When hot air meets cold air, condensation forms . . . on anything it can. So, any mattress or furniture that has fabric resting on a surface will eventually incur plentitudes of moisture. This almost always forces mold and mildew to occur. If you have something like an RV or you sleep in the basement, this is a constant issue.

You have to solve this to prevent a horrid smell and other health issues from developing. Using a quality underlay will go a long way in helping the issue. HyperVent and Den-Dry are two such products that can help. But which one is better? The answer to this will depend on how much money you want to spend and what kind of effort you want to put into it.

To understand which is better, let’s examine them individually and then do a comparison.


HyperVent is a barrier you can place between your mattress and the frame so that air can flow between, thereby preventing mold and mildew from forming. It’s a polymer material that holds its shape and resists moisture. It’s about ¾ inch thick and the polymer comes in loops. These will not press down over time, allowing for plenty of airflow circulation.

It comes in a roll, so you can cut it with scissors to fit your mattress. Plus it’s washable and you can use water on it to clean it if necessary. The water won’t destroy the material and it will keep for years to come. It’s lightweight, inexpensive and very ideal. It costs about $12.50 per linear foot and you order it via phone call.


  • ¾ inch thick with strong polymer loops that won’t compress.
  • Talking to a real human being is far better than dealing with an AI algorithm. 
  • It’s inexpensive and you can purchase per linear foot.


  • You have to cut it to the size you want (which could be a pro depending on your preferences).
  • You can only order this by calling their store directly.


The other option for mold prevention is Den-Dry. This highly engineered underlay comprises recycled materials. It has a grid mounted over spun polyethylene. Not only will this be excellent for keeping surfaces dry, it won’t crush down. This means it will last for years without needing to replace it.

It sits about an inch above the surface between things like fabric and mattresses. Den-Dry’s design allows for better mildew control because of the plentitudes of airflow and porousness of the fabric. What’s more, they offer a variety of sizes specifically for mattresses such as twin, queen and king. You can cut it down for things like seats or trunks.


  • You can purchase it through their website, via phone call or on Amazon.
  • It provides more confidence and control with its thickness of one inch.
  • Convenient mattress sizes means you don’t have to cut it down yourself.


  • It’s very expensive, ranging between $99 for a twin and up to $170 for a king.
  • Sizes tend to be too small for regular-sized mattresses.

Which Is Better: HyperVent vs Den-Dry?

As you can see, both HyperVent and Den-Dry have some great advantages but they also have some serious disadvantages. If you’re looking for something quick and hassle-free for your RV mattress, then Den-Dry is the way to go. However, it’s rather costly but the quality is worth the extra money.

Alternatively, if you’re on a budget and looking to cut it down to a precise size yourself, then opt for HyperVent. But expect for a more time-consuming purchasing process than for Den-Dry. The downside with HyperVent is that it isn’t as accessible as Den-Dry.

Both Are Great!

Either of these airflow control materials will be ideal for camping trips, basement beds, futons, RV mattresses and so much more. They’ll help reduce the moisture that can occur as a result of heat mixing with cold air. These fabric underlays won’t breakdown quickly and you can use them almost anywhere.

But, Den-Dry (see Amazon) seems much sturdier and provides more distance between the fabric and the surface it sits on. It’s grate design and one-inch height is ideal for almost any situation. Plus, all Den-Dry models are black so they will blend in with decor and not present an eye sore.


Mattress mold and mildew is nothing anyone wants to deal with. Mold and mildew can present serious illnesses along with a horrid and atrocious smell. The odor can overpower a small space like an RV, making it unpleasant to say the least.

Whether you go with HyperVent or Den-Dry, either will be an excellent choice for helping to mitigate this problem. The one that will be best will come down to what you can afford and how quickly you need to install it.

See Also:
BioBidet USPA 6800 Vs. TOTO C200 – Which Brand Is Best?
Can You Install TOTO WASHLET On Any Toilet?
6 Best Hot Tubs For Back Pain
Can You Put A Futon Mattress On A Bed Frame?

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