Thursday, November 30, 2023


What’s causing a sweating mattress?

By Chris Dougherty
Chris Dougherty is a certified RV technician. Here is a letter he received from a reader while he was serving as’s technical editor.

Dear Chris,
When someone sleeps on the air mattress of our fold-out couch the mattress sweats. We generally have to dry it off each day with a hair dryer before we fold it up. One time we left camp early one morning right after we got up and forgot to open it up when we got home. It was mildewed really bad the next time we went to use it. We have had a 2-inch foam pad with a heavy mattress cover on the bed but it still gets wet. Do you know of anything we can do for this so we don’t have to get a hair dryer out each morning? It happens in warm or cold weather. —Dale R.

Dear Dale,
Thank you for writing in. This is certainly an unusual problem that I personally have not encountered with my unit. Condensation can occur when there is a high humidity level and a significant difference in temperature between an object and the surrounding air.

Moisture can be from any number of sources, not just condensation, so I would eliminate all other sources first, and make sure there is no water in the mattress itself. Be certain there have been no leaks or spills, and that the couch itself is completely dry. Water can be trapped deep in the foam of the mattress and “drain” down to the mattress level when stored. Keep a close eye on humidity levels in the coach, and around, behind and under the couch.

Hope this helps!


Russ and Tiña De Maris
Russ and Tiña De Maris
Russ and Tiña went from childhood tent camping to RVing in the 1980s when the ground got too hard. They've been tutored in the ways of RVing (and RV repair) by a series of rigs, from truck campers, to a fifth-wheel, and several travel trailers. In addition to writing scores of articles on RVing topics, they've also taught college classes for folks new to RVing. They authored the book, RV Boondocking Basics.



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