Heatmats I think heat 3-5c higher than ambient temperature , so watch they not on in warm summer temps or on on temp spikes , you will melt the tray or worse
Also a thin piece of reflective insulation under mat is more effient so no loss of heat to floor
The reptile people make excellent controllers for them to eliminate this and keep temps steady all year round , cheap secondhand on eBay etc
I use Habistat ones , but check min and max wattage usages befor purchasing and match with what you using , some are pulsing ( switch on and off ) and some are dimming , both great