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How To Reduce Humidity In Your House

Jul 29, 2022



One of the key signifiers that we’ve entered late summer in the DC metro area is high humidity. You know the feeling — stepping outside into thick, hot, damp air, and immediately regretting leaving the comforts of your air conditioned home. But high humidity isn’t just a problem you have the deal with outside of the home. Maintaining a proper indoor humidity level is key to comfort, air quality, and the wellbeing of your home. 


We’ll explain how to measure your home’s indoor humidity level and how to reduce humidity in your house to increase comfort and keep your home in top condition all summer long. 

What is Indoor Humidity?                             

Indoor humidity refers to the amount of moisture in the air in your home, which plays a critical role in air quality and overall comfort. It’s important to maintain the right level of humidity in your home — when humidity levels are too low, dry air can cause breathing problems and skin discomfort, as well as damage to wooden components of your home like floor boards, door and window frames, etc. When humidity levels are too high, your home becomes susceptible to mold and mildew growth in air vents, plus damage to drywall. 

How Can I Check Indoor Humidity?

Most modern thermostats display a humidity percentage to allow homeowners to easily check humidity levels. However, if you don’t have a digital thermostat or your particular thermostat doesn’t measure humidity, there a few alternative solutions that can help. 


The first is a hygrometer, which you can buy on Amazon or at Walmart for around $10. This device is designed to measure water vapor in the air and can provide a reading of indoor humidity percentage similar to the one you’d get from a digital thermostat. 


Another test you can run to determine if your home’s indoor humidity is too high is the ice cube test. Here’s how it works: Add a couple of ice cubes to a glass, add water, and stir. Then wait a few minutes. If after three or four minutes moisture does not form on the outside of the glass, your indoor humidity level is too low. If the glass is dripping with excessive condensation, your humidity level is likely too high. While this test won’t provide an exact humidity percentage, it can indicate if there’s an issue with your home’s indoor humidity that needs to be addressed. 

What Is Ideal Home Humidity?

According to the Mayo Clinic, the ideal indoor humidity for health and comfort is somewhere between 30 and 50%. If your thermostat reads below 30% humidity, the air in your home is too dry and you may want to consider purchasing a humidifier to help improve air quality. If your reading is consistently above 50%, you should investigate ways to reduce the humidity level in your home. Consistently high indoor humidity can cause damage to your home’s structure over time, not to mention increase your risk of health issues caused by mold and mildew growth. 

Symptoms of High Humidity In Your Home

If you suspect your home’s indoor humidity level may be too high, but aren’t sure because you haven’t been able to get an accurate measurement, look out for these signs:


  • Balmy air
  • Foggy windows
  • Mildew smell
  • Visible mold growth 
  • Wood rot
  • Rusting door and window hinges
  • Worsening allergies 


If you’ve noticed any of these symptoms of high humidity in your home, call an HVAC professional to help you put together a dehumidification plan. 

Why Is My House So Humid? 4 Common Causes

If your indoor humidity is too high, you may be wondering why that is, and how you can go about solving your humidity problem. Here are some common causes of high humidity in your home:

Frequent Use of Water Appliances

Humidity levels increase when moisture is introduced into your home, and a big way that happens is when you run hot water or use appliances that run hot water and cause steam to be released into your home. Frequent hot showers, running the washer and dryer, even boiling water or cooking can contribute to high moisture levels in your home, raising your indoor humidity level.


Luckily, these usually result in only a temporary increase in humidity, so as long as your home is well-ventilated, you shouldn't have any long-term issues.

Poor Ventilation

On the other hand, if your home does not have sufficient ventilation, moisture can become trapped over time and lead to damaging, high humidity levels. Not only is ventilation required to keep humidity levels in check, but it’s also critical to maintaining healthy air quality for your loved ones. When air cannot properly circulate, pathogens can build up and spread illness and infection, which can be especially harmful if you or a family member suffers from asthma or other respiratory issues. 


If you’re concerned about the ventilation system in your home, consider calling a professional to conduct an air quality audit and help you build an air quality improvement plan to ensure your home and loved ones are safe and comfortable. 

Damp Weather

Since indoor humidity levels rise when moisture enters the home, it makes sense that your home humidity spikes with rainy weather. The more humid and damp it is outside, the more likely it is that your indoor humidity will increase as well. If your indoor humidity only increases when there’s an occasional summer storm, you shouldn’t worry about long-term damage. However, persistent inclement weather can have effects if you don’t take action to combat it. 

Plumbing Issue or Leak

Another internal source of humidity to be weary of is moisture caused by leaks or other plumbing malfunctions. Over time, water trapped between or behind walls makes its way to the surface and can lead to higher indoor humidity levels. Hopefully, other signs of a leak like dripping sounds, staining and even visible mold would appear before you feel humidity as a result of a leak, as the damage would have to progress to an advanced stage to impact air quality. If you suspect a plumbing issue may be the culprit, call a plumber ASAP. 

HVAC Malfunction

Controlling indoor humidity is part of your air conditioner’s job, so when your house feels damp with AC on, it’s a clear indicator that something is not right. There are a few possible reasons why your indoor humidity is still high even with the HVAC running, including improper unit sizing and dirty evaporator coils. An HVAC expert will be able to diagnose and repair any air conditioning issue that may be causing high humidity in your home. 


Read more: Why Is My House So Humid With the AC On?

How to Lower Humidity In Your House

Most of the time, indoor humidity issues can be easily solved without professional help. Let’s dive into how to reduce humidity in your house:

Run Your AC More Often

Many homeowners try to minimize air conditioning use to help keep energy costs low throughout the summer, but if you’re noticing home humidity becoming an issue, it’s important to run your HVAC every once in a while. 


Check your AC’s fan settings and make sure they’re set to AUTO, not ON. The AUTO setting is more energy-efficient and allows moisture to drain effectively. The ON setting allows the fan to run even when your AC isn’t in cooling mode, so all of that moisture ends up getting pushed back into your home. 

Minimize Hot Water Use

Taking cooler, shorter showers, running the washing machine less frequently, drying your clothes outside and grilling or opting for outdoor cooking are all simple ways to reduce indoor moisture, especially on days where outdoor humidity is high and already contributing to high indoor humidity levels. 

Get a De-Humidifier

One of the best indoor humidity control solutions is a dehumidifier — it’s literally designed to eliminate moisture from the air in your home. There are a few factors to consider when choosing the right dehumidifier for your home, such as home size, cost, noise level, etc. If you need help deciding what type of dehumidification system works best for your home, talk to the experts at CroppMetcalfe. We can provide a recommendation that works for your home and family. 


Read more: How Does a Dehumidifier Work?

Trust CroppMetcalfe to Solve Your Indoor Humidity Problems

CroppMetcalfe’s expert team of HVAC and home performance professionals are here to help answer any dehumidification questions your may have. We can diagnose and provide a solution for any home humidity issue — just call our 5-Star Technicians at 1-888-304-0678 or submit a service request online today!



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