Found out my attic insulation was doing almost nothing after 20 years

I was up there grabbing Christmas decorations and noticed some discolored spots near the soffits. Looked it up and found out that fiberglass insulation loses like 30 percent of its R-value if it gets compressed or wet. Turns out the previous owner just laid batts over the old blown-in stuff without sealing any air leaks. Cost me about $400 to air seal and top it off with new blown cellulose. Has anyone else found their old insulation was basically just decoration?

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avery_fox934mo ago

Pulled out some old insulation in my garage and found a family of mice had been using it as a luxury condo for years. They probably had better heat retention than my actual house did. Lesson learned, I just pretend my attic is an "open air concept" now.

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adam_thomas4mo ago

Luxury condo" killed me haha. I had almost the exact same thing happen in my shed a couple years back. They chewed through a bag of old fiberglass bats and made a nest that looked like a little igloo. I swear they had better insulation than my drafty front door. Now I just tell people my garage is "naturally ventilated" too.

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