Wet Underfloor Heating vs Electric Mats: Which Is Right for Your Cornwall Home?

The Two Types of Underfloor Heating

Underfloor heating (UFH) comes in two fundamentally different forms. Wet (hydronic) underfloor heating circulates warm water through a network of pipes embedded in or laid over the floor, connected to a heat source — your boiler or heat pump. Electric mat or cable heating runs electrical resistance cables under the floor finish, converting electricity directly to heat.

Both warm your floor from below and create a comfortable, even heat. The installation costs, running costs, and appropriate use cases are dramatically different.

Installation Costs Compared

For a typical Cornwall kitchen-diner (25m²):

	Wet UFH	Electric mat
Materials	£800–£1,400	£150–£300
Installation labour	£600–£1,200	£100–£200 (electrician only)
Screed/floor finish	£300–£600 (if screed required)	£0 (under existing tiles/LVT)
Total for 25m²	£1,700–£3,200	£250–£500

Electric is clearly cheaper to install. But this upfront comparison hides the long-term story.

Running Costs: The Critical Difference

Electric resistance heating converts 1 kWh of electricity to 1 kWh of heat — 100% efficiency. At the standard Cornwall electricity tariff of roughly 24p/kWh, heating a 25m² room electrically for 8 hours a day costs approximately £1.50–£2.20 per day in winter.

Wet UFH connected to a heat pump converts that same 1 kWh of electricity to 3.0–3.8 kWh of heat (SCOP 3.0–3.8). The same room heating costs £0.40–£0.80 per day. Over a 5-month heating season, the saving is £185–£420 per room.

Wet UFH connected to a gas boiler at 24p/kWh equivalent fuel cost runs at similar or slightly higher cost than electric mats, because gas boilers work least efficiently at the low flow temperatures UFH requires. Wet UFH genuinely shines when paired with a heat pump.

Heat Pump Compatibility

Heat pumps produce water at 35–45°C rather than the 65–70°C of a boiler. Traditional radiators sized for boiler temperatures struggle to emit enough heat at these lower temperatures. Wet UFH, by contrast, works best at 30–40°C — it has a large surface area and low flow temperature requirements that match heat pumps perfectly.

If you're considering a heat pump installation, wet UFH on the ground floor dramatically improves system efficiency and reduces the need for oversized or replacement radiators upstairs. Most of our Cornwall self-build installations use UFH ground floor and large rads upstairs — the best of both worlds.

Electric mats are incompatible with heat pumps in any meaningful sense — the heat pump heats water, not cables. Running a heat pump to generate hot water and then also running electric mats for spot heating defeats the efficiency benefit of the heat pump entirely.

When Electric Mats Make Sense

Electric mat heating is the right answer in specific situations:

• Bathroom tile warming — a small electric mat under bathroom tiles (4–8m²) to take the chill off in the morning, not for room heating. Cost-effective at this scale.
• En-suite or small WC — where wet system installation would require significant disruption and the area is too small to justify it.
• Rental property or landlord installation — lowest upfront cost, and the running cost disadvantage falls to the tenant (though this is ethically questionable).
• Properties with no heat pump and no plans for one — where you just want warm floors in one room and have no gas boiler either. Off-grid properties with solar and battery can offset the electricity cost.

When Wet UFH Makes Sense

Wet underfloor heating makes sense when:

• You're installing or planning to install a heat pump
• You're doing a ground-floor renovation where screed is going down anyway
• You're building a new extension with concrete slab
• You're in a self-build or new build — it should be designed in from the start
• You want to use the heat pump in both heating and cooling modes (wet UFH can carry cooled water too)

The Verdict for Cornwall Homes

For Cornwall homeowners with a heat pump or planning one, wet UFH pays back within 3–5 years compared to electric mats purely through running cost savings. For bathroom tile warming only, electric wins. For anything in between — consult your installer about your specific property's heat requirements, floor build-up constraints, and heating system.

We install both wet UFH and can advise on electric mat suitability. Contact us for a free consultation, or see our full underfloor heating page for more details on the wet systems we install.