High humidity can be a problem. It’s uncomfortable and it’s a mold risk factor. ASHRAE and ACCA load calculation procedures provide equations to estimate dehumidification loads in residential buildings. But sometimes, it’s instructive to measure the loads in real, occupied houses, rather than just estimating them. The same goes for dehumidification performance of AC units. Measurements from occupied houses and apartments in Europe and the US suggest that both ASHRAE and ACCA load calculations greatly underestimate actual residential dehumidification loads.