Humidity Control for your Home in the Summer

Learn why humidity control is important during the cooling season.

The Basics and Benefits of Removing Humidity from your Home

When it comes to cooling your home in some regions of the country, humidity control is as big of a problem as high temperatures. Unlike the arid Southwest, the Southeast and parts of the Midwest have very high humidity in the summer months and this can result in higher than necessary energy bills if you aren’t careful.

Humidity is behind the “heat index” you hear on the weather report and drives the “feels like” temperatures that are usually several degrees hotter than the actual temperature. Selecting and properly sizing your air conditioning equipment to deal with humidity is a little more difficult than just getting something that keeps you cool on the hottest days.

The Basics of Removing Humidity

Most central air conditioning systems are capable of removing humidity from the air in your home. Window units or ductless systems do not generally move enough air through the system to remove the humidity evenly from your entire home. While most central AC systems will work, effectively controlling your humidity so you’re comfortable day and night is best achieved with a high efficiency system.


  • To remove humidity, an air conditioner has to be running. Basic, minimum 13 SEER systems typically run in either “on” or “off” mode. High efficiency systems (16 SEER and up) usually provide variable speed capacity which can run longer on lower power, giving the system more time to remove humidity.
  • High efficiency systems are able to control the temperature more precisely, eliminating noticeable cold or hot swings and not allowing humidity to build up in the air.
  • Because the air is constantly being conditioned with a high efficiency system, there is much less chance of stagnant humid air causing mold in the walls or attic.

Additional Benefits

In addition to the added comfort you’ll feel with a high efficiency system capable of removing humidity, they also run much more quietly, which can be a benefit at night when you’re trying to sleep. Because they run on variable speed, high efficiency systems are also much more energy efficient, which translates to money saved every month on the energy bill.

The Bottom Line

If you live in an area of the country that is naturally humid, talk to your contractor about humidity control and higher efficiency systems that can provide you with a comfortable environment, not just cold air.

Watch this video to learn more about the comfort and health benefits of high efficiency AC systems.

After reading this are you more or less likely to explore a high efficiency system? How important is humidity control in your home?


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29 thoughts on “Humidity Control for your Home in the Summer

  1. Hi. I had a new roof put on with vapor barrier under shingles. The contractor also put in a roof fan with a humistat/thermostat. The manufacture says to set the controls at 70% humidity and the temp at 105 .

    I live in Northern NJ, near NY/PA border. I wonder is this a good control for my roof? I never had a fan just a vent. I still have soffit vents and the contractor said I would benefit from the electric roof fan? I thought I had enough ventilation with the roof vent and the soffit vents but he said because of the new roofs and vapor barrier I needed a roof fan.

    Should I change the humistat control lower for winter and what about summer?


    • Humidity should be 40-50% for most zones, below 50% is better. So yes that is ok, but as the climate cools off, you may want to reduce it further to <40% to prevent condensation problems. A simple RH indicator is a cheap way to keep potential moisture problems in check.

  2. I live in Massachusetts. Very often my finished basement humidity reaches 70% and starts to smell musty. I have a free standing dehumidifier and at best brings down the humidity to 62%. The rom is 900 sq ft. Can I use a humidistat that attaches to my a/c thermostat basements thermostat?

    • We recommend staying with the setup you have. The central AC is not designed to manage the basement humidity, its primary function is for comfort cooling. If the current dehumidifier is not able to keep up, you may look at investing in a larger one.

  3. We have recently moved to the west Texas area where the outdoor humidity level this summer is around 14% with temperatures around 100/109. Our indoor humidity level was even lower while using the a/c which has not been able to keep the home cool. Average indoor temperatures are around 86 with the a/c running full blast. I have started using an indoor cool humidifier to add humidity to the living area. I was worried about our health and our wood cabinets and furniture. My friend said running a humidifier and a/c at the same time defeats the a/c from running efficiently. We feel much cooler with the humidifier on and the home seems to be cooler when using it. Should we not use a humidifier and a/c at the same time?

  4. We live in Tennessee and just bought a new heat a/c system for our 2 story home….2 systems; one in attic upstairs (14 seer Rheem) and one in the tall crawl space beneath the house (14.5 seer Rheem.) The problem is that although the downstairs unit is cooling well, the humidity level is 69% and I am smelling a musty odor now. The old system wasn’t like that. What could our problem be and how to fix/adjust? We do not have a dehumidifier on our unit….they told us that we could put a fan in our crawl space and take care of 80% of the problem like that, rather than spend the large amount of money ($2,895) on a dehumidifier attached to that unit.

  5. We are having a home built in Florida. Our builder gave us the option of buying one or two ac units with humidity control. He said, “If money was really an issue we could buy one humidity control unit and one regular unit”. My question is, if we go ahead and spend the money on just one humidity control unit would it be most efficient to have that unit service our upstairs living area where all the bedrooms, bathrooms and laundry area is or should it be downstairs where we have just one powder bath and the kitchen, breakfast area great room and office?

    • Hi Jeanne, I assume by a “humidity control unit” the contractor is talking about is a variable capacity or two stage AC system. If so, it might be best to have that unit upstairs where you will likely be when the ambient temperature goes down outside but you still need the run time to get the moisture out of your space. When it is really hot out, your downstairs system is going to running long enough to circulate the air and getting the moisture out. In any case, I would consider putting a 16 SEER or greater, two stage system in the upstairs space to keep the temperature right and humidity low at night and in the morning when it is not really hot out yet. hope this helps.

  6. Frank I would like to offer some thought on humidity, I am from the Dallas area, I am in the restoration business, I agree a AC solution is a valid solution in many cases, but an AC unit cannot cover all the bases, we know that the RH in some parts of the country is 70% or better 200 days a year, and as the best of units generally will remove 30 to 50 % during a single air change this does not account for the Stack effect, some homes have a stronger effect than others. so when the energy envelope is open either at top with attics or top and bottom as with a crawlspace this changes everything, Just saying, look at the entire home system not just the AC, I do believe this open forum is a great way to inform people, and you do a great job at it. thank you T.

  7. I live in CA High Desert
    Have swamp cooler in 1580sq ft mobile home
    Temperature is 56 and 88% humidity!
    Driving up my chronic back pain so I can not function and
    Can barely move
    How can I bring down humidity?!
    Moved from No CA, always had central heat and air units don’t recall this type of pain
    How can I lower indoor humidity
    To lower my pain?

  8. This is a helpful article. I live in Minnesota and we leave for two cold winter months. I am looking for a humidity sensor to connect to my bathroom fan. And I want that fan to turn on when the humidity is high(above 30% at 10degrees Fahrenheit. My goal is to not run the bathroom fan continuously for two months, but have it come on and go off as necessary. Can you suggest a product for me? I am looking for a switch to replace the manual bathroom fan switch and need a sensor that is sensitive enough to measure humidity levels at low levels. We need to prevent condensation on living room windows and invisible condensation within walls. Thanks.

    • Hi Robert – This is an interesting question. I did a quick internet search using the terms, “humidity sensor switch” and found a lot of options which might work for you and some were available at retail hardware stores. Another thought might be to (also) consider using a portable dehumidifier and have it set up to pour the condensate into a drain instead of into an accumulation container. I know this might be a problem at very low temperatures with frozen drain lines but maybe the humidity levels would not be too high when it is that cold or could add a small auxiliary heater by the dehumidifier. I hope these suggestions help you with your HVAC project!

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