Home energy · EV charging
Does the home charger pay for itself?
Enter your tariff, public charging price, distance and install quote. Every price is yours; nothing is looked up or sent anywhere.
Inputs
The starting values are illustrative, not current market prices. Replace each one with your own bill, quote and fuel receipts.
Payback estimate
Worked example
Using the starting values: 15,000 km a year at 18 kWh/100 km is 2,700 kWh. With 80% charged at home ($0.12/kWh) and 20% public ($0.45/kWh), the EV costs 2,160 × 0.12 + 540 × 0.45 = $502.20 a year. A comparison car using 8 L/100 km at $1.60/L burns 1,200 L, or $1,920. The saving is $1,417.80 a year. The charger and install cost $1,700; charging those 2,160 home kWh at home rather than at the public price saves 2,160 × (0.45 − 0.12) = $712.80 a year, so the charger pays back in about 28.6 months. Set against the whole $1,417.80 saving versus gas, the same $1,700 equals about 14.4 months. These numbers are an example, not a quote.
Formulas and notes
- Energy charged = distance × EV use ÷ 100, split by your home share. Use the wall-side figure (a smart plug, charger app or meter); a battery-side figure understates the bill.
- EV cost = home kWh × home price + public kWh × public price.
- Gas cost = distance × fuel use ÷ 100 × fuel price. In U.S. units, fuel use is converted from mpg and the price from per gallon using 1 mile = 1.609344 km and 1 U.S. gallon = 3.785411784 L (exact definitions).
- Net charger cost = hardware + install − rebates, never below zero.
- Payback months = net charger cost ÷ yearly saving × 12. It shows as not reached when the saving is zero or negative.
Not modelled: financing, taxes, inflation, tariff changes, battery wear, demand charges, and maintenance or insurance differences. Planning estimate only; get an electrician’s quote and check your utility’s EV tariff.
Sources, checked 2026-09-30: U.S. DOE AFDC, Charging at home · FuelEconomy.gov, electric vehicle label (kWh per 100 miles) · NIST SP 811 conversion factors (mile) · NIST SP 811 (U.S. gallon)
FAQ
Is a home EV charger worth it if I can use public chargers?
It depends on the gap between your home tariff and the public price, and on how many kWh you charge at home. The calculator divides the net install cost by the yearly saving from buying those home kWh at your home tariff instead of the public price.
Do I need a Level 2 charger at all?
Not always. The U.S. DOE Alternative Fuels Data Center notes that many EV owners meet daily driving needs with the Level 1 cordset that comes with the vehicle, at no added cost, if a suitable outlet is available. Set hardware and install cost to 0 to see the saving without a Level 2 install.
Which electricity price should I enter?
Your all-in marginal price per kWh: energy plus the delivery or variable charges your bill adds per kWh, and taxes if they apply. Fixed monthly fees do not change with charging. If you are on time-of-use pricing, enter the average price for the hours you charge.
Why are there two payback figures?
Payback against public charging asks whether the charger beats the alternative of plugging in away from home. The other compares the net charger cost to the whole yearly saving versus the comparison car, which is useful if you are weighing the charger as part of switching from gas.
Does this include incentives, financing or tariff changes?
Only what you type in: the rebate field is subtracted from the install cost. Financing, tax treatment, future price changes, battery wear and maintenance differences are not modelled.