When I have wet clothes coming out of the washing machine, I can either tumble-dry them in an electric clothes-dryer, or I can hang them to dry. But I can only hang them in a basement. The basement has poor air circulation and gets kinda cool and humid in the summer. So there is a dehumidifier in the basement, set to cycle on when the humidity gets above 65%. When wet clothes are hanging in the basement, of course the dehumidifier tends to run longer and more frequently.
So there is an electricity usage tradeoff – either the dryer uses a lot of electricity if I tumble-dry, or the dehumidifier uses extra electricity if I hang-dry. Which is likely to be more energy-efficient overall?
Best Answer
The dehumidifier is probably more efficient.
When the wet clothes are drying, there is a latent heat of evaporation that will cool down the basement as the water evaporates. You then have to run the dehumidifier to cause this water to condense again - in the process you will heat the room (as you expel the excess heat). In principle, no heat leaves the building.
If you run the dryer, you expel a lot of hot moist air to the outside world.
Just considering those two closed systems, the dehumidifier should be the better option. Whether it actually is for you depends on other factors: how much running the dehumidifier heat the basement, and where does that heat end up going?