A house can be at the right temperature and still feel damp and uncomfortable. That's humidity, and near the coast it's a common complaint. Here's what's going on and what helps.
What indoor humidity should be
A relative humidity of roughly 30 to 50 percent indoors is comfortable for most people and discourages mold and dust mites. Above about 60 percent, a house starts to feel clammy and mold gets a foothold. An inexpensive hygrometer from a hardware store tells you where you are.
Your air conditioner already dehumidifies
As air passes over the cold indoor coil, moisture condenses and drains away. That's the water in your condensate drain. But an air conditioner only removes moisture while it's running, and only if the air moves slowly enough over the coil.
Why the house still feels muggy
- The system is too big for the house. It cools the air quickly and shuts off before it's had time to remove much moisture. See what size system you need.
- The fan is set to On. Between cycles, the fan blows across a wet coil and puts moisture back into the house. Set it to Auto.
- Mild, damp days. On a cool, foggy morning the AC barely runs, so it barely dehumidifies.
- Moisture coming in: a damp crawlspace, leaky ducts drawing in outside air, showers and cooking without exhaust fans.
What helps
- Use the exhaust fans in bathrooms and the kitchen, and let them run a while after.
- Set the fan to Auto.
- Keep up maintenance: a clean coil and the right refrigerant charge remove more moisture.
- A dry mode, if your ductless system or thermostat has one, runs the system to dehumidify without over-cooling.
- A whole-home dehumidifier connected to the ductwork handles moisture on days the AC doesn't need to run.
- Fix the source: a vapor barrier in a damp crawlspace, sealing leaky ducts.
Too dry is a problem too: in winter, very low humidity means dry skin, static and cracking wood. If your home swings between the two, ask us about humidity control. Call 805-965-6326 or send us a message.
Related
More tips on air quality, cooling.