Energy efficiency rebates in Ohio.

The Humidity Problem Nobody Warned Me About

A building-science consultant who has spent over a decade monitoring electrified homes in Cleveland says humidity control, not heating, turned out to be the hardest problem to solve. Heat pumps kept homes warm even in extreme cold, but on one project — a 1900s house he'd air-sealed and fitted with a right-sized heat pump — indoor humidity crept above 60% despite doing everything building science recommended at the time. The fix ended up costing about $10. He cut a return vent so dry basement air could circulate upstairs, turned on a "reheat" dehumidification setting on the heat pump (which cools the air to wring out moisture, then reheats it so the house doesn't get cold), and turned down the fresh-air ventilator that was bringing in more outdoor moisture than the system could handle. The bigger lesson: sealing up an old house without a moisture barrier under the basement or crawlspace floor can trap humidity that used to escape through the walls and attic. Newer homes with vapor barriers under the slab have less of this problem, but it's not zero. He now argues that a heat pump's ability to dehumidify matters as much as its ability to heat or cool, especially since summer humidity has risen noticeably nationwide since 1950. Homeowners in humid climates, or with older, tighter, or previously damp homes, may want to ask about dehumidification performance and whether a standalone dehumidifier makes sense, not just heating and cooling capacity, when considering a heat pump.