Electric vs water underfloor heating: installation, efficiency and user reviews compared

If you’re looking for an efficient way of heating your home, with the luxury of a heated floor, underfloor heating is a great choice. 

There are two types of system: electric and water. 

There are several key differences between these systems, particularly in installation and running costs. That means that choosing the best system for you is very important. 

Read more: our guide to the pros and cons of underfloor heating

Electric vs wet underfloor heating: summary

The below table summaries key difference between electric and water underfloor heating. 

Read below for more information on these differences.

Logged in members can also see user feedback from over 130 Which? readers with underfloor heating. 

What is underfloor heating?

Electric underfloor heating

Electric underfloor heating consists of a long wire coiled underneath your floor, which is connected to the mains electricity supply. When the system is switched on, the wire gets hot; this then heats your floors and warms the air in the room.

Because electricity is more expensive than gas, electric underfloor heating is quite expensive to run, so it is typically only installed in a single room. 

Water underfloor heating 

In a water-based underfloor heating system, a series of pipes – typically connected to your boiler – circulates warm water under the floor to heat the space. 

This is similar to the way radiators work, which are also full of heated water. 

For a more sustainable option, you can connect your water heating to a solar water-heating system, or an air- or ground-source heat pump. 

Water underfloor heating is very cost-efficient, so it is generally installed in multiple rooms. For example, you might install it in the whole lower ground floor of your home during a renovation. 

Water vs electric heating: efficiency 

Water underfloor heating is more efficient than electric underfloor heating. 

It heats a room using water heated by a (typically gas) boiler, and that costs less than electricity. 

It's also usually cheaper than radiators as well, because it covers a much greater area, so the water in the system can be much cooler – as low as 35°C, compared with 55-65°C or higher for radiators. 

Electric systems are less efficient that water underfloor heating and radiators - but they can be cheaper than radiators for heating a single room if you can't zone your central heating. 

Running costs 

Based on estimates from underfloor heating manufacturers on how much hot water you'd need, we've calculated that the annual running costs for water underfloor heating for a 10m2 room can be as low as £45 over a year. 

This is significantly cheaper than electric underfloor heating, which in an equivalent sized room can cost as much as 36p per hour – or £33 a month if you used it for three hours a day.

Water vs electric heating: installation

In general, both electric and water underfloor heating will require you to remove your floor during installation. However, electric underfloor heating is much easier to install. 

Electric underfloor heating installation: 

• The process typically involves insulating the subfloor, then taping wires over the top and securing them a self-levelling compound.
• This can be completed by a competent DIYer. However, you will need a  qualified electrician to connect the system to the electricity supply and install the thermostat.
• Retrofitting (in which the system is fitted without taking up floorboards or digging up the floor of your home) is possible for some systems.

Water underfloor heating installation: 

• The process is more complex, and involves laying pipes into the subfloor, connecting the system to a manifold, and insulating the system. 
• It will require a professional. 
• Retrofitting is not normally possible. 

Installation costs

Every year, we purchase data from the Building Cost Information Service (BCIS), which provides us with cost estimates for different home improvement projects, such as installing underfloor heating, based on the price of labour and materials.

According to its data, water underfloor heating is around 25% more expensive to install per m2 than electric underfloor heating. 

See the detailed costs in our guide to underfloor heating costs and installation. 

Where can you install underfloor heating?

You can install both types of underfloor heating almost anywhere in your home. 

Electric underfloor heating is typically less bulky than water systems, which is useful for rooms with low ceilings if you're not keen on raising the level of your floor. 

Insulation for electric systems can be as little as 25mm thick and the wire itself 4-5mm thick, whereas water systems can be around 130mm thick – or even thicker if they are being retrofitted under an existing floor. 

In general, people install electric underfloor heating in single rooms, like the principle bathroom, and water underfloor heating in multiple rooms, like across an open-plan kitchen diner. 

Check our guide to underfloor heating costs and installation to find out the typical prices for different scenarios based BCIS estimates and reports from real users

User reviews of water and electric underfloor heating

It can be difficult to know whether the benefits of water underfloor heating are worth the investment until you've already made the decision. 

In May 2024, we asked 41 Which? members with water underfloor heating and 77 members with electric underfloor heating whether they thought it had been a worthwhile investment. 

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Users reported that each system had different advantages and disadvantages. Both sets of users recommended using a timer – but in different ways. 

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