Underfloor Heating: Costs, Types & Is It Worth It?

Underfloor heating promises a warmer, clutter-free home without radiators along the walls, but the decision between wet and electric systems, and whether UFH is genuinely cost-effective, depends heavily on how you use the space, what heat source you have, and what the floor construction is.

For a typical UK kitchen-diner of 25 m², electric mat UFH costs roughly £1,250–£3,750 installed (25 m² at £50–£150/m²), while a wet system laid in a new screed and serving the same zone from an existing combi boiler costs roughly £3,100–£7,800 once the manifold and boiler connection are included. Neither figure tells the whole story without running costs, so this guide covers both.

Wet vs Electric Underfloor Heating

The most important decision is which system type is appropriate for your situation.

Electric underfloor heating

Electric UFH uses resistance heating cables or pre-made mats laid beneath the floor finish. Installation is relatively simple, there is no pipework, no manifold, and no need to connect to the boiler circuit. A qualified electrician connects the mat to its thermostat and the consumer unit; whether the work is notifiable under Part P depends on the circuit and where it is (see Building Regulations below).

Best suited to:

• Bathrooms, ensuites, and small tiled areas where you want a comfort heat boost
• Retrofits where disruption to screed or joists must be minimised
• All-electric homes without a wet heating system, where there is no boiler circuit to extend

Limitations:

• High running cost at the price cap electricity rate of 26.32p/kWh for 1 October to 31 December 2026¹
• Not efficient as the sole heat source for large open-plan areas
• Only realistic as primary heat in well-insulated rooms

Wet (hydronic) underfloor heating

Wet UFH circulates warm water, typically at around 35°C rather than the 55–65°C or more used by radiators, through plastic pipes laid in a screed floor or fixed to a timber subfloor.² A manifold distributes flow between zones, each with its own thermostat.

Best suited to:

• Whole-house systems in new builds or major renovations where floors are open
• Ground-floor extensions where a new screed is being poured
• Properties with heat pumps: a heat pump works more efficiently the lower the water temperature it has to supply, and wet UFH runs at the low flow temperatures (around 35–45°C) that suit it³

Limitations:

• Higher installation cost and significant disruption: adding UFH to existing timber floors means either a liquid screed overlay (40–65 mm added floor level) or cutting into joists
• Slower response times (often several hours from cold) make it better suited to systems left running continuously at a setback temperature rather than switched on-demand
• Needs occasional manifold maintenance: balancing, checking actuators and bleeding circuits

Installation Costs

Electric UFH installation costs

Thermostats with Wi-Fi scheduling typically add roughly £80–£180 per zone, and the scheduling cuts running hours.

Wet UFH installation costs

Wet system pricing varies considerably based on floor construction and whether a screed is being poured regardless (e.g. in an extension).

Where wet UFH is added to an existing property’s timber floor using aluminium diffuser plates rather than a screed, the floor level rises by only 18–22 mm, manageable in most cases. On an extension the screed is normally part of the build cost anyway, so the per-m² figures above pay for the UFH itself (pipe, insulation, fixings and labour) rather than for extra floor construction.

Running Costs: Wet vs Electric

This is where the comparison becomes critical.

Electric UFH mats are usually rated at 140–200 W/m² at full load.⁴ That rating is not what the room uses: once the room is warm the thermostat cycles the mat, so for a fair comparison the examples below give every system the same average heat demand of 70 W/m². At the price cap electricity rate of 26.32p/kWh from 1 October 2026, a 20 m² bathroom-to-open-plan area running 6 hours/day would cost:¹

• 20 m² × 0.07 kW/m² × 6 h = 8.4 kWh/day × £0.2632 = £2.21/day, or roughly £66/month in peak winter

Every unit of heat from an electric mat is a unit of electricity bought at the full rate, about three times the cost of the same heat from a 90% efficient gas boiler at these capped prices, so electric UFH as primary whole-house heating quickly becomes expensive.

