Furnace Efficiency Savings Calculator — AFUE Upgrade Cost vs. Savings for Nebraska Gas Prices

Compare your current furnace's Annual Fuel Utilization Efficiency (AFUE) rating against a new high-efficiency model. Enter your Nebraska natural gas usage and upgrade cost to see annual savings, simple payback period, and 10-year net return.

Typical older furnaces: 56–80%. Check your furnace nameplate or manual.
High-efficiency condensing furnaces: 90–98.5% AFUE.
Find on your annual gas bill summary. Nebraska average home: ~700–900 therms/year.
Nebraska average residential rate ~$0.80–$0.90/therm (EIA 2024). Check your bill for exact rate.
Installed cost of new furnace minus any rebates. Nebraska typical range: $2,500–$6,000.
Federal 25C tax credit: up to $600 for ≥97% AFUE. Check Black Hills Energy / OPPD / LES for local rebates.
Typical furnace lifespan: 15–20 years.
Historical Nebraska natural gas price inflation ~2–3%/year (EIA).

Formulas Used

Useful Heat Delivered (therms equivalent):
Useful Heat = Current Annual Therms × (Current AFUE ÷ 100)

New Annual Gas Consumption:
New Therms = Useful Heat ÷ (New AFUE ÷ 100)
               = Current Therms × (Current AFUE ÷ New AFUE)

Annual Therms Saved:
Therms Saved = Current Therms − New Therms

Year 1 Annual Dollar Savings:
SavingsY1 = Therms Saved × Gas Price ($/therm)

Net Upgrade Cost:
Net Cost = Total Upgrade Cost − Rebates & Tax Credits

Simple Payback Period (years):
Payback = Net Cost ÷ SavingsY1

Cumulative Savings with Gas Price Escalation (geometric series):
If escalation rate r > 0:
  Cumulative = SavingsY1 × [ ((1 + r)n − 1) ÷ r ]
If r = 0:
  Cumulative = SavingsY1 × n

Net Return:
Net Return = Cumulative Savings − Net Cost

ROI:
ROI (%) = (Net Return ÷ Net Cost) × 100

Annual CO₂ Reduction:
CO₂ Saved = Therms Saved × 11.7 lbs CO₂/therm

Assumptions & References

  • Nebraska Natural Gas Price: ~$0.80–$0.90/therm residential average (U.S. EIA, 2024 Nebraska data). Verify your exact rate on your monthly gas bill.
  • AFUE Definition: Annual Fuel Utilization Efficiency measures what percentage of fuel energy is converted to usable heat. An 80% AFUE furnace wastes 20% of fuel; a 96% AFUE furnace wastes only 4%.
  • Useful Heat Constant: The model assumes your home's heating load (useful heat required) is the same regardless of furnace efficiency — only the fuel consumed to deliver that heat changes.
  • Gas Price Escalation: Historical Nebraska residential natural gas prices have escalated ~2–3%/year on average (EIA). Future prices are uncertain; adjust accordingly.
  • CO₂ Emission Factor: 11.7 lbs CO₂ per therm of natural gas burned (EPA Greenhouse Gas Equivalencies Calculator).
  • Federal 25C Tax Credit: As of 2023–2032 (Inflation Reduction Act), homeowners may claim up to $600 for qualifying high-efficiency furnaces (≥97% AFUE for gas). Consult a tax professional.
  • Nebraska Utility Rebates: Black Hills Energy, OPPD, LES, and other Nebraska utilities may offer $50–$300 rebates for high-efficiency furnace upgrades. Check your utility's website for current offers.
  • Installation Cost Range: Nebraska installed furnace costs typically range $2,500–$6,000 depending on unit size, brand, and labor market (2024 estimates).
  • Maintenance & Other Costs: This calculator does not account for differences in maintenance costs, duct modifications, or venting changes that may be required for condensing furnaces.
  • Furnace Lifespan: Average gas furnace lifespan is 15–20 years (ENERGY STAR). Choose an analysis period within the expected equipment life.

More Calculators

In the network

Network