Does it show you the percentage of humidity in the air? If not, the one I bought had a thermometer and humidity gauge that I picked up for I think $8.00 at Walmart. It was portable and could stand alone or stick to metal with a magnetic backing.

This could help cut out some of the guesswork and all. :-)

We have had several customers come to us to buy our RugBuddy heaters to simply go under a bathroom rug in similar situations. The only problem is trying having an outlet that is easily accessible for the plug.

No matter which one you choose, make sure that it is GFCI protected if it's going to be used anywhere near water!