Attic First, Then Walls
In Green Bay's heating-dominated climate, the attic is where you lose the most BTUs. Boosting from original R-11 to R-49 in the attic alone can cut heating bills by 15–25% per year. Many older homes also have uninsulated rim joists (where the floor meets the foundation wall) — a 2-hour DIY fix that eliminates significant cold-air infiltration.
Signs You Need an Insulation Upgrade
- Visible daylight or frost at the attic hatch edges in winter
- Pipes in exterior walls freezing during cold snaps
- Ice dams forming on the roof edge each winter
- Heating bills that spike more than 30% in January–February
- Cold floors on the first floor (uninsulated crawl or basement)
DIY Opportunities
Rim joist insulation with cut-and-cobble foam board is a classic weekend DIY project. Attic blowing is DIY-friendly with a rented machine. Air-sealing the attic (caulking around penetrations before adding insulation) is the most important step — insulation without air-sealing is like putting on a sweater with holes in it.
Cost in Green Bay
Attic upgrade: $2,000–$7,500 installed. Air sealing adds $500–$1,500 but is worth it. Check for Minnesota, Wisconsin, or state utility rebates — most northern utilities offer $0.10–$0.30 per square foot for attic insulation improvements.