What if your house made its own power?

Most homes get their electricity through wires from far away.

But some homes make their own, with solar panels on the roof. What if your home did that too?

Most homes get all their electricity from the grid, through wires that come from power plants far away. But more and more homes make some of their own.

In this thought experiment, imagine your home made its own power. You can follow three ideas: solar panels on the roof, a battery to save electricity for later, and a heat pump that warms the house using a little electricity to move a lot of heat. What could each one do, and what are its limits?

Households can add their own generation, storage and efficient heating. The main residential technologies are rooftop photovoltaics, behind-the-meter batteries and electric heat pumps.

This thought experiment considers a home adopting each in turn and asks what physics and published data say about their output, their losses and their dependence on weather, season and the house itself. Outcomes for any particular home are ideas, not predictions.

Homes use electricity for lights, fridges, computers and much more.

An average home in the United States uses about 30 kilowatt-hours every day.

The U.S. Energy Information Administration (EIA) says that in 2022, the average American home bought about 10,791 kilowatt-hours of electricity in the year, about 899 a month, or roughly 30 a day. That powers lights, the fridge, computers, washing machines and, in many homes, heating and cooling.

Homes vary a lot. In 2022, homes in Louisiana bought the most electricity on average, about 14,774 kilowatt-hours, and homes in Hawaii the least, about 6,178.

EIA reports that in 2022 the average U.S. residential customer purchased 10,791 kWh (about 899 kWh a month), from 14,774 kWh in Louisiana to 6,178 kWh in Hawaii. EIA cautions that purchases understate consumption in homes with solar: in 2020, RECS estimated Hawaii household consumption at 7,976 kWh, against purchases of 6,446 kWh, a gap filled partly by rooftop PV.

Space heating and air conditioning made up 52% of household energy use in 2020, which is why heating technology matters as much as electricity supply.

Let's pretend your house has solar panels on the roof. In the daytime, they make electricity.

A battery saves some for the evening. A heat pump keeps the house warm.

Imagine solar panels covering your sunny roof. On a clear summer day, they might make more electricity than the house uses at noon, and nothing at all after sunset. A battery could save the spare daytime electricity for the evening, and a heat pump could keep the house warm using much less electricity than an ordinary electric heater.

In Olly's solar panel lab, one rooftop-sized panel at 40° north makes about 2.3 kilowatt-hours on a clear June day but only about 1.2 in December. So a home using 30 a day might need a dozen or more panels, and still use the grid in winter. That is an idea, worked out from a simple model.

Rooftop PV output tracks the Sun: in the solar-panel model, a 1.7 m², 20% panel tilted 30° at 40° N yields 2.32 kWh on a clear 21 June and 1.19 kWh on 21 December. Matching 30 kWh a day might take roughly 13 such panels in clear summer weather and about twice as many in winter, before clouds: an estimate from a simplified model, not a design.

A battery could shift midday surplus to evening, with some loss; a heat pump could cut the electricity needed for heating, depending on climate and house. These are ideas, not predictions.

Solar panels turn sunlight into electricity. Batteries save electricity for later.

A heat pump does not make heat. It moves warmth from outside into the house, even on chilly days!

Solar panels turn sunlight straight into electricity, so they only work when light reaches them. A battery stores electricity as chemical energy and gives most of it back later; the EIA notes storage always gives back a little less than it took in.

A heat pump is clever. Instead of turning electricity into heat, it uses electricity to move heat from the outside air into the house. The EIA says air-source heat pumps typically move 2 to 4 units of heat for every unit of electricity they use, while an ordinary electric heater makes just 1.

PV converts photons directly to electricity, so output is set by irradiance. Batteries are secondary sources with negative net generation: EIA notes that storage systems use more electricity for charging than they discharge.

Heat pumps move heat from outside to inside in winter; their coefficient of performance (COP), the heat moved per unit of electricity, is typically 2 to 4 for air-source models, versus a thermal efficiency of 100% for resistance heating. EIA cautions, though, that costs depend heavily on the home and climate: a resistance heater in a small, well-insulated Southern home could cost less to run than a heat pump in a large, drafty Northeastern one.

Many homes already have solar panels on their roofs. Some also have batteries.

More and more homes use electricity to keep warm.

In the United States in 2025, small solar systems, mostly on or near buildings, made about a quarter of all solar electricity, and homes made about two thirds of that. Some homes also have batteries: in 2021, U.S. utilities reported 740 megawatts of home battery capacity, often charged by solar panels.

The EIA notes that batteries owned by homes and businesses can provide backup electricity during power cuts. And in 2024, 42% of U.S. households said electricity was their main heating fuel, while 47% used natural gas.

EIA: small-scale PV accounted for about 24% of U.S. solar generation in 2025, with residential systems producing 68% of that; most small-scale systems are on or near buildings. In 2021, utilities in 42 states reported 1,094 MW of small-scale battery capacity associated with customer PV, 740 MW of it residential, and EIA notes customer-owned storage can provide emergency backup during outages.

Census data reported by EIA show 42% of households used electricity as their main space-heating fuel in 2024 and 47% natural gas. Air-source heat pump technology improvements have contributed to electricity's growing share, especially in colder climates.