Deep heat projector

A deep heat projector, sometimes called a DHP, is a heat bulb designed to emit infrared wavelengths that penetrate further than a standard basking bulb, warming an animal more the way natural sunlight does rather than just heating the surrounding air and surface. Some keepers use them as a daytime basking source instead of a standard incandescent bulb, particularly for species that bask in open, intense sun in the wild.

Deep heat projectors typically run in a ceramic-rated dome fixture similar to a ceramic heat emitter, since they also produce meaningful heat without much visible light output, and like any bulb-based heat source they need a thermostat to hold a consistent basking temperature rather than running unregulated. They are often chosen for larger enclosures or species that need a strong, focused heat source rather than diffuse warmth.

A common point of confusion is mixing up a deep heat projector with a standard basking bulb or a ceramic heat emitter, when the three behave differently, since a basking bulb provides light and surface heat, a ceramic emitter provides heat with no light, and a DHP is built for deeper penetrating warmth with only a faint glow. Choosing the wrong one for a species' actual needs, or skipping the thermostat that keeps any of them in a safe range, are the most frequent setup errors.