David, Specifically what is your concern regarding heat? The 50watt dehumidifier rods get warm enough to be uncomfortable to touch but not enough to get anywhere near charring wood or bubbling finish. They are not installed against the soundboard but at a distance to heat the air rising to or by the soundboard. I believe the dehumidifier bars should only be installed with the humidity sensing controller. This heat would be damaging if the air was dry. (I've seen those bars attached to the humidifier side of the controller by some piano movers.) I only install smart humidifier bars (mildly warm at 9 watts) so if a customer fails to fill the humidifier tank there is no added heat in/under the piano when humidity is low. Sincerely, Andrew
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