The savings calculator is an arithmetic decision aid. It uses only the household, utility, and cost values you enter. It supplies no product specification, electricity rate, price, rebate, warranty, equipment life, or savings assumption.
Inputs you provide
- Your current annual water-heating cost
- Your independently obtained HPWH annual electricity estimate in kilowatt-hours
- Your electricity rate
- Your incremental upfront cost compared with the alternative you are considering
- Your analysis period in whole years
Calculations
- HPWH annual cost = annual kWh × electricity rate
- First-year savings = current annual cost − HPWH annual cost
- Simple payback = incremental upfront cost ÷ positive first-year savings
- Cumulative nominal savings = first-year savings × analysis years
- Net savings after incremental upfront cost = cumulative nominal savings − incremental upfront cost
A zero or negative first-year saving has no simple-payback value.
Limitations
Results are arithmetic illustrations, not predictions or guarantees. The calculator does not model rate changes, inflation, financing, maintenance, repairs, replacement, taxes, installation differences, household changes, time value of money, or equipment life.
Verified methodology sources
The U.S. Department of Energy methodology source supports the simple-payback ratio and notes that actual HPWH performance varies with use and operating conditions. The Federal Trade Commission consumer guidance explains that annual operating cost is an estimate and actual cost depends on appliance use and local energy price. Neither source supplies values to this calculator.
Use the savings calculator with values you obtained independently.