What kind of underlay is suitable for underfloor heating?
If you have underfloor heating, then you will have to make sure that both your carpet and your underlay have a suitable tog-rating (see under Other Things To Consider).
Too high a tog for either of them may cause problems - for example, the heating system will switch off prematurely, as the temperature under the carpet will be higher than the room due to the trapped heat.
The consensus is that the combined carpet and underlay should have a tog value of 2.5 or less. Finding this combined value is quite straightforward - a good rule of thumb is to add the values of both carpet and underlay together, then subtract 1. Again, this is covered in more detail on this blog post.
Find our selection of high-quality polyurethane underlays on the Accessories Page