If the heat produced by the dehumidifier (and they make a fair amount, they are little aircon units) doesn't tip the room over 85 avg 90 max, it'd be a solution for a ventless grow. I rely on my dehumidifier to warm up my op in winter during lights off as well as keep RH under control.
Walmart has a cute little a/c unit that sits entirely in the room with a small exhaust vent to outside for the excess heat. Naturally, with the cooling coils inside, it's a dehumidifier too.