Updated November 1, 2026 · Reviewed for accuracy by a licensed Uniform HVAC technician before publication
Different jobs
| Air conditioner | Whole-home dehumidifier | |
|---|---|---|
| Main job | Lower temperature (and remove moisture while cooling) | Remove moisture without much cooling |
| Works best when | It's hot and the system runs long cycles | It's humid but mild, or the home is empty |
| Controlled by | Thermostat temperature | A humidity setpoint (dehumidistat) |
| Water | Condensate drain | Its own condensate drain |
When a dehumidifier helps
- Humidity stays above 60% even with a properly working, right-sized AC
- Seasonal homes kept closed at a higher setpoint
- Very efficient or well-sealed homes with low cooling loads
- Rooms with high moisture sources
When it doesn't
If humidity is high because of a fan setting, airflow, duct leaks or a short-cycling system, fix that first. A dehumidifier fights the symptom; the HVAC fix removes the cause.
Installation basics
- Sized to the home's moisture load, following the manufacturer's guidance
- Ducted to supply and return, or a dedicated return
- Its own properly trapped condensate drain
- A dedicated control with a humidity setpoint
Specifications vary by manufacturer; your technician will reference the installation manual for the unit chosen.