Water vs electric underfloor heating: which is right for your project?

Both systems warm the floor so the whole room heats evenly from below. The difference is what carries the heat. Water underfloor heating pumps warm water through plastic pipe loops connected to a manifold and your boiler or heat pump. Electric underfloor heating uses a thin heating cable, either fixed to a mesh mat or laid loose, wired to a floor-sensing thermostat.

This guide compares the two on install cost, running cost, floor height, heat source and floor finish, with worked examples using MaxHeatUFH kit prices (inc VAT, October 2026).

What is the difference between water and electric underfloor heating?

Water underfloor heating is part of your central heating, while electric underfloor heating is a stand-alone electrical heater for one area. That one fact drives most of the decision.

The Energy Saving Trust sums it up the same way: dry (electric) systems are generally cheaper to install than wet systems, but more expensive to run, so they suit quick warmth in small areas.

Which is cheaper to install?

Electric is cheaper to install in a single small room, because you need no pipework, manifold or pump. For a 4m² en-suite the kit difference is large:

As the area grows, the fixed parts of a wet system (manifold, pump pack, wiring centre) are shared across more square metres, so the cost per m² falls. Electric cost rises almost in line with area. A 20m² kitchen extension on castellated panels and screed needs about £850 of wet kit, or about £42/m², including a 2-port manifold and a Grundfos UPM3 Auto blending pump pack. Two 10m² electric mats plus a neoStat-e would be about £531, but they would then cost more to run every winter. Our underfloor heating cost guide breaks this down by system.

The Energy Saving Trust quotes typical installed costs of £50 to £85 per m² for electric and £85 to £110 per m² for wet systems, using figures from Checkatrade. Costs can be lower when you are already replacing the floor.

Which is cheaper to run?

Water underfloor heating is usually much cheaper to run, because gas and heat pump heat cost less per kWh than direct electric heat. Electric underfloor heating turns 1kWh of electricity into 1kWh of heat. A gas boiler and a heat pump do better than that per penny.

Fuel prices are the Ofgem price cap averages for 1 October to 31 December 2026, direct debit. The 90% boiler and SCOP 3 heat pump figures are example values; your own appliance will differ. The working is simple: divide the fuel price by the efficiency.

Worked example: a 4m² bathroom mat at 150W/m² draws 0.6kW. At 26.32p/kWh that is about 15.8p for each hour it runs at full power. Once the floor is warm the thermostat cycles the mat on and off, so real use is lower. Run it two hours each morning and evening at full power and you would pay about 63p a day. The same 0.6kW of heat from a 90% gas boiler would cost about 5.3p an hour.

So electric is fine where it runs for short periods in a small room. Across a whole ground floor heated all day, the gap adds up fast.

How much floor height does each system need?

Electric needs the least height: a mat or cable is 3 to 4mm thick and sits inside the tile adhesive bed. Water systems need room for the pipe and a board or screed to hold it.

• Electric mat or loose cable: 3 to 4mm in the adhesive, or a little more with an uncoupling membrane on timber or new screed.
• Wet, tile-direct routed XPS board: 18mm for 12mm pipe or 25mm for 16mm pipe. You tile straight onto it.
• Wet, castellated panel: 20mm panel, then screed or levelling compound over the pipe.
• Wet, joisted floor: 22mm grooved chipboard replaces the floor deck, with a 6mm top board over it.

In a renovation where every millimetre counts, electric or a low-profile wet board is often the only option. See our guide to underfloor heating floor systems for each build-up.

Which works with a heat pump?

Only water underfloor heating can be run by a heat pump. Air source heat pumps usually run at lower flow temperatures, around 45°C, and wet underfloor heating is commonly designed for flow temperatures of typically 35 to 45°C. Its large heated surface gives out enough heat at those low temperatures, which keeps the heat pump efficient.

If you are planning a heat pump now or later, fit a wet system. In England and Wales the Boiler Upgrade Scheme gives £7500 towards an air source or ground source heat pump. A heat pump usually runs the floor through a non-mixing pump set, because its water is already at floor temperature. A gas boiler runs hotter, so it needs a blending valve pump pack to bring the water down. Read more in underfloor heating with a heat pump.

Which floor finishes work with each system?

