For what it's worth a dehumidifier rejects more sensible heat than it absorbs. 1st, the moisture removed is latent btu's. These btus used to remove moisture are heat bearing and when rejected, the heat is sensible. Next, the heat of compression and the motor heat are also rejected. For this reason, the condenser is larger than the evaporator. So technically yes a dehumidifier does add a little heat. I don't know if I would consider that a good heat source but it is btu's none the less.