The Ultimate Guide to Under-Mattress Moisture Control

Living in confined spaces like RVs, boats, or tiny homes presents unique challenges, such as moisture buildup under the mattress, leading to problems with mold and mildew. 

Various products have been designed to address this issue, each employing different methods to control moisture. While they all aim to solve the same problem, distinctions in cost, guarantees, and customer reviews set some apart from the rest. 

All four products compared work in the same basic way. They lift the mattress off the support platform, keeping bedding away from the cold wet surface, and they allow air flow under the mattress, to dry out any trapped moisture.

The following comparison will explore these differences, guiding you towards options that offer both effectiveness and value, and helping you make an informed decision tailored to your specific needs.
Our Observations:

  • Controlling Condensation, Elevation, and Airflow: All four products excel in these areas, providing control over condensation, elevation of bedding, and under-mattress airflow. They offer essential features to ensure that the mattress stays dry and comfortable.

  • Eco-Friendly Options: Den-Dry is the only option that includes recycled materials, while Coconut Coir stands out with its use of organic materials. If environmental consciousness is a priority, these two products would be your top picks.

  • Customization and Convenience: Den-Dry, Hypervent, and Coconut Coir allow you to trim the underlay to fit your mattress size, offering customization. Furthermore, Den-Dry, Hypervent, and Coconut Coir come ready to use with no assembly required.

  • Size and Spring Support: Froli Star seems to be the only option without a trim-to-fit feature but does offer spring support, a feature lacking in other products. Hypervent is not available in standard sizes but only by-the-foot.

  • Warranty and Shipping: Den-Dry is the only product that offers lifetime and satisfaction guarantees, free shipping, and discount programs. Coconut Coir also provides free shipping.

  • Customer Reviews and Ratings: This one was a bit tricky, all four products are highly rated. Den-Dry has a rating of 4.7, and Coconut Coir at 4.2. These were rated on Amazon. Hypervent at 4.8, and Froli Star at 4.85 were rated on their own websites. Den-Dry boasts a substantial number of customer ratings, making it by far the most reviewed product.

  • Price Point: Prices range significantly across the products, with Den-Dry being the most affordable at $109.95 for a queen size bed, followed by Hypervent at $130.50. Froli Star is the most expensive option at $398.00, while Coconut Coir sits in between at $246.40.
Mold Contaminated Mattress
Extreme Case - Health Hazard
Solving the Problem

No matter what one does, when warm moist air, meets a cool surface, condensation will form. The only way to beat condensaton is to give the moisture a way out, and keep it out of your bedding. Especially, your expensive mattress. Other useful ways for controlling humidity in your outdoor living space includes using the air conditioner; it automatically dehumidifies, and having small low-power fans to promote air circulation.


Selecting the right product depends on your specific needs and priorities. If price and extensive positive reviews are your primary considerations, Den-Dry is a clear winner. If you prioritize spring support and don't mind the price tag, Froli Star would be the best choice, while those seeking an organic option should consider Coconut Coir.