Electric vehicle owners who charge mostly at home and occasionally on the road notice a sharp price difference between the two. The gap comes from how commercial electricity is billed rather than from operator margins alone.
Demand charges dominate fast charging economics
Commercial electricity bills include a demand charge based on the highest rate of power drawn during the billing period, not only the total energy consumed.
A single fast charging session can pull as much instantaneous power as a small building. One car arriving in an otherwise quiet month can set the charge for that entire month.
That means a lightly used fast charging site can have a high cost per delivered kilowatt-hour simply because the demand charge is spread across few sessions.
The hardware itself is expensive and short-lived
A fast charging cabinet contains high-power electronics, cooling systems and liquid-cooled cables. It is closer to industrial equipment than to the box mounted in a home garage.
That equipment must be paid off over its service life, and outdoor units in road-salt climates do not last indefinitely. Replacement is planned rather than exceptional.
Site preparation adds more. Trenching, transformer upgrades and utility interconnection work can exceed the cost of the chargers, and all of it is recovered per session.
Home charging piggybacks on an existing connection
A home charger draws on service that already exists for the house. There is no new transformer, no site host, no payment processing and no card fee per session.
Residential rates are also structured differently, without demand charges in most markets. The homeowner pays for energy, plus fixed service charges they were paying anyway.
Many utilities go further with time-of-use plans that price overnight energy well below daytime energy, precisely because overnight demand is low and generation capacity sits idle.
Level two public charging sits in between
Slower public charging at workplaces, hotels and parking structures draws far less power, so the demand charge problem largely disappears and the hardware is much cheaper.
Those sites often price by time rather than energy, which shifts the cost calculation. A car that accepts power slowly pays more per unit than one that accepts it quickly.
Some hosts treat charging as an amenity and price near cost or free, since the point is attracting the customer rather than selling electricity.
What this implies about ownership costs
The running-cost advantage of an electric car is real but conditional on charging pattern. An owner with reliable home charging and an owner dependent on fast charging have different economics.
Apartment residents and street parkers face the second situation by default, which is why charging access rather than vehicle price often decides whether the switch makes sense.
Planning around this matters more than chasing the cheapest per-session rate. Where a car sleeps determines most of what it costs to fuel.