Will bath fan exhaust adequately ventilate a tight house?
We built a pgh in Virginia (Zone 4) and got unexpectedly good results on the blower-door test: 0.5 [email protected] For ventilation, we have a Panasonic WhisperComfort ERV (40 CFM, balanced) and two Panasonic Whispergreen bath fans (30 – 80 CFM each, exhaust only). The house is 3160 ft2, 42,500 ft3.
We are de-bugging the ventilation system and I am seeing CO2 levels consistently above 2000, with only two occupants at present. (I also had septic odors drawn in from unused laundry traps, but that problem is solvable.)
I suspect that the house is too tight for my exhaust-based ventilation strategy to work. This is a problem of luxury! But it is a problem.
I would really like to achieve CO2 levels lower than 2000 ppm! I have a spare (sealed) 6″ make-up air duct that I could open, but that seems pretty crude. Or I could install some retrofitted Lunos fans, or perhaps I could retrofit a second ERV. But those ideas are kind of expensive.
Has anyone had any experience with a house that is too tight for their ventilation strategy?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part