HVAC System Payback Period Calculator — Upfront Cost vs. Long-Term Savings
Enter your current system's efficiency, the new system's efficiency, your energy costs, and installation details to find out exactly when your investment breaks even — and how much you'll save over time.
Formulas Used
Net Upfront Investment:
Net Cost = New System Cost − Rebates & Tax Credits
Efficiency Improvement Ratio:
Efficiency Ratio = Old SEER (or HSPF/AFUE) ÷ New SEER (or HSPF/AFUE)
Year-1 Annual Energy Savings:
Energy Savings (Yr 1) = Current Annual Energy Bill × (1 − Efficiency Ratio)
Year-1 Maintenance Savings:
Maintenance Savings (Yr 1) = Old Annual Maintenance Cost − New Annual Maintenance Cost
Total Savings in Year n (with energy inflation):
Total Savings (Yr n) = Energy Savings (Yr 1) × (1 + Inflation Rate)^(n−1) + Maintenance Savings (Yr 1)
Cumulative Savings after N years:
Cumulative Savings = Σ [Total Savings (Yr n)] for n = 1 to N
Simple Payback Period (no inflation):
Simple Payback = Net Cost ÷ Year-1 Total Savings
Inflation-Adjusted Payback: The year in which Cumulative Savings first equals or exceeds Net Cost, with linear interpolation within that year.
ROI in Year n:
ROI = (Cumulative Savings − Net Cost) ÷ Net Cost × 100%