We do not recommend putting a litter box in direct sunlight, in front of a heating element, or above underfloor heating. Not only do warmed faeces smell more, they also form an ideal breeding ground for bacteria. Underfloor heating is usually not installed throughout the entire home but if the litter box does have to be positioned above underfloor heating, a solution could be to raise it above the floor slightly or stand it on a piece of insulation material (polystyrene foam) to shield it from the heat.