Question 1

Is underfloor heating cheaper to run than radiators?

Accepted Answer

Yes, typically 15-25% cheaper. Underfloor heating runs at 35-45°C flow temperature vs 60-75°C for radiators, making it ideal for heat pumps (which are most efficient at low temperatures). The larger surface area means lower temperature water heats the room effectively. With a gas boiler, the savings are smaller (10-15%).

Question 2

Can you retrofit underfloor heating?

Accepted Answer

Yes, but it is more disruptive and expensive than in new builds. Options include: overlay systems (18-25mm added height, laid on existing floor), or full screed systems (requiring floor removal, 65-75mm depth). Overlay systems cost £60-90/m² installed. Electric UFH mats are the easiest retrofit option at £30-50/m².

Question 3

How long does underfloor heating take to warm up?

Accepted Answer

Wet (water) underfloor heating in a screed floor takes 2-4 hours to reach temperature from cold. Once warm, it maintains temperature with minimal energy. Radiators reach temperature in 15-30 minutes. UFH needs a thermostat with setback scheduling rather than on/off control. Electric UFH mats heat up in 20-30 minutes.

Question 4

Can you have both radiators and underfloor heating?

Accepted Answer

Yes, this is common. Many UK homes use underfloor heating on the ground floor (kitchen, living room, hallway) and radiators upstairs (bedrooms, bathroom). A mixing valve reduces the flow temperature to the UFH zones. This combination gives the benefits of both systems where they matter most.

Question 5

Does underfloor heating work with all floor coverings?

Accepted Answer

Most floor coverings work, but some are better than others. Best: porcelain/ceramic tiles, stone, polished concrete (high conductivity). Good: engineered wood, LVT vinyl. Acceptable: laminate (check manufacturer). Poor: thick carpet and underlay (insulates the heat). Keep carpet tog value below 1.5 for UFH.

Property	Radiators	Wet UFH (in screed)	Electric UFH
Install cost per m²	£30-60	£50-80 (new build)	£30-50
Retrofit cost per m²	£30-60	£80-120 (overlay)	£40-60
Flow temperature	60-75°C	35-45°C	N/A (electric)
Warm-up time	15-30 minutes	2-4 hours (screed)	20-30 minutes
Running cost	Higher (high flow temp)	15-25% less (low flow temp)	Highest (electricity rate)
Heat pump compatible	Yes (if oversized)	Ideal (low temp)	N/A
Floor height impact	None	65-75mm (screed), 18-25mm (overlay)	3-6mm
Maintenance	Bleed, balance, replace	Very low (pipes last 50+ years)	None (no moving parts)
Floor covering restriction	None	Avoid thick carpet	Avoid thick carpet

Cost Element	Radiators	Wet UFH (new build)
Materials	£600-1,200 (6 radiators)	£1,200-2,000 (pipe, manifold, insulation)
Installation labour	£600-1,000	£1,500-2,500
Controls (thermostats, actuators)	£100-200	£300-600
Total installed	£1,300-2,400	£3,000-5,100
Annual running cost saving	Baseline	£100-200/year less

Radiators vs Underfloor Heating — UK Guide

Side-by-Side Comparison

UK Cost Comparison (2026 Prices)

When to Choose Each

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