With our changing climate, more people are having to deal with higher humidity for longer periods of time. I’d say this past summer was probably the worst for humidity since I moved to Georgia in the summer of 2000. The map above shows dew point temperatures across the U.S. at the time I began writing this article on a July afternoon, with some very high numbers on the eastern side of the country.

So, how do you stay comfortable in your home when the outdoor humidity is so high? Let’s take a look at some options…and I’ve got nine things you can do before you crank up that dehumidifier.

1. Keep doors and windows closed.

This one seems like it should be a no-brainer, right? If the outdoor humidity is high, don’t let it get into the house. (If you don’t have air conditioning, that’s a different story.)

When you’re not sure if it’s too humid to open the windows or not, you can follow the guidance I gave in this article. In short, my advice there was to look at the outdoor dew point temperature. If it’s above 60 °F (15 °C), close ’em!

2. Run the bath fans and range hood only enough to do their jobs.

When you’re generating moisture or indoor air pollutants in bathrooms or the kitchen, running those exhaust fans is a good thing. But too much of a good thing can be bad. When exhaust fans keep running, they begin to bring in air that’s more humid than the air they’re exhausting.

To help limit their operation, use a timer on your bath fans or pay attention to when you think it’s OK to turn off the fan. But please do use the range hood when you’re cooking to help your indoor air quality.

3. Keep pots covered when cooking.

Many range hoods have poor capture efficiency. Take a look at your range hood when you’re boiling water with the range hood turned on and see how much of the steam spills out of the hood. It’s not pretty. You can limit the amount of water vapor that gets into your indoor air from cooking by keeping pots and pans covered when suitable.

4. Take shorter showers and baths.

Another source of indoor humidity comes from the bathroom. Every time you shower or bathe, fast-moving water molecules go from the liquid to vapor state.

The longer that hot water comes out of the shower head or sits in the bathtub, the more that conversion happens…and the higher your indoor humidity goes.

5. Seal the big air leaks in your attic and crawlspace.

This is like number 1 in this list…except the “windows” and “doors” are open 24/7. Find the big holes and seal them. Then go for the medium-size holes and finally the small holes. (Read more about air sealing here.)

If you’re not able to or don’t want to go into the attic or crawlspace to do this, hire a company to do it for you. This is some of the lowest hanging fruit to make your house more comfortable, energy efficient, healthy, and durable.

6. Seal the leaks in your duct system.

Duct leakage can add more moisture to your indoor air, too. When the return ducts leak in unconditioned spaces like attics or crawlspaces, they suck in the humid unconditioned air near the leaks. Yes, it passes through the air conditioner, which can remove some of that moisture. But the extra moisture load means the AC might not be able to dehumidify enough.

The other way duct leakage can make your house more humid is if the leakage outside the conditioned space is unbalanced. By that I mean that the ducts leak either more on the supply side or more on the return side. If the supply ducts leak more than the return ducts, the pressure inside your house becomes negative relative to outdoors. That causes outdoor air to infiltrate, bringing all its humidity with it. (For a more complete explanation of this phenomenon, see my article explaining duct leakage. And for ductwork best practices, read Martin Holladay’s “Leak-Free Duct Systems.”)

7. Experiment with the thermostat setpoint to find your comfort sweet spot.

One way to dehumidify more is to lower the setpoint on the thermostat. But if you lower it too much, you end up with a house that’s cold and clammy. That’s not comfortable.

So get yourself a digital thermo-hygrometer*—with remote sensors if you want to measure the temperature and relative humidity in multiple places. Try different settings on the thermostat and watch what happens to the temperature and relative humidity. To get a better handle on what’s happening with the humidity, get an app that can convert those numbers to the dew point temperature.

8. Make sure the fan on your air conditioner is set to “auto.”

There are two good reasons you don’t want the fan on your central air conditioner to run continuously in a humid climate. First, the air conditioner gets cold and condenses water from the air passing over the coil. When that water drips down and drains away, the AC has helped dehumidify your indoor air.

But when the compressor goes off, the coil warms up. If the fan keeps running then, the coil isn’t cold enough to condense water from the air. Worse, the air blowing over the coil causes the water that’s still sitting there to evaporate back into the air, raising the relative humidity in your home. I know because I saw this in my own house (graph below, details here).

Second, leaky ducts can create more infiltration. With the fan running continuously, the ducts leak continuously. See number 6 above for why that can make your home more humid.

9. Get an HVAC professional to check your air conditioner’s airflow.

How well an air conditioner dehumidifies depends on a number of factors. An important one is how fast the air moves across the coil, called the airflow rate. In humid climates where dehumidification is important, you want that airflow rate to be about 350 cubic feet per minute (cfm) or less.

Measuring the airflow rate takes equipment and skills that most homeowners don’t have, so you’ll probably have to call an HVAC pro to do that measurement for you.

10. Use a dehumidifier.

Finally, if you’ve done all you can or are willing to do, it’s time to use a dehumidifier. The one below is a whole-house dehumidifier that can pull the air from one place and send the dehumidified air somewhere else. You also could use a regular room dehumidifier.

And there you have it. In summary, first you reduce the amount of moisture you’re adding to your indoor air (items 1 through 6). Then you optimize the mechanical systems to get the humidity where you want it.

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Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Georgia. He has a doctorate in physics and is the author of a bestselling book on building science. He also writes the Energy Vanguard Blog. For more updates, you can follow Allison on LinkedIn and subscribe to Energy Vanguard’s weekly newsletter and YouTube channel. Photos courtesy of author.