Wet UFH with a gas combi boiler at 90% efficiency, heating to 45°C flow temperature, has to deliver the same roughly 60–80 W/m² of heat (70 W/m² in the example). At the price cap gas rate of 7.97p/kWh:¹

• 20 m² × 0.07 kW/m² × 6 h ÷ 0.90 efficiency = 9.3 kWh/day × £0.0797 = £0.74/day

Wet UFH with an air source heat pump (seasonal COP of 3.5, which assumes the low flow temperatures UFH allows) brings electricity consumption down to roughly 0.02 kW/m² for the same heat output (0.07 kW/m² ÷ 3.5), making it the cheapest option per unit of heat delivered, though only by about 15% against gas at these capped prices. Installing the heat pump itself typically costs around £12,000 (before grant; Boiler Upgrade Scheme grant: £7,500).⁵ For the same 20 m² area:

• 20 m² × 0.07 kW/m² × 6 h ÷ 3.5 = 2.4 kWh/day × £0.2632 = £0.63/day

That result depends on a good low-temperature design. At the 2.9 seasonal average that the government-funded Electrification of Heat trial measured across its air source heat pumps, the same area would cost about £0.76 a day, slightly more than gas.⁶

Best Use Cases

UFH is unambiguously the right choice when:

• You are pouring a new screed in an extension, the pipe adds minimal cost and the system is virtually free at that point
• You are installing an air source heat pump and want to maximise efficiency, wet UFH at 35–45°C is the ideal pairing, and the Boiler Upgrade Scheme (£7,500 grant as of 2026) can offset heat pump costs⁷⁸
• You want to heat a tiled floor in a bathroom or kitchen as a comfort supplement, electric mats are cost-effective and simple here

UFH is harder to justify when:

• You are retrofitting to a finished house with existing radiators and no other reason to open floors, unless it is part of a broader renovation
• You have poor insulation (uninsulated walls, or loft insulation well short of the 270 mm usually recommended), sort the building fabric first⁹
• The property is a rental let where you want quick, on-demand heat, UFH’s slow thermal mass works against intermittent occupancy

Building Regulations and Planning

Electric UFH is notifiable under Part P of Building Regulations if it involves a new circuit from the consumer unit, or an alteration to an existing circuit inside the special location, which runs from finished floor level to 2.25 m and 0.6 m out from the edge of the bath or shower tray, or 1.2 m from the shower head where there is no tray.¹⁰ It is the zone that is caught, not the whole room. Use a registered competent person (NICEIC, NAPIT or another scheme) to self-certify, or submit a building notice to Building Control.¹¹ The building notice fee is set by each council and varies widely: Chichester, for example, charges £841 plus VAT where the installer cannot certify the electrical work.¹²

Adding wet UFH to an existing boiler system still has to meet Part L, but adding an output or control device to an existing heating system is often exempt from notification to Building Control.¹³ If you are also installing a new heat pump, the installer must be MCS certified for you to claim the Boiler Upgrade Scheme grant.¹⁴ The heat pump installation itself must comply with Part L (energy efficiency) of Building Regulations.

Underfloor heating does not need planning permission: works that affect only the interior of a building are not development.¹⁵ In a listed building, listed building consent may still be needed for significant internal works.¹⁶

Timescales

The screed curing period is the critical path in any wet UFH project, you cannot lay tiles, LVT, or engineered wood until the screed moisture content falls below 75% RH (checked with a calibrated hygrometer).¹⁷ As a rule of thumb, a calcium sulfate (anhydrite) screed dries at about 1 mm a day up to 40 mm thick in good conditions (20°C air and no more than 65% relative humidity), and more slowly beyond that.¹⁸

Is It Worth It?

For a new extension with a new screed, wet UFH is almost always worth adding, the marginal cost is low and it pairs perfectly with a future heat pump. For a bathroom upgrade, electric mats deliver comfort for a reasonable upfront cost. For whole-house retrofit in an older property with joists and radiators, the disruption cost typically means a long payback period, often well over a decade.

If you are planning a heat pump installation under the Boiler Upgrade Scheme, designing the ground floor around wet UFH from the outset is strongly recommended, it is the single most effective way to keep the heat pump’s flow temperature, and therefore its running costs, as low as possible.