How Home vs Public Charging Comparator Works?
This tool works by subtracting the yearly cost of home charging from the yearly cost of public fast charging. The result is the yearly premium paid for public charging.
Price home charging
Calculate yearly cost at the home rate. The default is 3,500 kilowatt-hours (kWh) at $0.15 per kWh: $525.
Price public charging
Calculate yearly cost at the public rate. The default is 3,500 kWh at $0.45 per kWh on direct current (DC) fast chargers: $1,575.
Enter both yearly costs
Type the home charging total and the public charging total.
Read the public premium
The tool shows the extra yearly cost of charging in public.
Home vs Public Charging Comparator Formula
The formula is Public Premium = Public Charging Cost − Home Charging Cost.
Public Premium = |Public Charging Cost − Home Charging Cost|Formula variables
- Home Charging Cost
- Yearly kWh × home rate per kWh.
- Public Charging Cost
- Yearly kWh × public rate per kWh.
Worked example
- Home Rate ($0.15/kWh): $525.00/yr
- DC Fast Public ($0.45/kWh): $1,575.00/yr
- Home: 3,500 kWh × $0.15 = $525.
- Public: 3,500 kWh × $0.45 = $1,575.
- Premium: $1,575 − $525 = $1,050.00 per year.
Result: $1,050.00 ($/year premium)
3,500 kWh per year covers about 12,250 miles (19,715 km) in an EV that averages 3.5 miles per kWh. Public DC fast charging costs 2 to 4 times the home rate.
Home vs Public Charging Comparator Conversion Table
The table shows the yearly public charging premium for 3 home costs against 3 public costs.
Rows: Home Rate ($0.15/kWh) ($/yr). Columns: DC Fast Public ($0.45/kWh) ($/yr). Cells: $/year premium.
| $/yr | $1,000.00/yr | $1,575.00/yr | $2,100.00/yr |
|---|---|---|---|
| $400.00/yr | $600.00 | $1,175.00 | $1,700.00 |
| $525.00/yr | $475.00 | $1,050.00 | $1,575.00 |
| $700.00/yr | $300.00 | $875.00 | $1,400.00 |
Charging only in public at $2,100 per year costs $1,700.00 more than charging at home for $400.
What is Home vs Public Charging Comparator?
The Home vs Public Charging Comparator is a tool that measures how much more an electric vehicle (EV) owner pays by charging at public stations instead of at home. The tool shows the value of home charging access.
Level 2 home chargers use residential electricity rates. Public DC fast chargers charge commercial rates plus network fees, often $0.35 to $0.60 per kWh.
The comparator helps renters, apartment dwellers, and frequent travelers see the cost of depending on public charging.
What are the uses of Home vs Public Charging Comparator?
There are 4 main uses of the Home vs Public Charging Comparator: deciding on a home charger install, comparing apartments with charging, budgeting road trip charging, and checking workplace charging value.
Deciding on a home charger install
Owners compare a $1,000 to $2,000 install with the yearly saving.
Comparing apartments with charging
Renters value units that include charging access.
Budgeting road trip charging
Drivers price DC fast charging on long trips.
Checking workplace charging value
Employees value free or cheap workplace charging.
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