The choice between radiators and underfloor heating is one of the most consequential decisions in a renovation or new build. Both systems can heat a home effectively, but they do so in different ways, suit different situations, and have very different upfront and running costs. The right answer depends on your heat source, your floor construction, your budget, and how you use your home.
This guide gives you a straight comparison so you can make an informed decision.
How Each System Works
Radiators emit heat primarily by convection — they heat the air around them, which rises and circulates through the room. A standard radiator operates with flow temperatures of 60–80 °C in a conventional boiler system, though low-temperature radiators can work at 45–55 °C.
Wet underfloor heating (UFH) circulates water through loops of pipe embedded in the floor screed or fixed to floor insulation boards. The entire floor surface becomes the emitter, typically reaching 25–29 °C. Because heat is distributed over a large area at low temperature, UFH is highly compatible with heat pumps and condensing boilers operating in condensing mode.
Electric underfloor heating (mat or cable) is a separate product — useful for individual rooms but generally too expensive to run as a whole-house heating solution and not covered in detail here.
Side-by-Side Comparison
| Factor | Radiators | Wet UFH |
|---|---|---|
| Installation cost (per room) | £150–£400 | £800–£2,500 |
| Installation cost (£/m²) | N/A | £60–£120/m² |
| Flow temperature | 60–80 °C (conventional); 45–55 °C (low-temp) | 30–50 °C |
| Heat pump compatibility | Moderate (needs low-temp rads) | Excellent |
| Response time | 15–30 minutes | 1–4 hours |
| Retrofit suitability | Excellent | Difficult (floor build-up) |
| Running costs (with gas boiler) | Broadly comparable | Slightly lower |
| Running costs (with heat pump) | Higher (needs larger rads) | Lower (optimal match) |
| Floor space freed | No | Yes (no wall space used) |
| Floor covering compatibility | Any | Tile/stone best; carpet/thick wood limits performance |
| Lifespan | 15–25 years (radiators) | 50+ years (pipes in screed) |
| Comfort feel | Warm localised zones | Even, gentle warmth |
Cost in Detail
Radiator Installation
A new radiator in an existing system — replacing like-for-like — typically costs £150–£350 supply and fit per unit, depending on radiator size and access. A full new radiator system for a three-bedroom house (8–10 radiators plus pipework) runs £3,500–£7,000 fitted by a Gas Safe registered plumber/heating engineer.
Upgrading to low-temperature radiators (larger panel surface area for the same output at lower temperatures) costs £200–£600 per radiator for quality units.
Underfloor Heating Installation
Wet UFH costs depend heavily on floor construction:
| UFH System Type | Cost per m² (supply + install) |
|---|---|
| Screed system (new build or full renovation) | £60–£90/m² |
| Low-profile overlay system (retrofit, 15–20 mm build-up) | £80–£120/m² |
| Staple-up below suspended timber floor | £55–£85/m² |
For a 100 m² ground floor: expect £6,000–£12,000 for the floor circuits plus £1,500–£3,500 for manifold, pump set, controls, and commissioning.
Electric underfloor heating (mat): £30–£60/m² supply and fit, but running costs are three to four times higher than wet systems.
Efficiency and Running Costs
With a gas condensing boiler, both systems can be broadly similar in running cost — the key variable is the flow temperature. Radiators at high flow temperatures cause a boiler to run in non-condensing mode (lower efficiency). UFH’s low flow temperatures keep most modern condensing boilers in condensing mode consistently, reducing gas consumption by roughly 10–15 %.
The real efficiency advantage of UFH emerges with a heat pump. Heat pumps become significantly more efficient (higher COP) as their output temperature drops. A heat pump delivering water at 45 °C to UFH might achieve a COP of 3.5–4.0; the same heat pump delivering 55 °C to radiators might achieve only 2.5–3.0. Over a heating season, this difference translates to meaningfully lower electricity bills — potentially £200–£600/year for a typical home, depending on system design and usage.
Retrofit Considerations
Radiators are the default retrofit choice. Adding a radiator to an existing system requires extending pipework — usually straightforward and low-disruption. Replacing old radiators is typically a one-day job per room.
UFH retrofit is feasible but rarely simple. The main challenges:
- Floor build-up: Screed systems add 70–100 mm to the floor height, which affects door clearances, skirting boards, and connections to adjacent rooms. Low-profile overlay systems (15–20 mm) are possible but may require wider pipe spacing and higher flow temperatures.
- Suspended timber floors: Pipes can be clipped between joists from below (staple-up method) or fixed to insulation boards in the joist bays. Accessible underfloor space is needed; this limits feasibility in many older UK houses.
- Heat emitter size: A room designed around radiators may already have adequate heat loss calculations for UFH — or may not. A heat loss calculation per room (following BS EN 12831) should confirm suitability before committing.
Which Floor Coverings Work?
UFH performance is affected by the thermal resistance of the floor covering. The total tog value of floor covering plus underlay should be below 1.5 tog for effective heat transfer.
| Floor Covering | Suitability for UFH |
|---|---|
| Porcelain or ceramic tile | Excellent |
| Natural stone | Excellent |
| Engineered wood (≤18 mm, low tog) | Good |
| Luxury vinyl tile (LVT) | Good |
| Laminate (UFH-rated) | Moderate |
| Solid hardwood | Poor (risk of shrinkage/warping) |
| Carpet with underlay | Poor (combined tog too high) |
If you plan carpet throughout, radiators are the simpler and more effective choice.
When to Choose Radiators
- You are retrofitting heating into an existing house without major floor works
- Your floor coverings include carpet or thick hardwood
- You need fast response heating (weekend cottage, intermittently occupied home)
- Your budget does not stretch to UFH installation
- Your boiler is modern and you want low disruption
When to Choose Underfloor Heating
- You are doing a full ground-floor renovation with new screed or overlay floors
- You are installing a heat pump (UFH is the optimal emitter pairing)
- You want to maximise floor space and eliminate radiator aesthetic
- Your floor finishes are tile, stone, or low-tog engineered wood
- You prioritise comfort in bathrooms or open-plan living spaces
Can You Mix Both?
Yes — and many architects and heating engineers recommend it. A common approach for two-storey homes: UFH throughout the ground floor (easier to install in screed during construction) and radiators on the first floor (easier and cheaper than running manifold circuits upstairs). Both circuits can be served from the same boiler or heat pump via the manifold and radiator circuits in parallel, with appropriate controls for each.
The heating design should be done by a qualified engineer who will calculate room-by-room heat loss, specify emitter sizes, and design the hydraulic circuit to balance both systems efficiently.
