House is under negative pressure. Why?
I think my house is under negative pressure. There’s always a lot of dirt that builds up on the bottom flat horizontal part of my double-hung windows (this would be the surface that the bottom of the lower sash meets when you close the window). Technically it’s still the exterior.
All windows experience this dirt buildup. I cleaned them all thinking that it’s never been done in 50 years, but 1 month later they’re all dirty again. If I wiped the surface with a wet rag, the rag pretty much has mud on it. It’s not dust, it’s more like soil. Windows are closed year-round.
Is this a testament of negative pressure? The house has been air sealed to death, or are we just using our bathroom fan / microwave fan too much?
We have respiratory issues that started when we moved in & we know that the previous occupants died from lung cancer. We know something is wrong with the air in the house but can’t figure it out.
House: single story, double-wythe brick, basement, 1960s
– Walls: brick, 1″ paper-faced fiberglass, drywall
– Attic: loose fill fiberglass + cellulose, R60
– Basement walls: concrete, R11 unfaced fiberglass, plastic, drywall
– clothes dryer, vented to outside
– furnace, high efficiency, PVC for intake & exhaust
– water heater, PVC for intake & exhaust
– bathroom fan, 70cfm, exhausts through roof
– microwave fan, 150?cfm, exhausts through roof
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