Home Charging Station ROI Calculator
Estimate your payback period and lifetime savings from installing a Level 2 home EV charging station compared to public charging.
Formulas Used
Annual kWh:
Annual kWh = Annual Miles ÷ EV Efficiency (mi/kWh)
Annual Charging Cost (any scenario):
Cost = Annual kWh × [(%Home × Home Rate) + (%Public × Public Rate)]
where %Public = 1 − %Home
Annual Savings (Year y):
Savingsy = CostBefore,y − CostAfter,y
Rates inflate each year: Ratey = Rate1 × (1 + Inflation%)y−1
Net Installation Cost:
Net Cost = Installation Cost − Federal Credit − Rebates
Payback Period:
Fractional year when Cumulative Savings ≥ Net Installation Cost
Payback = (y−1) + (Net Cost − Cumulativey−1) ÷ Savingsy
Lifetime Net Benefit:
Net Benefit = Σ Savingsy (y=1…N) − Net Installation Cost
ROI:
ROI = (Lifetime Net Benefit ÷ Net Installation Cost) × 100%
Assumptions & References
- Level 2 EVSE (240V, 32–48A) equipment cost: $400–$900; electrician installation: $300–$1,000 (HomeAdvisor 2024).
- Federal Alternative Fuel Vehicle Refueling Property Credit (IRA 2022, 26 U.S.C. §30C): 30% of cost, up to $1,000 for residential installations.
- U.S. average residential electricity rate: ~$0.16/kWh (EIA, 2024).
- Public DC fast charging average: $0.35–$0.50/kWh; Level 2 public: $0.25–$0.40/kWh (PlugShare, ChargePoint 2024).
- Typical EV efficiency: 2.5–4.5 mi/kWh depending on vehicle and conditions (EPA fueleconomy.gov).
- Historical U.S. electricity price inflation: ~2–3%/year (EIA).
- Level 2 EVSE lifespan: 10–15 years under normal residential use.
- Model assumes charging behavior shifts immediately upon installation.
- Does not include potential home resale value increase (~$5,000–$10,000 per Zillow/NAR studies) or time savings vs. public charging.
- Consult a licensed electrician and your utility for actual installation costs and time-of-use (TOU) rate opportunities.