Dumber than a dehumidifier that uses lots of electrical energy?
It sucks up basement air from near the floor and exhausts it from the house when the basement air exceeds, say, 60% RH.
If the house is air-conditioned.
Yes.
Sure, if the house is being heated or air-conditioned.
Does the Humidex add more than 5 cents/pint to AC and heating bills? That depends on the weather. Moving basement air upstairs would use less energy in a house with AC. A dehumidifier would use more, since it adds to the AC load.
A little extra ventilation as needed isn't so bad in wintertime. Moving cold air in from a basement window seems better than moving warm air down from upstairs. It might come in through a concentric duct inside the exhaust duct. Moving basement air out through an air heater on a south wall and back to the basement after condensation (with an airflow high enough to avoid freezing) could use less energy than ventilation.
My newish Kenmore dehumidifier acts like a heat pump with a 1.6 COP, ie for every kWh of electricity consumed it condenses 2.047 pounds of water, which makes 0.6 kWh (2047 Btu) of sensible heat. Condensing a pound of vapor requires 1/2.047 = 0.4885 kWh worth 4.9 cents at 10 cents/kWh. If
1 kWh consumed offsets 1.6 kWh of electric resistance heat in winter, the net energy profit for removing a pound of water vapor with a dehumidifier is 0.6/2 = 0.3 kWh. If the house has a heat pump or gas or oil heat, the "profit" is likely a net loss.NREL says the outdoor humidity ratio wo = 0.0025 pounds of water per pound of dry air on an average 30 F January day near Phila. Indoor air at 70 F and 60% RH has wi = 0.009476, so removing a pound of water by ventilation requires moving 1/(wi-wo) = 143 pounds of fresh air through the house. Warming it from 30 to 70 F requires 0.24x143(70-30) = 1376 Btu, ie 0.4 kWh. A 2470 cfm 90 W fan can move 143 pounds in 143/(2470x0.075) = 0.77 minutes, consuming 90x0.77/60 = 0.001 Wh. So winter ventilation uses less electricity than the dehumidifier, but there's no desirable heat pump effect.
Mold seems unlikely to me, if the AC works and the Humidex shuts off when the basement RH drops to 60%.
Maybe, in wintertime. But most houses don't need dehumidification then.
That's a concern, in a house without AC. I can picture the Humidex pumping humid outdoor air into a basement with a cold slab that keeps condensing water out of the air until the slab warms to the dewpoint, when condensation would stop, but that might take a long time and make a big pool of water which doesn't disappear until winter. IMO, these things could use better controls, at least, and more competition, in light of their price.
Nick
Herbach and Rademan (800) 848-8001