Why does my floor get warmer in some spots?
Loose Wire – NADWS
Your floor can reach higher temperatures in some areas where furniture, area rugs, dog beds or other fixtures are trapping the heat. Avoid placing thick mats, rugs and floor level furniture on your heated floor, specifically in the area where the sensor probe is located. These restrict the transfer of heat away from the cables and result in the floor area beneath them being warmer than other areas.
Warmer spots can also be caused if wire spacing is closer in some parts than others. Make sure the wire is spaced consistently at the time of installation.