A cable sensor under the floor surface tells the thermostat the actual floor temperature, preventing overheating that could damage wooden floors or tiles.
28-day screed drying time before commissioning
Standard liquid screed takes 28 days to cure. During this time the UFH is run at low temperature for the final 7 days to accelerate drying. The floor finish cannot be laid until screed is fully dry.
Why most London wet UFH is done during extensions or renovations
The 28-day screed drying period -- plus the disruption of lifting all existing flooring -- makes wet UFH a major undertaking in an occupied home. It makes financial and practical sense as part of a wider building project where floors are already being opened up.
Electric UFH
What Electric Underfloor Heating Installation Involves
Electric UFH is the practical choice for London bathroom and kitchen retrofits -- less disruption, no boiler changes, installed in a day.
Heating mat or cable laid under floor finish
Mats are pre-spaced cables on a mesh carrier -- unroll and cut to fit the room. Loose cables allow more control over spacing and work better in irregular-shaped rooms.
Dedicated electrical circuit required (Part P)
Electric UFH is a notifiable electrical installation under Part P of the Building Regulations. It must be carried out or signed off by an NICEIC or NAPIT registered electrician.
Thermostat with floor sensor fitted
The thermostat controls heat output and the floor sensor cable runs under the mat between two heating cables. Most modern stats have programming, Wi-Fi control and holiday modes.
Single room typically installed in 4-6 hours
A bathroom (5-8m2) including mat, thermostat and electrical connection is a one-day job for an electrician and tiler working together. A kitchen adds a few hours.
No boiler connection required
Electric UFH is entirely independent of your heating system, which makes it ideal for adding to a bathroom that sits above a neighbour's flat, or to a property where boiler access is awkward.
Price Guide
Underfloor Heating Costs -- London 2026
All prices include VAT and London labour rates. Fixed quote provided before any work starts.
Prices vary with floor area, access difficulty and whether the boiler needs upgrading. Call for a fixed quote.
Boiler Compatibility
Does UFH Work With a Combi Boiler?
Yes -- but there are important sizing and efficiency considerations your engineer must check before installation.
UFH runs at lower temperatures
UFH operates at 35-45 degrees C flow temperature. Radiators need 65-75 degrees C. A combi boiler can supply both, but needs to modulate down significantly for UFH -- not all older combis do this efficiently.
Low-loss header or weather compensation helps
Adding a low-loss header decouples the UFH circuit from the boiler and allows the boiler to run at its optimal temperature. Weather compensation control (available on most modern combis) automatically adjusts flow temperature based on outside conditions -- improving seasonal efficiency by 10-15%.
Output capacity: combi vs system boiler
For 1-2 rooms of UFH in a 2-3 bed London home, a combi is typically fine. For whole-house UFH on a larger property, the total heat demand may exceed what a single combi can supply -- a system boiler with a separate hot water cylinder may be the better choice. Heat demand calculation required.
An engineer should calculate heat demand (in kW) for every room before specifying boiler output or manifold sizing. Undersizing causes rooms to never reach temperature; oversizing wastes money on plant.
Retrofit vs New Build
Choosing UFH Type by Project
London-Specific
London Considerations Before You Install
London's housing stock and water quality raise specific issues not covered in most generic UFH guides.
Victorian floor construction
Many London homes have suspended timber floors. These need rigid insulation boards under pipes to stop heat disappearing into the void beneath. The boards add 15-20mm to floor height -- check door clearances and transition strips to adjacent rooms before specifying.
Flat conversions -- freeholder permission
UFH installation affects the building structure and may create additional load or alter fire compartmentation. In London leasehold flats, check your lease and get written consent from the freeholder or managing agent before any floor work starts.
London hard water -- use inhibitor
London's water hardness (300mg/l+ calcium carbonate) will scale the inside of wet UFH pipes just as it does radiators. Fill the UFH circuit with a corrosion and scale inhibitor (same product as used in central heating systems). Test inhibitor concentration at each annual service.
Planning permission
Internal UFH installation does not require planning permission. If the project involves changing a boiler flue position on the outside of the building, check with your local authority -- in conservation areas, external alterations may need consent.
UFH Questions
Frequently Asked Questions
Planning Underfloor Heating in Your London Home?
Get a survey and quote from our heating engineers. We cover all London boroughs, carry out wet and electric UFH installation, and can assess whether your existing boiler needs upgrading to run the system efficiently.
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