I purchased a product dry mesh I few years back for a Previous TC that corrected any condensation under mattress even in hot days with the AC running but could not find a distributor now in the US so I used a 4 x 8 pink 1" foam board from home depot under mattress helps tremendously but venting is really the key. I used reflectix on thermos pane windows and condensation still was an issue without venting with when using campers propane furnace. Hyper vent material I read also works good for rvs and boats but is expensive.