Have a large new house with lots of vinyl clad wood double hung windows on a lake temp today this am is 0 F we have a HRV system house temp is 66 downstairs and 58 upstairs heating with a heat pump and electric furnace indoor humidity is 42 and heat pump runs constantly in these temps house is well insulated in the morning we have water and ice on the bottom edges of all windows this happened last winter with humidity level at 22 do we need to raise the house temp up to 70 or so ? could the HRV system be undersized ? is there any solution ?
Humidifiers - Aprilaire - 600 Humidifier
Answers & Comments
Really not efficent to run a heat pump at those temperatures. Below freezing is not good for the compressor in the outside unit. The humidity in the house with the low temp. is causing the condensation on the windows to freeze. Kinda like an air conditoner does in the summer without the freezing humid air from the house goes over the cold a/c coil and the moisture condensates on the coil running down to drain pan. raising the temp. in the house and lowering the humidity should help. I would also recommend running the electric heat in low outside teperatures.
Running the electric heat should bring the humidity down. Also the humidistat setting should be turned down to 30%-35%..