Where a Family's Energy Goes

I wanted to know how much energy my AI coding agents use. The answer on its own told me nothing, so I went looking for something to compare it with, and ended up building an energy budget for a whole household.

The chart below is that budget, for an imaginary family of four in a 65 m² house (not mine unfortunately) in a temperate European climate. The starting numbers come from the EIA's residential energy survey, Eurostat and the ODYSSEE database, filled in with typical appliance wattages. If your family is not my imaginary one, click any bar to open its assumptions and change them. Every row except AI counts the energy that arrives at the house or the vehicle, whether it comes as gas, oil, wood, fuel or electricity. The AI rows count electricity used in the data centre.

Heating is the biggest thing in the house. Around 60% of the energy a European home uses goes into keeping it warm, which is why insulation matters more than every appliance put together. Swap the gas boiler for a heat pump and the saving is more than half of everything else the house uses. Pick an old uninsulated house instead and heating alone climbs to about 14,400 kWh.

The shocking surprise for me was the shower. A daily 7-minute shower takes about 2 kWh, and for a family of four that adds up to three times the TV, the games console, the lights, the computers and the hair dryer combined. I love long hot showers and ironically I spend most of my time under the shower thinking how to solve world problems. Turns out that's the worst possible way to go about it.

Transport is bigger than the house. A petrol car doing 15,000 km a year burns about 9,300 kWh of fuel, more than the heating and the showers put together. An electric car covers the same distance on about 2,700 kWh, because an electric motor wastes far less than an engine. Fortunately I drive far less than 15,000 km a year. A smaller second car doing 6,000 km a year adds another 3,200 kWh. One short-haul holiday flight for four uses more energy than a year of showers, and a single long-haul return trip for the family uses more than a year of heating.

And the AI? My agentic coding, about 300 million tokens a month, comes to roughly 155 kWh a year. That is the same as the family's TV. Now I don't feel that guilty. Casual chats barely register: twenty a day is about 2.5 kWh a year, less than charging a single phone. These two are the least certain numbers on the page, because no AI lab publishes energy per token. I estimated them from list prices, so treat them as good to within a factor of two or three, and use the Estimate switch to see the range.

The things that feel wasteful barely register. The boring ones decide the total: the walls, the showers and the car.