The short answer
A wet underfloor heating system is generally cheaper to run than radiators, while an electric system usually costs more per unit of heat — so the running cost depends mainly on the system type and your heat source. Wet UFH runs at a low flow temperature, which suits a condensing boiler and works very efficiently with a heat pump; electric UFH converts electricity straight to heat at a higher unit price. Good insulation, smart controls and using the system as steady background warmth rather than short bursts all keep running costs down. These figures are general guidance, not a forecast of your bills.
Running cost is the question most people ask after the install price, and the honest answer is that it varies with the system, the heat source, your floor and how you use it. This guide explains what drives the day-to-day cost of underfloor heating, how wet and electric compare, and the practical steps that keep bills sensible. All figures are general illustrations, not a quote or a guarantee of savings, and underfloor heating should be fitted by a Gas Safe registered heating engineer (wet) or a NICEIC registered electrician (electric).
Running costs at a glance
- Cheaper to run Wet (water)
- More per unit of heat Electric (mat)
- Most efficient pairing Wet + heat pump
- Flow temperature Lower than radiators
- Biggest lever Insulation & heat source
- Best use pattern Steady background heat
Why wet underfloor heating is cheaper to run
A wet system warms a large surface — the whole floor — so it can heat a room to the same comfort level at a lower water temperature than radiators, which rely on a small, hot surface. That lower flow temperature lets a condensing boiler run more efficiently, and it is exactly the condition a heat pump needs to deliver several units of heat for each unit of electricity. The result is that a well-designed wet system, especially with a heat pump, is typically cheaper to run than radiators. See underfloor heating vs radiators for the comparison.
| System / heat source | Running cost | Why |
|---|---|---|
| Wet + heat pump | Lowest | Low flow temperature multiplies efficiency |
| Wet + gas boiler | Low | Large surface, efficient condensing operation |
| Electric mat | Higher per unit | Electricity costs more per unit than gas |
Why electric underfloor heating costs more per unit
Electric UFH turns electricity directly into heat at close to 100% conversion, which sounds efficient, but electricity costs more per unit than gas, so the cost of heat delivered is higher. That is why electric is best for small areas used occasionally — a bathroom warmed for an hour or two — rather than a whole house heated all day. For the cost comparison, see is underfloor heating expensive to run and wet vs electric cost.
What you can do to keep running costs down
- Insulate well — insulation under the system and a well-sealed room mean the heat goes up into the space, not down or out.
- Use a programmable or smart thermostat — UFH responds slowly, so steady scheduling suits it better than sharp on-off bursts. See warm-up times.
- Zone the system — heating only the rooms in use avoids paying to warm empty space.
- Choose a suitable floor finish — tile and stone conduct heat well; thick or insulating finishes slow it down. See underfloor heating under laminate and wood floors.
- Pair wet UFH with a heat pump where practical, for the lowest running cost.
Putting a figure on it
Because running cost depends on unit energy prices, your floor area, insulation, heat source and how long the system runs, a single national figure would be misleading. The reliable comparison is relative: wet UFH is generally cheaper to run than radiators and far cheaper than electric UFH for the same area, and the gap is widest with a heat pump. For a realistic estimate, ask your installer to model the running cost for your specific rooms and heat source. This is general information, not a forecast of your bills, and underfloor heating should be fitted by a Gas Safe registered heating engineer (wet) or a NICEIC registered electrician (electric).
Compare underfloor heating quotes
A well-designed system is what keeps running costs low. Use our service to compare quotes from a Gas Safe heating engineer or NICEIC electrician in your area.
Frequently asked questions
Is underfloor heating cheaper to run than radiators?
A well-designed wet underfloor heating system is generally cheaper to run than radiators, because it heats a large surface at a lower flow temperature, which lets a boiler run efficiently and suits a heat pump. Electric underfloor heating, by contrast, usually costs more per unit of heat. See UFH vs radiators.
Which underfloor heating is cheapest to run?
A wet system paired with a heat pump is typically the cheapest to run, because the low flow temperature lets the heat pump deliver several units of heat per unit of electricity. A wet system on a gas boiler is next; electric mats cost the most per unit of heat.
Should I leave underfloor heating on all day?
Underfloor heating responds slowly, so it usually suits steady background heating with a programmable or smart thermostat rather than sharp on-off bursts. Whether leaving it on low is cheaper than scheduling depends on your home and insulation — ask your installer to advise on controls for your setup.
Does the floor finish affect running costs?
Yes. Tile and stone conduct heat into the room well, while thick carpet or some insulating finishes slow it down, so the system has to work harder. Choosing a suitable, rated floor finish helps keep running costs sensible. See floors and UFH.
Sources & further reading
- Energy Saving Trust — underfloor heating running costs, efficiency and heat pumps
- Gas Safe Register — registered heating engineers for wet systems
- NICEIC — registered electricians for electric underfloor heating
- Manufacturer guidance — system design, controls and floor build-up
- GOV.UK / Building Regulations Approved Document L — efficiency standards
This is general information, not advice for your specific property and not a forecast of your bills. Running costs vary with energy prices, your home, insulation, heat source and use. Underfloor heating should be fitted by a Gas Safe registered heating engineer (wet) or a NICEIC registered electrician (electric). We are an independent information and introduction service, not an installer.