You can use fluorescent lights if you only need to increase the air temperature a few degrees, or if you need to increase the air temps a little more the combination of a fluorescent tube and a radiant heat panel (which doesn't directly increase the air temperature inside the cage but will increase the air temperature a few degrees) can boost the air temps 5-10 degrees. There is no reason to heat a whole room for plastic reptile cages. Worst case you can cut a hole in the top and screen it off and use a heat lamp/CHE.