Underfloor heating is becoming an increasingly popular method of keeping homes nice and toasty, especially as it frees up wall space otherwise taken up by radiators and provides an even spread of heat throughout the room. Yet, many people are worried over the safety of placing intricate carpets or designer rugs on heated floors. Luckily, it’s still possible to decorate your floor space despite the wiring or piping hiding beneath your flooring but there are a few factors you will need to consider before choosing your contemporary rugs or carpets to be placed onto your heated floor.
Electric underfloor heating vs. water underfloor heating
Before thinking of a suitable rug, you must choose between the two types of underfloor heating. Electric underfloor heating (image above, right) consists of flexible pads/tiles containing electrical cables that provide the heat source which are installed underneath the flooring.
The water-based heating (image above, left) works by connecting a web of hot water pipes to the boiler bringing ambient heat into the room works well with carpets and rugs, the system is bulky so your floor would likely need to be raised slightly during installation. Water based underfloor heating is more expensive to install but the heating bills over the years should be much less than electrical underfloor heating so is a good long term investment.
How rugs can work on heated floors: tufted vs. knotted construction
While the water-based underfloor heating is not usually impacted by the rugs or carpets, you do have to be more careful with electric underfloor heating. With the latter, a rug could act as an insulator, interfering with the circulation of heat which could potentially lead to a rise in electricity costs. This could be damaging to timber floors which should only be heated to 27°C, making them vulnerable to any tapped heat. A tufted rug or carpet with glued pile which is overheated could possibly result in the glue softening, which coudl in turn cause waves to form in the rug or carpet once the material cools down. This could affect both the rug and the floor.
It’s best therefore to chose a rug that doesn’t retain heat, ideally made from natural fibres without a glued canvas or tufts to avoid blocking heat circulation. A hand knotted rug is the ideal choice. Whilst our hand tufted rugs have their tufts secured by synthetic latex and a canvas glued on the back, all of our designs can also be made in hand-knotted construction, so all our rugs, if hand knotted, are ideal to place over heated floors. Knotted rugs also have the advance of being able to be made at very thin pile (4mm) which is useful in hallways where doors may have to pass over them. Knotted rugs can also be made in thick pile too. The minimum pile height for a tufted rug is thicker around 10mm. See below the pile height difference between a hand tufted rug, with has a canvas glued on the back (left) and hand knotted rug, no canvas (right).
Rug materials, shapes and sizes most suitable for underfloor heating
As mentioned previously, rugs made from natural fibres can be a good fit for underfloor heating systems as they conduct the heat and release it quickly, unlike synthetic fibres so it’s best to choose a rug with wool, silk or hessian materials. All of our rugs are made from 100% New Zealand wool, or Chinese silk, sometimes a mix of the two natural fibres.
When you choose to place a rug on your heated floor, it is best not to cover large areas of the floor, as even the best of materials will still reduce the spread of heat throughout your room. One practical and beautiful alternative is to choose runners. A well chosen runner will bring ambience and style to the room and at the same time, by being narrow, will allow the heat to circulate, not causing issues with the underfloor heating.
If you do choose a rug, instead of a runner, consider its size and the furniture arrangement. With underfloor heating it is best to have an all-off style arrangement (see the image below), where the rug sits in front of, not underneath the furniture, this way allowing the floor to breathe.
The best rug thickness for heated floors
The advice from most heating companies has been to recommend rugs and carpets of a thermal resistance that is less than 1.5 togs. On a practical level, this means that your rug should not have a high pile height as this traps the heat within the fibres – an ideal pile height is 10 – 12mm. Recent research by The Carpet Foundation, in partnership with the Underfloor Heating Manufacturers Association (UHMA), recommend the thermal insulation value should not add up to more than 2.5 togs when the ratings of your rugs (or carpets) are combined with the tog levels of the underlay.
It’s best to seek advice from your your underfloor heating provider if you’re thinking of placing a rug or carpet across a large proportion of your room and be sure to watch out for the tog values of any carpets or rugs you’re purchasing. Consider using natural fibre materials that are hand-knotted and not felt-backed, with lower pile heights that do not sprawl across your entire space. If you’d like any further advice about suitable rugs from our range, please feel free to contact us.