there is nothing wrong with using an overhead bulb to boost ambient air temps. It is always highly recommended to use a thermostat to control your temps though. the infrared(red) bulbs work better for most because they can be left on 24/7 without disrupting the snake too much. Others here on this forum have had some luck using deep blue florescent lights as well, but im not to sure where a person could buy those from? maybe other members can give advice on finding those.