Home Charger ROI Calculator

Is investing in a home charger worth it? Find out your payback period.

What this calculator does

Estimate the payback period for installing a home EV charger by comparing home charging costs to public charging costs. The tool calculates monthly savings, estimated payback time, and net savings after one and five years.

Inputs explained

Installation cost: Total upfront cost for charger and installation.
Monthly kWh: Energy you typically charge each month.
Home rate: Electricity price per kWh at home.
Public rate: Average price per kWh at public stations.

How it works / Method

Compute monthly charging cost at home and at public stations.
Subtract to find monthly savings from home charging.
Divide installation cost by monthly savings to estimate payback time.
Compute net savings after one and five years.

Formula(s) used

monthly_home = monthly_kWh * home_rate

monthly_public = monthly_kWh * public_rate

monthly_savings = monthly_public - monthly_home

payback_months = install_cost / monthly_savings

net_1yr = (monthly_savings * 12) - install_cost

net_5yr = (monthly_savings * 60) - install_cost

Units: costs in currency, energy in kWh. Assumes constant rates.

Inputs

Currency

Total Installation Cost

Include charger unit, electrician, and permits.

Monthly Energy Needs

kWh

Approx 300 kWh = 1000 miles (at 3.3 mi/kWh).

Home Rate

$ /kWh

Public Rate

$ /kWh

ROI Analysis

Monthly Savings -

Payback Period -

1-Year Net Savings -

5-Year Net Savings -

Step-by-step example

Example inputs: $1,200 installation, 300 kWh per month, home rate $0.15/kWh, public rate $0.35/kWh.

Monthly home cost: 300 * $0.15 = $45.
Monthly public cost: 300 * $0.35 = $105.
Monthly savings: $105 - $45 = $60.
Payback: $1,200 / $60 = 20 months (about 1.7 years).
Net after 1 year: $60 * 12 - $1,200 = -$480.
Net after 5 years: $60 * 60 - $1,200 = $2,400.

Use cases

Decide if a Level 2 home charger pays back for your driving.
Compare installer quotes by changing the installation cost.
Estimate savings if you switch from public to home charging.
Evaluate the impact of off-peak electricity rates.
Plan for rebates by lowering the installation cost input.
Compare payback for different EVs with different kWh use.

Assumptions & limitations

Rates are assumed constant and do not model time of use shifts.
Charging losses, maintenance, and repairs are not included.
No financing costs, interest, or time value of money are included.
Public pricing can vary by station or time; use a blended rate.
Monthly kWh is assumed stable throughout the year.
Results are estimates for planning, not a guarantee.

Disclaimer: Results are estimates for planning only. Real world savings depend on pricing, charging behavior, and incentives.

Frequently Asked Questions

Does this include rebates or tax credits?

No. Enter your net installation cost after any rebates or incentives. If you are unsure about the rebate amount, run the calculator twice: once with the full cost and once with the expected rebate applied. This shows a realistic range for payback and helps you decide how much the incentive changes the outcome.

What if public charging is cheaper than home?

If the public rate is lower than your home rate, monthly savings can be zero or negative and the payback period may show as never. This can happen in areas with low off-peak public pricing or high residential rates. In that case, a home charger still provides convenience but may not pay back financially. Adjust the rates to reflect your actual mix of charging.

Should I use off-peak rates?

If you charge mostly overnight, using your off-peak rate will provide a more accurate estimate. If you charge at different times, use a blended average. Many utilities list separate energy charges by time of day, so review your bill or rate plan to estimate the effective home rate for your charging schedule.

How do I estimate monthly kWh?

Multiply your monthly miles by kWh per mile from your vehicle, then add a small buffer for charging losses if needed. For example, 1,000 miles at 0.30 kWh/mi uses about 300 kWh. If you already track charging sessions, add the kWh totals from your charging app or utility records for the most accurate monthly value.

Does this include financing or time value of money?

No. The payback calculation is a simple ratio of upfront cost to monthly savings. It does not include interest, financing terms, or discount rates. If you financed the installation, your effective payback could be longer. You can approximate this by increasing the installation cost to reflect interest or by calculating a separate finance schedule.

Can I use this for workplace charging?

Yes. Treat the workplace rate as the public rate and compare it to your home rate. If workplace charging is free, enter zero for the public rate and the calculator will show the opportunity cost of installing a charger at home. This can help you decide whether convenience is worth the expense.

Sources & references

U.S. Energy Information Administration: Measuring electricity - Defines kWh for cost calculations.
DOE Alternative Fuels Data Center: EV charging options for consumers - Describes home and public charging contexts.
U.S. EPA: Plug-in electric vehicle charging basics - General guidance on EV charging behavior.
Schema.org: FAQPage, WebPage, and BreadcrumbList - Structured data definitions used on this page.