Incandescent bulbs used to light a room may be hard to come by in the U.S.A. Especially 40, 60, 75 and 100w.
Most replacements are LED.
View attachment 2125014 . They
DON'T put out heat.
You can get Halogen bulbs, they
DO put out heat and can be used in a reflector to concentrate heat downward.
View attachment 2125011
Higher wattage = More heat.
You can still get Incandescent specialty bulbs, like the Red bulb for reptiles that
@aart uses.
Whatever you get, don't exceed the maximum watts for the reflector.
View attachment 2125025
This reflector has a plastic base and maximum watts are 150.
Halogen bulbs put out more heat per watt than incandescent, so go by the higher equivalent number.
The reflector I use for my brooder has a ceramic base and is rated for a maximum 300 watts.
View attachment 2125072 GC