Insulation Savings Calculator

Attic first - heat rises, and most homes have under-insulated attics (current vs IRC target). Walls second, especially in older homes. Basement/crawlspace third. Air sealing should precede or accompany insulation - adding R-value without sealing leaks wastes 30-50% of the benefit. Energy Star recommends R-49 for attics in Zone 5, R-38 in Zone 3.

Attics: blown cellulose (R-3.7/inch, recycled content, easier retrofit) or blown fiberglass (R-2.5/inch, lighter). Walls (existing): dense-pack cellulose or blown fiberglass via small drill holes. Walls (new construction): batt fiberglass or spray foam. Basements/rim joists: closed-cell spray foam (R-6.5/inch, vapor barrier built in). Spray foam costs 2-3x other types but doubles as air seal.

EPA estimates homeowners save an average of 15% on heating/cooling costs by air sealing and adding insulation. On a $2,400/year HVAC bill, that's $360/year. Big-jump retrofits (R-19 to R-49 attic) often save more - 20-30%. Payback varies: 4-8 years for attic top-ups; 15-25 years for wall retrofits; faster if combined with HVAC downsizing.

Section 25C: 30% of materials cost up to $1,200/year for envelope improvements (insulation + air sealing combined). HEAR (Home Efficiency Rebates): up to $4,000 for homes achieving 20-35% energy savings, up to $8,000 for 35%+ savings - capped at 50% of project cost for moderate-income, 80% for low-income. Rollout is state-by-state; check your state energy office for current availability.