EV Home Charger Payback Calculator NZ
This calculator works out how long it takes a home EV charger to pay for itself in New Zealand, comparing what you would spend charging without one against the cheaper off-peak power you can use once it is installed. A dedicated home charger typically costs more upfront than plugging into a standard household socket, but it charges faster and lets you shift your charging to off-peak electricity rates, avoiding the higher cost of public fast chargers or daytime power. You enter the charger install cost, how far you drive each year, your car's energy use in kWh per 100km, and the saving per kWh you expect from charging at home instead of elsewhere. From these figures the calculator works out the kWh you charge each year, your saving per year, and the payback period, showing how many years it takes for the saving to cover the install cost. Heavy drivers on a good off-peak plan tend to pay the charger off fastest, while those who drive short distances may find a standard plug is enough. Use it to check whether the upfront cost stacks up for your driving pattern before you commit, and remember that faster, more convenient charging is a real benefit even where the numbers are marginal. This is an indicative estimate only, since actual power prices, driving distance and charger costs vary.
The "saving per kWh" is the gap between your charging cost without the charger (often public fast charging or peak home rates) and with it (off-peak home charging). Faster, more convenient charging is a benefit beyond the dollars. Estimate only.
How it works
The calculator works out the energy you charge each year from your distance and your car's consumption, multiplies it by the saving per kWh the home charger gives you, and divides the install cost by that yearly saving to get the payback period. Heavy drivers and a big off-peak saving pay the charger off fastest; light drivers may find the standard plug is fine.
Worked example
Driving 14,000 km a year at 17 kWh per 100km is about 2,380 kWh. Saving 30 cents a kWh with the charger is about $714 a year, so an $1,800 charger pays back in roughly 2.5 years, then saves you money after that.
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