Estimate your annual energy savings, payback period and 20-year ROI from upgrading your home insulation. Free, instant, no sign-up.
Heated/cooled floor space (not garage or basement)
Auto-fills Heating Degree Days below
R-11 walls / R-19 attic are common existing values
DOE recommends R-38–60 for attics; R-21 for walls
US average ~$0.16/kWh. For gas: 1 therm = 29.3 kWh
Auto-set by climate zone; adjust for your city
Total installed cost (materials + labor). Get 3 quotes. IRA 30% tax credit may apply.
R-value (thermal resistance) measures how well a material resists heat flow. The higher the R-value, the less heat passes through — and the less energy your furnace or air conditioner must use to maintain comfortable indoor temperatures.
Heat loss through an insulated assembly follows a simple formula: heat loss is inversely proportional to R-value. Doubling R-value from R-11 to R-22 halves heat loss through that assembly. Going from R-11 to R-38 reduces it by 71%. This is why upgrading under-insulated homes delivers such dramatic returns.
| Location | Attic | Exterior Wall | Floor/Crawl Space |
|---|---|---|---|
| Zone 1–2 (Hot: FL, AZ) | R-30 to R-49 | R-13 to R-15 | R-13 |
| Zone 3 (Warm: GA, TX) | R-38 to R-49 | R-13 to R-15 | R-19 to R-25 |
| Zone 4 (Mixed: VA, OR) | R-38 to R-60 | R-13 to R-21 | R-25 to R-30 |
| Zone 5–6 (Cold: IL, CO) | R-49 to R-60 | R-15 to R-21 | R-25 to R-30 |
| Zone 7–8 (Very Cold: MN, AK) | R-49 to R-60 | R-21 | R-30 to R-38 |
| Type | R-Value/inch | Best For | Cost Installed |
|---|---|---|---|
| Blown-in cellulose | R-3.2–3.8 | Attics, walls (drill & fill) | $0.50–$1.50/sq ft |
| Blown-in fiberglass | R-2.5–3.7 | Attics, cathedral ceilings | $0.50–$1.25/sq ft |
| Fiberglass batts | R-3.1–4.3 | Open walls, floors, DIY | $0.40–$1.00/sq ft |
| Mineral wool batts | R-3.0–4.2 | Walls, fire resistance | $1.00–$2.00/sq ft |
| Open-cell spray foam | R-3.7–3.9 | Rim joists, tight spaces | $1.50–$3.00/sq ft |
| Closed-cell spray foam | R-6.0–6.5 | Basement walls, crawl spaces | $3.00–$8.00/sq ft |
| Rigid foam board (EPS) | R-3.6–4.2 | Exterior sheathing, slabs | $1.50–$3.50/sq ft |
| City | HDD/year | Climate Zone |
|---|---|---|
| Miami, FL | 200 | Zone 1 (Hot) |
| Phoenix, AZ | 1,350 | Zone 2 (Hot) |
| Atlanta, GA | 3,000 | Zone 3 (Warm) |
| Dallas, TX | 2,300 | Zone 3 (Warm) |
| Washington, DC | 4,200 | Zone 4 (Mixed) |
| Seattle, WA | 4,800 | Zone 4 (Mixed) |
| Chicago, IL | 6,500 | Zone 5 (Cold) |
| Denver, CO | 6,000 | Zone 5 (Cold) |
| Boston, MA | 5,600 | Zone 5 (Cold) |
| Minneapolis, MN | 8,000 | Zone 7 (Very Cold) |
| Anchorage, AK | 10,800 | Zone 7 (Very Cold) |
R-value (thermal resistance) measures how well insulation resists heat flow. Higher R-values mean less heat escapes in winter or enters in summer. DOE recommends R-38 to R-60 for attics and R-13 to R-21 for walls, depending on climate zone. Doubling R-value roughly halves heat loss through that assembly, so upgrades from R-11 to R-38 are especially impactful.
The DOE estimates that properly insulating and air sealing saves the average homeowner 15% on total energy bills — typically $200–$800/year. Homes in cold climates with poor existing insulation see the largest returns. A 1,500 sq ft home upgrading from R-11 to R-38 in Chicago can save $300–$500/year.
Attic insulation typically pays back in 3–5 years. Wall insulation takes 6–15 years due to higher installation cost. After payback, all savings continue for the life of the building (40+ years), making insulation one of the best-return home improvements available.
HDD measure climate severity for heating. Each day contributes HDD = max(0, 65°F − average temperature). Minneapolis has ~8,000 HDD; Atlanta ~3,000; Miami ~200. Higher HDD = more heating energy needed = greater insulation savings.
Yes. The Inflation Reduction Act (IRA) provides a 30% federal tax credit (up to $1,200/year) for qualifying insulation and air sealing materials installed in your primary residence through 2032. This significantly reduces net cost and shortens payback. See IRS Form 5695.
The attic gives the best ROI: heat rises, attic losses are large, and blown-in insulation is cheap ($0.50–$1.50/sq ft). Next are crawl spaces and rim joists, then exterior walls. Air sealing (caulk, weatherstripping) often has the fastest payback — sometimes under 1 year.
Blown-in (cellulose/fiberglass): R-3.2–3.8/inch, great for attics, low cost. Fiberglass batts: R-3.1–4.3/inch, common in walls, DIY-friendly. Spray foam: R-3.7–6.5/inch, seals air gaps, expensive ($3–$8/sq ft). Rigid foam board: R-4–6.5/inch, used for exterior walls and slabs.
Insulation blocks solar heat gain from the attic (140°F+) from radiating into living spaces. A well-insulated attic at R-49 can reduce attic heat flux by 70% vs R-11, directly cutting AC load. DOE estimates insulation reduces cooling costs 10–25% in hot climates, potentially over $200/year in Sun Belt states.