Yes—UV-C kills mold spores and surface growth on direct contact. It's used in HVAC systems, water treatment, and some air purifiers for exactly that reason. But UV won't solve a mold problem in your home on its own.

How UV-C works

UV-C damages DNA in mold cells and spores, stopping them from reproducing. Germicidal lamps around 254 nm are the standard. UV-A and UV-B aren't useful for this—you need UV-C.

Airborne spores passing through a UV chamber can be inactivated in seconds. Surface mold needs longer exposure—often many minutes—and only where the light actually hits.

Where it actually helps

UV-C works well in controlled setups: HVAC coils and ducts (preventing growth on wet surfaces), drinking-water treatment, and air purifiers that force air past a lamp. A handheld UV-C wand can treat visible mold on an accessible wall or tile—if you hold it close and long enough.

What UV can't do

UV doesn't penetrate drywall, carpet, or insulation. Mold inside a wall stays untouched. It also doesn't remove dead mold—and dead mold can still trigger allergies. There's no lingering effect once you turn the lamp off; if moisture remains, mold comes back.

Consumer "room sanitizers" are hit-or-miss. Effectiveness depends on lamp power, room size, and whether air actually circulates past the light. Don't expect a plug-in device to replace finding and fixing the leak.

Fix the moisture first

Mold needs water. Fix leaks, run a dehumidifier, improve ventilation, and remove soaked materials. Then scrub or cut out affected areas. UV can be a useful add-on for HVAC or surface treatment, but moisture control and physical cleanup come first.

Safety

UV-C burns skin and eyes. Run lamps only when the room is empty, wear UV-rated goggles if you're operating a wand, and check whether your device produces ozone—which you don't want to breathe.