Underfloor heating is one of life's quiet luxuries — but many homeowners worry that adding a rug will either block the heat or damage their floor. The truth is more nuanced, and with the right knowledge, you can absolutely enjoy a beautiful rug over UFH without compromise.
The key metric: tog rating
Heat generated by UFH needs to pass through your rug and into the room above. A rug's resistance to heat transfer is measured in 'togs' — the same scale used for duvets. Most UFH manufacturers recommend a combined tog rating (rug plus underlay) of no more than 1.5 togs, and ideally under 2.5 togs. Exceeding this can cause the heating system to work harder, increase energy bills, and in electric UFH systems, potentially cause overheating.
As a rule of thumb, the thinner and less dense the rug, the lower the tog value. Flat-weave rugs and low-pile designs are generally the safest options.
Best rug types for underfloor heating
Flat-weave rugs — kilims, dhurries, and similar woven designs — are excellent for UFH. Their low profile allows heat to pass through freely and they're typically well within safe tog ranges. Many of Kelaty's flat-weave collection are perfectly suited.
Low-pile wool rugs (under 10mm) are also a good choice. Wool is naturally temperature-responsive and doesn't trap heat in the same way a thick synthetic pile might. Avoid rugs with very thick, dense piles or heavy hand-tufted constructions, which retain more heat.
Handmade rugs with a cotton or jute weft base also tend to perform well, as the natural fibres allow better airflow than dense latex-backed constructions.
Underlay and UFH: what to use
Standard foam or rubber underlays can restrict heat flow and are not recommended for use with UFH. Instead, look specifically for UFH-compatible underlay — typically a thin, open-weave felt or a perforated foam that allows heat to pass through freely. These are now widely available and make a significant difference.
Avoid any underlay with a solid rubber or PVC backing if your UFH is electric — these materials can retain heat and create a risk of system damage or flooring distortion.
Acclimatisation and placement tips
When laying a new rug over UFH, turn the heating off or down to its lowest setting for 24–48 hours, then gradually bring it back up to normal temperature. This allows both the rug and the floor beneath to adjust without thermal shock — especially important for natural wood floors which can contract or expand with rapid temperature changes.
Avoid placing very large rugs over UFH that cover the entire floor — leaving some exposed perimeter allows heat to circulate more freely into the room.
For interior decorators specifying UFH spaces
When specifying rugs for clients with UFH, always request tog ratings from suppliers and factor in the underlay contribution. Kelaty's team can advise on suitable options from our range and confirm tog ratings on request — just ask when ordering.
The right rug and the right underlay working together means you don't have to choose between warmth and style. Browse our UFH-friendly collection or speak to our team for tailored advice.