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Insulation Upgrade Payback Calculator
Attic insulation upgrade is consistently the highest-ROI residential energy retrofit. Going from R-13 to R-49 typically captures 60-75% of available ceiling-loss reduction, and combined with IRA tax credits and utility rebates, payback often falls under 5 years. This calculator builds the cost and savings model so owners can prioritize insulation against window, HVAC, and solar alternatives.
Blown cellulose $1-2; spray foam $3-7
Net cost (after incentives)
$2,100
Payback (yrs)
6
Annual savings
$353
25-year savings
$8,816
How the math works
Attic insulation (R-13 → R-49) typically pays back 5-10 years and is one of the highest-ROI energy retrofits. Wall insulation harder/costlier; basement rim joist sealing high-impact and low cost.
25C credit covers 30% up to $1,200/yr for insulation. Combine with utility prescriptive rebates ($0.20-$0.50/SF) for further reduction.
How to Use
- Enter attic SF and per-SF cost (cellulose $1-2; spray foam $3-7).
- Enter current and new R-values.
- Enter annual HVAC cost and incentives.
- Read net cost, payback, annual and 25-year savings.
Frequently Asked Questions
Best material?
Blown cellulose: cheapest ($1.00-1.50/SF) and 80% recycled. Fiberglass batts $0.80-1.20/SF. Spray foam (closed cell) $3-7/SF — best air sealing but pricey.
Where to add insulation first?
Order: 1) air sealing (caulk, foam top plates); 2) attic; 3) rim joists; 4) walls (only if open). Walls are expensive to retrofit unless during full gut renovation.
DIY?
Blown cellulose can be DIY rental ($150-250 day rental, equipment included). Spray foam requires professional crew.
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