kW vs kWh (power vs energy)
also: kilowatt · kilowatt-hour · demand charge · peak demand
Kilowatts measure power, the rate of energy use at a moment; kilowatt-hours measure energy used over time. Commercial electricity bills often charge for both.
A 2 kW heater running for 3 hours uses 6 kWh. Energy (kWh) drives most residential bills. Many commercial and industrial tariffs also include demand charges based on the highest average power (kW) drawn over a short interval, often 15 or 30 minutes, during the billing period, and these can be a large share of the bill.
This matters for product design: a device that shifts or smooths load (staggering compressors, pre-cooling, managing EV charging, discharging a battery) can cut demand charges without reducing total energy. It also matters for electrical infrastructure, which is sized for peak kW, not total kWh.
Founder takeaway
When modeling the value of an energy product, look at peak kW and the tariff structure, not only kWh saved.
sources
engineer review pending