How it works
The best level varies with outdoor temperature, construction, and occupant comfort. In cold weather, a home may need lower humidity to prevent water from condensing on windows and walls.
What people often miss
Use a hygrometer to measure rather than guess. Fix water leaks and ventilation problems before relying only on a dehumidifier.
Why this question comes up
Dry winter air and muggy summer rooms make humidity a seasonal concern.
Key points
- A practical indoor relative-humidity target is generally below 60 percent, with roughly 30 to 50 percent comfortable for many homes and helpful for limiting condensation and mold.
- The best level varies with outdoor temperature, construction, and occupant comfort. In cold weather, a home may need lower humidity to prevent water from condensing on windows and walls.
- Use a hygrometer to measure rather than guess. Fix water leaks and ventilation problems before relying only on a dehumidifier.
Bottom line
A practical indoor relative-humidity target is generally below 60 percent, with roughly 30 to 50 percent comfortable for many homes and helpful for limiting condensation and mold.
Source and verification
This Answer was checked against EPA Mold and Moisture Guidance. Follow the source for the full official explanation and any later updates.