Depends on how many animals you have, if you are breeding and have an incubator running etc

For a few snakes some warmers used to ship reptiles are a good thing to have.

If you have a room full of snakes a buddy heater (which burns clean) http://www.amazon.com/Mr-Heater-F232...s=buddy+heater is a great inexpensive solution when use with a 20 lbs cylinder

And of course for both snakes and incubator you may want to invest in a generator.

I have both buddy heater and generator.