I reckon you cannot go past heat cords for safe and efficient heating.
I’d recommend under a slate or ceramic tile. You can choose colour for the effect you want, both are good conductors of heat and so will spread the heat evenly. They also have a high specific heat which means they take a while to heat up but when a cold reptile sits lays on them, they are able to continue giving out heat rather than going cold.
By using a thin piece of MDF the same size as the tile, you can saw or rout straight grooves in it, full length and 2 or 3 cm apart. Repeat at right angles with a few grooves near each edge. Position it in the enclosure at the warm end, either touching the back wall or the end wall. Drill a 5 mm hole through the wall of the enclosure so it comes through where you want the heat cord to enter the wooden base. Insert the cord into the grooves, looping it back and forth and when finished, place the tile on top. The tile can be held with Blutack, wooden edge strip attached to the wooden base or simple metal clips, if desired or needed.
A 15 W cord will give you around 35[SUP]o[/SUP]C. You can reduce the temperature by looping less heat cord under the tile and letting some hang out the back of the cage. Wait till it fully stabilises after you have adjusted it, periodically check your temps and you should not need a thermostat for it (as suggested above). Even if you have a thermostat, you should be checking temps periodically to ensure they are working correctly, so it really isn’t any more effort required.
Blue
