Can you put a rug over underfloor heating? You can, but experts warn it may need more consideration than you think

Underfloor heating is a popular option with those extending, renovating or even building their homes from scratch. Whether you've installed the underfloor heating yourself, or have bought a home that already has it installed, it's important you understand the factors that can impact how well it works.

While there are plenty of floorcoverings that work really well with underfloor heating, you might be tempted to add a rug to change up the room's decor scheme or add a touch of softness underfoot. But is it a good idea or should you avoid it? I asked the experts to see what they recommend.

Can you put a rug over underfloor heating?

You can absolutely put a rug over underfloor heating, but if you don't want to negatively impact how well your UFH works, you'll need to choose wisely.

'Underfloor heating can be an effective way to warm a home, but it works best when heat can pass through the floor surface and into the room,' says Scott Byrom, home energy expert at The Energy Shop. 'Adding a rug introduces an insulating layer, so choosing the right one matters. Before putting a rug over underfloor heating, check that it is compatible with both your heating system and your flooring.'

In a similar way that you can have underfloor heating with carpet, if you choose an incompatible type of rug, you run the risk of leaving your space cold and unevenly heated.

How can laying a rug impact your underfloor heating?

Before you can choose the right kind of rug to sit over underfloor heating, it's worth understanding the impact a rug can have on how well it works.

'A rug adds resistance to heat passing from the floor into the room, says Scott. 'If it is too insulating, the room may take longer to warm up or struggle to reach the temperature you’ve set. Depending on the system and its controls, this could also increase running costs.'

Adding a rug may also cause damage to your chosen floorcovering below. 'There's also the possibility of heat building up beneath the rug, especially if it's thick or has a heavy insulating backing,' adds James Higgins, flooring expert at Online Carpets. 'Depending on the type of underfloor heating and the flooring installed above it, this could cause temperatures beneath the rug to rise beyond the levels recommended by the manufacturer.

'With flooring such as laminate, LVT and engineered wood - where maximum surface temperatures can apply - it's always worth checking the guidance for both your flooring and heating system before introducing a rug.'

Are some rug materials better than others?

So if you do want to lay a rug over your underfloor heating, should you focus your search on particular materials? That, and more, says James. 'I'd recommend looking for lightweight, low-pile designs that allow warmth to pass through more easily,' he says. 'Flatweave rugs and thinner woven styles are good options, as they create less of an insulating barrier than thick, deep-pile rugs.'

'Natural fibres are not automatically suitable,' adds Scott. 'Wool, for example, is naturally insulating, so a thick wool rug can still restrict heat transfer. Equally, you shouldn’t assume that every synthetic rug is unsuitable.

'Check the backing and any separate underlay, too. Some heating manufacturers advise against rubber-backed rugs, while thick felt underlays can add substantial insulation. Choose products specifically approved for your heating system and floor finish.'

Is there a recommended rug thickness for underfloor heating?

While thinner rugs tend to be more suitable, there's not necessarily a recommended thickness you should be looking for.

'There's no single thickness that I'd recommend for every rug and underfloor heating system, because two rugs of the same thickness can behave differently depending on the fibres, density and backing,' explains James.

'What matters most is the rug's thermal resistance, which tells you how much it restricts the transfer of heat. With carpet and underlay, for example, we often look at tog ratings to understand how easily heat can pass through the flooring. The same principle applies to rugs, although not every rug manufacturer provides this information.'

If you have plans for a thick, luxurious rug, however, you might want to rethink your plans. 'Generally, thinner rugs or those with open weaves tend to allow heat to pass through more effectively than heavier, densely layered options,' adds Sam Jump, Head of Business Development at Wunda Group. 'The key factor is the overall insulating properties. Be careful to check choices of underlay as some are better than others when it comes to tog value and heat resistance.'

When it comes to tog ratings, it's best to check the manufacturer's instructions for specific guidance. 'The permitted combined TOG rating depends on the heating system and the layers above it,' says Scott. 'Some systems allow up to 2.5 TOG, while others specify a lower limit, such as 1.5. Follow your manufacturer’s guidance and include any backing, underlay or other relevant layers in the calculation.

'If the rug’s TOG rating isn’t listed, ask the supplier for confirmation of its suitability rather than relying on pile height alone.'