Nebenkosten by Household Size: Why a Single Person Budgets Differently Than a Family

The Nebenkosten advance payment shown in an apartment listing is usually based on floor space, not on how many people will actually live there. But for actual consumption, household size makes a real difference, especially for electricity and water.

Electricity consumption by household size

The Stromspiegel, an initiative backed by the German federal government through the organization co2online, clearly distinguishes annual consumption by household size. A two-person household in an apartment without electric hot water preparation uses on average about 1,900 kilowatt-hours a year. A single-person household sits noticeably lower, while households of three or more reach correspondingly higher figures — appliances like a fridge or router can be shared, but individual consumption for lighting, cooking and hot water rises with every additional person.

Water consumption per head stays fairly constant

Drinking water works differently from electricity. According to statistics from the BDEW, the nationwide average is 121 liters per person per day, regardless of household size. That means a household's total water consumption scales almost proportionally with headcount: a two-person household uses roughly twice as much water as a single-person household, and in apartments without an individual water meter, that shows up directly as a larger, per-occupant share of Nebenkosten.

Why heating costs barely depend on headcount

Unlike electricity and water, a home's heating needs depend mainly on floor space and building insulation, not on how many people live there. That's why the Heizkostenverordnung mandates area-based billing for most of this cost, combined with a mandatory consumption share of 50 to 70%.

What this means for your own budget planning

If you're moving in with a partner or a bigger family, you should adjust the electricity portion of your budget upward more than the landlord's advance payment alone suggests, since that prepayment mostly reflects area-dependent costs like heating. Water, by contrast, tracks headcount fairly reliably and can be roughly estimated using the BDEW benchmark of 121 liters per day.

For the full breakdown of what each individual cost type typically runs, see our monthly utility cost overview. If two people are moving in together and want to understand what that means for liability, not just cost, see our guide on monthly costs for a two-person apartment. And to understand how landlords are legally allowed to split costs between tenants in the first place, check our guide on square meter vs. person-based billing.

Frequently Asked Questions

How much electricity does a two-person household use on average?

According to the Stromspiegel from co2online, about 1,900 kilowatt-hours a year in an apartment without electric hot water preparation.

Does water consumption rise proportionally with household size?

Yes, the BDEW benchmark of 121 liters per person per day applies largely regardless of household size, so total consumption roughly doubles when a second person moves in.

Why don't heating costs rise as much as electricity and water with more people?

Because heating needs depend mainly on floor space and building insulation, so they're billed mostly by area rather than by occupant count.

How should I adjust my Nebenkosten budget when someone moves in with me?

Expect the electricity share to rise noticeably, while the landlord's Nebenkosten prepayment often stays about the same, since it's mainly based on floor space.