Both systems work under tiles, stone, LVT, laminate, engineered wood and carpet, but tile and stone give the best heat output. The Energy Saving Trust notes that stone and ceramic tiles transfer heat efficiently, thin vinyl and laminate can work, and carpet slows the heat. Keep the combined tog of carpet and underlay at 2.5 or lower.

Most electric mats are designed to go under tile and stone in an adhesive bed. Wet systems suit almost any finish because the screed or board spreads the heat. Whatever the system, floor surface temperature is limited under BS EN 1264 to 29°C in occupied areas, 33°C in bathrooms and 35°C in edge zones.

Can I fit it myself?

You can lay both systems yourself, but each has a part that needs a qualified person. For electric, the final connection must be made by a qualified electrician to BS 7671. Section 753 of BS 7671 requires floor heating to be protected by an RCD rated at 30mA or less. For wet, the manifold and pump pack must be connected to the boiler or heat pump by a competent heating engineer, and the loops pressure tested before the floor is covered.

Laying a mat in one bathroom is a common DIY job. A whole-house wet system is a bigger project, but many self-builders lay the pipe themselves and pay a heating engineer for the connection.

How do I choose between water and electric?

Answer these five questions in order. The first one that gives a clear answer usually decides it.

1. Do you have, or plan, a heat pump? If yes, choose water.
2. Is it a whole floor or more than one room? If yes, water is usually cheaper over the life of the system.
3. Is it one small room, such as a bathroom or en-suite? If yes, electric is simpler and cheaper to fit.
4. How much floor height do you have? Under about 15mm points to electric. 18mm or more opens up tile-direct wet boards.
5. Can you reach the heating pipework? If the room is far from the boiler or manifold, electric avoids long pipe runs.

Many homes use both: wet underfloor heating on the ground floor and an electric mat in an upstairs en-suite.

Products for this job

• Water underfloor heating: pipe, boards, manifolds and pump packs
• Electric underfloor heating: mats, loose cable and thermostats
• MaxHeatUFH Electric Underfloor Heating Mat 150W/m², 1 to 12m²
• Heatmiser neoStat-e electric floor thermostat
• Dualmix Stainless Steel Manifold, 2 to 12 port
• Single Room UFH Mixing Pump Pack for one wet room off a boiler
• MaxHeatPanel tile-direct routed XPS board
• Heat pump connection pump sets

Related guides: How much does underfloor heating cost in the UK?, Underfloor heating with a heat pump and Underfloor heating floor systems explained.

Frequently asked questions

Is electric underfloor heating expensive to run?

It costs more per kWh of heat than gas or a heat pump. At 26.32p/kWh, a 4m² mat at 150W/m² costs about 15.8p per hour at full power. In a small bathroom used for short periods that is manageable. Over large areas heated all day it gets expensive.

Can I run wet underfloor heating from a combi boiler?

Yes. A combi or system boiler can feed a UFH manifold through a blending valve pump pack, which mixes the boiler water down to floor temperature. For one room, a single room mixing pump pack can run straight off a radiator or boiler circuit without a manifold.

Which heats up faster, water or electric?

Electric under tiles usually warms up faster, because the cable sits just below the tile. Wet systems in screed take longer to warm, but they hold heat well and suit steady, all-day heating.

Is water underfloor heating worth it for one room?

Only if the heating pipes are close by, or the room is large, or you have a heat pump. For a single small bathroom, an electric mat is usually cheaper and simpler. For a 20m² kitchen extension, wet is usually the better long-term choice.

Can I have both water and electric underfloor heating in one house?

Yes, and many homes do. A common set-up is wet underfloor heating downstairs on the boiler or heat pump, with electric mats in upstairs bathrooms where running pipe is awkward.

Do I need an electrician for electric underfloor heating?

Yes, for the final connection. You can lay the mat and tile over it, but a qualified electrician must connect it to BS 7671, including 30mA RCD protection.

Does underfloor heating work with carpet?

Yes, but it slows the heat. Keep the total tog of carpet and underlay at 2.5 or lower. Tiles and stone give the best results with either system.

Sources: Energy Saving Trust: underfloor heating, Ofgem: energy price cap, 1 October to 31 December 2026, GOV.UK: Boiler Upgrade Scheme, nidirect: air source heat pumps, IET: BS 7671 Section 753 floor heating, Danfoss: EN 1264 floor surface temperatures