Home energy cost calculators
Explore appliance electricity use, solar payback, heat-pump operating cost, or EV charging cost per mile with inputs you can check against your own bill and equipment details.
Calculators
Appliance electricity cost
Estimate annual kWh and cost for up to six appliances from running watts, hours per day, days per year, optional standby use and your own electricity rate.
Solar payback
Model solar production, export credits, upkeep, an inverter replacement and 25-year net value from your own inputs. No federal credit is assumed.
Heat pump vs furnace
Compare annual delivered-heat costs of a heat pump with gas, propane, oil or electric resistance heat using your fuel prices, AFUE and seasonal COP.
EV vs gasoline per mile
Compare gasoline and EV energy cost per mile using annual miles, MPG, home and public charging prices, a maintenance difference and a purchase-price gap.
Featured guides
How to Calculate Appliance Electricity Cost
Convert watts to kWh to dollars, understand nameplate versus actual draw, duty cycles and standby loads, and measure real use with a plug-in watt meter.
Understanding Your Electric Bill and kWh Rates
Break down energy, delivery, fixed charges, taxes, riders and rate structures on an electric bill, and learn to compute your effective and marginal kWh rate.
Is Solar Worth It After the Federal Credit Ended?
See what the IRS says about the Section 25D credit ending, which inputs drive solar economics now and how to test a proposal with PVWatts and utility sources.
Solar Payback Period Explained
Learn the simple solar payback formula and how degradation, rate escalation, self-consumption versus export, upkeep and inverter replacement change the result.
Net Metering and Solar Export Rates: The Basics
Understand how utilities credit exported solar power, from retail-rate net metering to lower avoided-cost or time-varying credits, and find your tariff.
Heat Pump vs Furnace: Comparing Running Costs
Compare heat pump and furnace running costs per delivered MMBtu using Btu conversions, AFUE versus COP, break-even electricity price and cold climate caveats.
Reference pages
How WattWise works
Each calculator uses the values you enter and shows its assumptions beside the result. Electricity prices, export credits, equipment performance and incentive eligibility vary. We are independent and are not affiliated with the agencies named in our sources. No federal credit is included. See About WattWise, the disclaimer and our privacy policy.
Frequently asked questions
What calculators does WattWise offer?
WattWise has four calculators: appliance electricity cost, solar payback, heat pump vs furnace running cost, and EV vs gasoline cost per mile. Each one uses only the numbers you enter.
Are WattWise results quotes or savings promises?
No. Each result is arithmetic on your inputs. Actual bills, equipment performance, utility tariffs and project terms can differ, and the site does not say that any upgrade will save money.
Does WattWise assume any federal energy tax credit?
No. The IRS says the Residential Clean Energy Credit and the Energy Efficient Home Improvement Credit apply to qualifying activity through 2025, and clean vehicle credits apply to vehicles acquired on or before September 30, 2025. Check IRS, state and utility sources for current details.
Where does the example electricity rate come from?
The example is the EIA preliminary U.S. average residential price of about 18.16 cents per kWh for August 2026. Your own rate differs, and prices vary widely by state and utility, so enter the rate from your bill.
Is WattWise a contractor, installer or tax adviser?
No. WattWise is an independent set of calculators and guides for U.S. households. It does not recommend products, installers, brands or financing.