I’d like to increase the humidity levels in my old stone and brick house (~120 years) during the winter. Right now it’s about mid-20% and I’d like it to be 30% to 35%.
This house came with a HRV system system that I understand brings outdoor air into the house. Considering that it’s usually more than 50% RH outside, I am curious why running the system seems to dehumidify the house and make my problem worse rather than improve things. I understand that the water-carrying capacity of cold air is less than warm air, so why would bringing in 50% RH cold air into a warm space of 20% RH not increase the indoor RH? Is there something else possibly wrong that I should investigate?
Bonus details for those curious:
The house came with an evaporative flow-through bypass humidifier that pours about $25 to $60 of water down the drain each month while also not affecting the humidity. My current working strategy is run a large console humidifier next to a large return near the furnace – with this setup I can crank the house up to 40% RH easily but it requires filling up the water tanks every day or so, which isn’t sustainable while I’m away. Coming up with a better way using the HRV would be neat.