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Large screens use three columns, smaller screens use two, and mobile uses one.
Example data table
| Upgrade type | Typical cost range | Common savings range | Notes |
|---|---|---|---|
| Attic insulation | $1,200–$3,500 | 8%–18% | Often a strong first step in many climates. |
| Air sealing | $300–$1,500 | 5%–15% | Targets leaks around ducts, attic hatches, and rim joists. |
| Windows and doors | $3,000–$15,000 | 5%–12% | Savings vary with existing condition and glass type. |
| Weatherstripping | $50–$400 | 1%–4% | Low cost, best for drafts and comfort improvements. |
These are illustrative examples only. Your results depend on climate, equipment, and workmanship.
Formula used
- Baseline cost (usage method):
Cost = kWh × rate + therms × rate - Combined savings rate:
R = 1 − Π(1 − rᵢ)whererᵢare upgrade savings rates. - Year 1 savings:
S₁ = Baseline × R - Savings over time:
Sₜ = S₁ × (1+g)^(t−1) × (1−d)^(t−1) - Net cash flow:
CFₜ = Sₜ + Maintenance + Credit + Residual − Loan - Present value:
PVₜ = CFₜ / (1+k)^tandNPV = −Upfront + Σ PVₜ - Payback: first year where cumulative cash flow becomes non‑negative.
IRR is estimated by finding the discount rate that makes NPV equal to zero.
How to use this calculator
- Choose your baseline method: direct annual cost or usage and rates.
- Enter upgrade costs and realistic savings percentages for each measure.
- Add rebates and tax credits, and set when the credit is received.
- Select analysis years, energy price growth, and a discount rate.
- Optionally enable financing to include loan payments and interest.
- Click Calculate savings to view results above the form.
- Download your results as CSV or PDF for recordkeeping.
Planning note: For best accuracy, use an energy audit or past billing data to calibrate baseline costs and savings rates.
This tool provides estimates, not professional advice.