The safest setup would be using a oil filled heater and a ranco or johnson thermostat.

I would not rely on the heater's thermostat they can go bad very easily which can make the heater overheat.

Than in case of power outage I have a Buddy Heater hooked to a 20 lbs propane tank (It burns clean and is meant to use inddor) http://www.target.com/p/Mr-Heater-Po...gpa=pla&ci_kw=