Home solar cost and contracts

How Much Electricity Would a Home Use to Match a 15 kW Solar System?

Published · By the SolarPanelX editors · Prices and specs as of that date, from the pages under Sources

Summary

More than the average home in the highest-use groups of the federal housing survey. By NLR PVWatts estimates, 15 kW makes about 16,320 kWh a year even in Seattle, which is above the 15,489 kWh that homes of 3,000 square feet or more averaged in EIA's 2020 survey. Add two electric vehicles to such a home, about 21,440 kWh in total, and 15 kW covers roughly 90% in New York and three-quarters in Seattle.

Next to the biggest users

These are the RECS 2020 groups with the highest averages. A 15 kW system produces about 26,330 kWh a year in Phoenix, 19,370 kWh in New York, and 16,320 kWh in Seattle (south-facing, 20° tilt, 14% losses).

GroupAnnual electricity use15 kW share, New York15 kW share, Seattle
3,000 sq ft or more15,489 kWh125%105%
Six or more people14,730 kWh131%111%
Electricity as main heating fuel13,073 kWh148%125%
3,000 sq ft or more plus two EVsabout 21,440 kWh90%76%

The EV load multiplies the 27 kWh per 100 miles that the Department of Energy uses in its home-charging cost example by 11,026 miles, the average annual distance for a car in DOE's data. That comes to about 2,980 kWh per car.

Lawrence Berkeley National Laboratory found that 80% of homes installed in 2025 were about 12 kW or smaller. With 430 W panels, 15 kW is 35 modules (15.05 kW).

Sources

  1. U.S. EIA — RECS 2020, Table CE2.1 Annual household site fuel consumption (revised March 2024)
  2. NLR Developer Network — PVWatts API Version 8 (run by the editors on September 23, 2026: 1 kW, south, 20° tilt, fixed roof mount, standard module, 14% losses; scaled to 15 kW)
  3. U.S. DOE Alternative Fuels Data Center — Charging Plug-In Electric Vehicles at Home
  4. U.S. DOE Alternative Fuels Data Center — Average Annual Vehicle Miles Traveled by Major Vehicle Category
  5. Lawrence Berkeley National Laboratory — U.S. Distributed Solar and Storage 2026 Data Update (August 2026)

We have not tested these products. Specs, prices, stock and terms are as published on these pages on the date above and can change; check the manufacturer or retailer before you buy.

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