Energy Savings Estimator
Estimate annual energy consumption, cost savings, and CO₂ reduction when upgrading to a more efficient appliance or system.
Formulas Used
Annual Energy (kWh/yr)
E = P × H × D ÷ 1,000
P = power draw (W), H = daily hours, D = days/year
Annual Cost ($)
Cost = E × Rate
Annual Savings
ΔE = Eold − Enew |
ΔCost = ΔE × Rate
CO₂ Reduction (kg/yr)
CO₂ = ΔE × 0.386 kg/kWh
Efficiency Improvement (%)
η = (Pold − Pnew) ÷ Pold × 100
Assumptions & References
- CO₂ emission factor of 0.386 kg CO₂/kWh is the U.S. EPA national average grid emissions factor (EPA eGRID 2023).
- Electricity rate varies by region; the U.S. average residential rate is approximately $0.13/kWh (EIA, 2024).
- Savings are calculated assuming constant usage patterns throughout the year.
- No standby/idle power draw is included; enter total average draw if applicable.
- Payback period requires the cost difference of the new device, which is not included here.
- Formula reference: ENERGY STAR® Energy Savings Calculator Methodology, U.S. DOE.