Indoor Air Quality
How Do I Reduce Humidity in My House?
The short answer
Des Moines summers are genuinely humid — dew points often climb into the 60s and 70s — so even a well-running AC can leave a home feeling sticky. The most effective fixes, in order: make sure your AC is correctly sized and well-maintained, ventilate the rooms that create moisture (bathrooms, kitchen, laundry), and add a whole-house dehumidifier if the AC alone can't hold indoor humidity in the comfortable 30-50% range.
Why indoor humidity matters
Humid air feels warmer than it is, so you crank the AC lower and run up the bill while still feeling clammy. Beyond comfort, sustained high humidity invites mold and dust mites, can warp wood floors and trim, and leaves a musty smell that no amount of cleaning fully clears.
The comfortable target for most homes is 30-50% relative humidity. In an Iowa summer, aim for the lower-to-middle of that range; in winter, slightly lower (around 30-40%) helps limit condensation on cold windows.
What's making your house humid
A few usual suspects drive up indoor moisture:
- An oversized AC that short-cycles — it cools the air fast, then shuts off before it can wring out much moisture.
- A dirty coil, clogged filter, or low airflow that keeps the system from dehumidifying properly.
- Poorly vented moisture sources: showers, cooking, and laundry with no exhaust fan running.
- A damp basement or crawlspace feeding moisture into the rest of the home.
- Air leaks and gaps that pull muggy outdoor air inside.
Ways to bring humidity down
Work from the simplest fixes toward the bigger equipment changes:
- Run bathroom and kitchen exhaust fans during and after showers and cooking.
- Keep up with filter changes and an annual AC tune-up so the system dehumidifies as designed.
- Seal obvious air leaks and address a damp basement or crawlspace.
- Have the system checked for correct sizing — an oversized unit is a common, fixable cause of stickiness.
- Add a whole-house dehumidifier when the AC keeps the temperature right but the air still feels damp.
Common misconception
Cranking the thermostat down will dry out the air.
The local truth: Running colder doesn't equal drier. An oversized AC actually leaves a home more humid because it cools the air quickly and shuts off before removing much moisture. Right-sizing and longer, steadier run times matter more than a low set point.
Frequently asked questions
What humidity level should my Iowa home be in summer?
Aim for 30-50% relative humidity, ideally under 55% in summer. In winter, a bit lower (around 30-40%) helps prevent condensation on cold windows.
Why is my house humid even when the AC is running?
Usually it's an oversized unit that short-cycles, a dirty coil or filter, or low airflow. Sometimes the cooling load is light enough that the AC doesn't run long enough to dehumidify, which is where a dehumidifier helps.
Can a dehumidifier help lower my cooling costs?
Drier air feels cooler, so many homeowners stay comfortable at a slightly higher thermostat setting. Actual savings vary from home to home.
Still feeling sticky in Des Moines?
If your home stays muggy no matter the thermostat, our team can check sizing, airflow, and your options — including a whole-house dehumidifier. Maintenance plans keep the system dehumidifying season after season.