Can You Lay a Rug Over Underfloor Heating?
So you’ve installed an underfloor heating system, or maybe you’re considering installing one. It’s a great way to make a room cosy, but what if you wanted to make a room even cosier or homely with a rug?
While it’s perfectly fine to have underfloor heating for carpeted flooring, with rugs, it’s a little different. While most carpets allow for effective heat transfer between the pipes and the floor above, some rugs can restrict heat transfer and the efficient heating distribution underfloor heating is known for.
But a rug is not automatically a deal breaker. Here’s how to pick a rug that will pair well with your underfloor heating for wooden flooring.
How to Choose a Rug for Heated Floors
The Material Matters
You want a rug fibre that is good at facilitating heat transfer. Natural fibre rugs made of cotton and silk are generally safe with an underfloor heating system. Synthetic fibres like nylon and polypropylene can transfer heat, but have lower melting points and are at risk of melting when heated beyond their limits.
Wool rugs are more insulating, and therefore shouldn’t be too thick if you want a rug in this material. More on this in the next section. Be aware of the backing material too. Burlap and jute are good at transferring heat, but rubber, synthetic rubber, and felt are not. If you want efficient heating, you have to consider both sides of the rug.
Silk and wool can withstand up to 40°C. Past that, they start to shrink. Cotton meanwhile, can withstand much higher temperatures. Rug shrinkage and fibre damage are less likely to occur with a well-designed system, as the boiler flow temperature of a heated floor system will typically run around 40°C. This temperature decreases as it passes through your house and transfers to the floor covering. But if a hot spot occurs due to being obstructed by a thick, insulating rug, the floor may reach temperatures above this.
How Thick Can a Carpet be With Underfloor Heating?
A thickness of less than 25mm is generally safe for underfloor heating with carpeted flooring and rugs. The thicker the rug, the more likely it is to insulate and affect heat transfer. Too thick, and this can create a hot spot and risk the fabric warping or shrinking.
Thick woolly rugs or shag rugs are the kinds of rugs that are at risk of becoming hot when covering underfloor heating for wooden flooring.
Other Factors to Consider
Always check the rug’s tog rating, which indicates how effective it is at retaining heat. Anything higher than 2.5 is too insulating and could cause hotspots or reduce the effectiveness of your heating. You should also avoid very large rugs, even if they’re of a suitable material or thickness, because these lower efficient heating transfer between the pipes and the floor.
Are Antique Rugs Safe with Underfloor Heating?
You should not lay unique rugs on heated floors. The majority of these rugs are frail due to their old age and should be placed away from sources of heat or sunlight.
Are Persian Rugs Safe with Underfloor Heating?
Persian rugs made of cotton, wool, or silk can be used with underfloor heating. Wool is the most common material used in authentic rugs, but it is usually woven quite thin. Remember to check the tog rating if you need clarification.
Will Underfloor Heating Work With Carpet?
Carpets will work with heated floors if it has a tog rating of 2.5 or below. Higher tog ratings will affect the transfer of heat, making the system less efficient. A carpet can be thick if it has a tog rating less than 2.5. Generally, this should not be thicker than 25mm.
What About Braided or Hand-Woven Rugs Without a Tog Rating?
As long as these rugs are thin and made with natural fibres, they should be safe to put over a heated floor. Handmade rug makers are likely to use synthetic yarns because of their low cost, and these can have lower heat resistance than mass-produced synthetic rugs. Don’t be afraid to ask about the materials and their care instructions from the artist.
Contact the Underfloor Heating Team
Haven’t started on your underfloor heating journey? Over the years, EasyFlow’s teams across the UK have worked with many homeowners and construction companiesto bring underfloor heating and our full flooring solution to many different properties.
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