I have brewed saisons into the 30's (ambient) with nothing more then a 40 watt bulb in a chest freezer as heat. To answer your question OP, if you're mostly doing ales and lagers in a fairly stable ambient temp...No. You do not need a heat source. If you want one anyway, a 40 watt bulb is far less dangerous, and far more efficient then a 1000 watt hairdryer or a space heater. Another option is an aquarium heater, or a heating pad. If your ferment chamber is well insultated and sealed, that should be all the heat you need.
I get scared when I'm always reading about space heaters and unsupervised hair dryers in enclosed spaces. Better check the smoke detectors while building that out is all I can say.
I get scared when I'm always reading about space heaters and unsupervised hair dryers in enclosed spaces. Better check the smoke detectors while building that out is all I can say.