Underfloor Heating in London Homes: Wet vs Dry Systems, Costs, and What to Expect
Underfloor heating (UFH) has moved from a luxury feature to a mainstream expectation in new extensions and ground floor refurbishments across London. When done right, it delivers comfortable, efficient warmth with no visible radiators taking up wall space. This guide covers the two main systems, when each makes sense, and what installation costs in London in 2026.
Wet (Hydronic) Underfloor Heating
A network of water-carrying pipes embedded in or fixed on top of the floor structure, connected to the boiler or heat pump.
How it works: Warm water (typically at 35–55°C, much lower than radiator systems) circulates through pipes laid in loops across the floor. The floor surface itself becomes the radiator, radiating heat upward uniformly.
Advantages:
- Lower running costs than electric systems for whole-floor heating
- Compatible with heat pumps (which operate efficiently at low flow temperatures)
- Provides even heat distribution with no cold spots
- Works with all floor finishes (tile, stone, engineered wood, vinyl — with appropriate screed)
Disadvantages:
- Higher installation cost and complexity than electric
- Requires either a screeded floor build-up (adding height) or a low-profile overlay system
- Slower response time than electric — needs to be scheduled, not just turned on
- Requires manifold installation and zone controls
Best applications: New extensions, kitchen refurbishments, open-plan ground floors, new-build rooms where floor height can be adjusted at design stage.
Typical installation cost (London, 2026):
- Screed-based wet UFH (new extension, per m²): £65–£100/m²
- Low-profile overlay wet UFH (retrofit, per m²): £85–£130/m²
- Manifold, controls, and commissioning (per zone): £600–£1,200
Electric (Dry) Underfloor Heating
Thin heating mats or cables installed directly beneath the floor finish.
How it works: Electrical resistance cables generate heat directly. The floor finish heats up quickly because there is minimal thermal mass between the element and the surface.
Advantages:
- Low installation cost
- Fast response — can be turned on and off like an electric heater
- Very thin profile — suits retrofits where floor height cannot be raised
- Simple installation — no plumbing required
Disadvantages:
- Higher running costs than wet systems for large areas
- Not recommended as a primary heat source for large rooms (expensive to run)
- Most economical for bathrooms, en-suites, and smaller spaces
Best applications: Bathrooms, en-suites, utility rooms, smaller kitchen areas where wet UFH is not cost-effective.
Typical installation cost (London, 2026):
- Electric UFH mat supply and installation: £40–£70/m²
- Thermostat: £80–£200 per zone
Floor Finish Compatibility
Not all floor finishes work equally well with UFH:
| Floor Finish | Wet UFH | Electric UFH | Notes |
|---|---|---|---|
| Porcelain/ceramic tile | ✅ Excellent | ✅ Excellent | Best thermal conductor |
| Stone (limestone, marble) | ✅ Excellent | ✅ Good | Excellent conductor |
| Engineered wood | ✅ Good | ✅ Good | Max surface temp 27°C — choose approved species |
| Solid wood | ⚠️ Caution | ⚠️ Caution | Risk of movement — check manufacturer approval |
| Vinyl/LVT | ✅ Good | ✅ Good | Use low-temperature-rated products |
| Carpet | ❌ Poor | ❌ Poor | Insulating — significantly reduces efficiency |
Tile and stone are the ideal pairing for UFH in London extensions and bathrooms.
Building Regulations and Heat Loss
For wet UFH to work efficiently, the floor, walls, roof, and windows of the heated space must meet minimum insulation standards. Poorly insulated spaces lose heat faster than UFH can comfortably provide — and running costs climb accordingly. Part L of the Building Regulations sets minimum U-values, and heat loss calculations should be carried out before UFH is specified to confirm the system will perform as expected.
Integration with Heat Pumps
A significant benefit of wet UFH is its compatibility with air source heat pumps (ASHPs). ASHPs are most efficient when delivering water at low temperatures (35–45°C) — exactly the flow temperatures wet UFH requires. Radiator systems need higher temperatures (60–70°C) that reduce heat pump efficiency. If you are planning a heat pump installation alongside a refurbishment, designing the UFH system and the heat pump together from the outset produces the most efficient result.
RCB Design & Build
RCB installs wet and electric underfloor heating systems as part of ground floor refurbishments and extensions across London. We coordinate screed specification, manifold location, zone controls, and floor finish compatibility. Contact us to discuss UFH for your project.