I don't think they are rated for anything near continuous duty. I have two of the kind with the auto rising vent and remote control. After 2-3 days of continuous use they start to squeak and it is annoying. If I leave them off for a good while, they stop the next time I start them up, but eventually start doing it again.
Something seems to need to be oiled, but I have not started tearing them down to figure out what. going to guess a shot of silicone lube on the motor shaft will help.
John
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