Home ElectricityLoad Calculator

The average UK home has a peak electrical load of around 3–8 kW when common appliances run simultaneously. However, if you add an electric shower (9.5 kW alone), an EV charger (7 kW), and a heat pump (3 kW), a home can peak at 20+ kW. UK residential supplies are typically rated at 100 amps (23 kW at 230V). Everyday consumption averages 2,700–3,100 kWh per year — equivalent to roughly 7–8 kWh per day.

kW (kilowatts) measures power — how fast electricity is being used at any moment. kWh (kilowatt-hours) measures energy — how much electricity has been used over time. A 2 kW kettle running for 30 minutes uses 1 kWh. Your electricity bill charges you for kWh consumed, not kW. The calculator shows both: current load in kW and estimated consumption in kWh/month.

Under the 2026 price cap, the standard unit rate is approximately 24–25p/kWh. Economy 7 night rates can be 10–15p/kWh. Smart time-of-use tariffs (Octopus Agile, etc.) fluctuate hour by hour. Standing charges add around £100–£130/year on top of consumption. Use your actual tariff rate in the calculator for the most accurate cost estimate.

Heating and hot water are typically the biggest consumers — electric showers (9.5 kW), immersion heaters (3 kW), and heat pumps (3–5 kW) dominate when active. Washing machines and tumble dryers use 2–2.5 kW each during cycles. Electric ovens run at 2–3 kW. By contrast, modern LED lighting, TVs, and laptops use a fraction of older appliances. EV charging at 7 kW overnight can add 20–30 kWh per charge.

Not always — it depends on your existing load. A 7 kW EV charger draws 30 amps continuously. If your home already runs a high-load shower (40A), an oven (13A), and other appliances simultaneously, you may be close to the 100A supply limit. A qualified electrician should carry out a load assessment before installation. Load-limiting smart chargers can automatically reduce charging speed when other high-draw appliances are running, avoiding the need for a supply upgrade.

Run high-load appliances (washing machine, dishwasher, EV charger) overnight on cheaper off-peak tariffs if you have Economy 7 or a time-of-use tariff. Upgrade old appliances to A-rated models — they use 30–50% less energy. Switch all lighting to LED if you haven't already (saves £50–£100/year for a typical home). Install a smart thermostat if you have electric heating. Consider solar panels — even a 3.5 kW system can generate 3,000 kWh/year, covering a significant portion of typical usage.

Your home may need attention if: the consumer unit uses old rewirable fuses rather than modern MCBs and RCDs; circuits frequently trip; you have fewer than 20 circuits for a 4+ bedroom home; you're adding major loads like an EV charger, heat pump, or hot tub; or the wiring is over 25 years old. Any notifiable electrical work (new circuits, consumer unit changes) must be carried out by a Part P registered electrician in England and Wales.

A typical 3–4 kWp solar panel system (10–12 panels) generates approximately 2,700–3,500 kWh per year in the UK — enough to cover most of an average home's electricity use. Divide your annual kWh estimate from this calculator by 280 (average kWh per panel per year in the UK) to get an approximate panel count. Battery storage lets you use daytime solar generation overnight, maximising self-sufficiency.