Advice on passive air inlets with bath fan exhaust ventilation?
Background: new construction, climate zone 6 (03846), 12" double stud walls w cellulose, heating/cooling is single Mitsubishi 12k btu heat pump, 2 story, very open floor plan downstairs (and up). Blower door test done before insulation/sheetrock and came in at 0.67 ACH at 50 Pascal.
Our ventilation strategy is Panasonic WhisperGreen bath fans (80 cfm models), one in our downstairs half bath and one in upstairs full bath, short and mostly straight ducting to exterior. Before insulation and sheetrock, we installed two Panasonic passive air inlets (they allow up to 18cfm each), one in upstairs master bedroom and one in open downstairs area. We stayed at two because we thought that might be enough and didn't want to put more holes in the envelope at that time.
I would imagine windows will be closed much of the time in winter, but open a decent amount spring through fall. Some south 2nd story windows could be cracked in winter because they are sheltered and stay warmer in sun.
Any advice especially from those that have used this system...are we not providing enough make up air for the bath fans and hampering their ability to exhaust, especially shower moisture? Maybe another air inlet in the other bedroom upstairs?
Not crazy about more holes in the wall, but I don't want to mess up the ventilation strategy. Thanks,
Posted Jul 3, 2014 11:27 AM ET
Edited Jul 4, 2014 5:30 AM ET
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