As a homeowner, maintaining a healthy indoor environment is crucial. One common issue many encounter is high indoor humidity, which can stem from various causes and lead to several problems if not addressed properly. This comprehensive guide will help you understand the reasons behind your high indoor humidity and provide actionable steps on how to rectify it.
What Causes High Indoor Humidity?

High indoor humidity often originates from your crawl space. Here are some potential sources:
Opened Crawl Space Vents
Open crawl space vents were once considered a necessary feature to reduce moisture. However, these vents often increase humidity, as the meeting of cool and warm air can lead to condensation and increased relative humidity.
Dirt Crawl Space
While more cost-effective and easier to install, dirt crawl spaces often contribute to high humidity. The moist earth underneath can cause significant humidity problems unless you install a durable water vapor barrier.
Rain and Flooding
Heavy rainfall and flooding can increase hydrostatic pressure on your home’s foundation, leading to additional moisture in your crawl space. Flooding, particularly in areas with distinct wet and dry seasons, can also contribute to this problem.
Why Should I Fix My High Indoor Humidity?
Ignoring high indoor humidity can have several undesired outcomes, emphasizing the importance of finding a solution.
- The Stack Effect: Poor crawl space encapsulation can lead to the stack effect, where air enters from the bottom and exits from the top, carrying moisture, mold spores, and other airborne contaminants.
- Mold Growth: Mold, which can thrive in relative humidity as low as 60%, is a significant concern associated with high indoor humidity.
- Wood Rot: High humidity can also cause wood rot, a type of fungus that rapidly spreads and can compromise your home’s structural integrity.
- Increased Electric Bills: High indoor humidity can make your home feel warmer and put more strain on your air conditioning, increasing energy consumption by 15-25%.
How Can I Fix High Indoor Humidity?
1. Remove Standing Water
- The initial step involves removing any standing water in the crawl space, which continually contributes to humidity.
- Consider using an interior drainage system and a sump pump, and consult a crawl space repair expert for the best solution.
2. Permanently Seal Crawl Space Vents
- Contrary to popular belief, crawl space vents often increase humidity. Closing these vents can help control moisture.
- JES offers crawl space vent covers for this purpose.
3. Install Vapor Barrier System
- Vapor barrier systems are essential in preventing moisture from rising from your dirt crawl space.
- JES recommends the CrawlSeal™ 20-mil crawl space vapor barrier, exceeding the thickness required by most residential codes.
4. Add a Dehumidifier
- Following encapsulation of your crawl space, a dehumidifier can be beneficial in maintaining stable and healthy humidity levels.
- Do note that dehumidifiers alone won’t fix the problem unless other mentioned steps are also taken.



By understanding these causes and solutions, you’ll be well-equipped to lower humidity in your house, ensuring a healthier and more comfortable living environment. Always consult with a professional like JES for personalized solutions for your specific needs.
Take Action with JES
Now that you understand the importance of controlling indoor humidity and how to do it, the next step is to put that knowledge into action.
With JES, you can ensure you get the right home solution. Our team of experts is committed to providing effective and efficient services to encapsulate your crawl space, bringing down your indoor humidity levels to a comfortable and healthy range.
With our crawl space encapsulation service, we tackle all aspects from closing off crawl space vents and installing our robust CrawlSeal™ 20-mil vapor barrier to addressing standing water issues. Our comprehensive approach ensures that you get the best possible outcome, tailored specifically to your home’s needs.
Don’t let high humidity levels compromise your comfort or your home’s health. Contact us today and take the first step towards a healthier, more comfortable living environment. Call JES now and let us help you maintain the optimal humidity level in your home.