Common Solar + Storage Package Specs

The four packages

Installers quote a small set of recurring configurations. The array is sized to a home’s annual use, and the battery is sized either for essential-load backup or for whole-home backup. We price solar at EnergySage’s size-specific figures, about $2.68 per watt for a 6 kW system and $2.56 for 12 kW (EnergySage solar cost data), and batteries at the $1,130 per kWh median (EnergySage H1 2026 press release).

The 8 kW plus 13.5 kWh package matches the U.S. Department of Energy’s residential solar-plus-storage benchmark, modeled at $4.33 per watt or about $34,640, with operations and maintenance of $64 per kW-year (DOE solar system cost benchmarks). Our $36,215 estimate sits about 4.5% above it.

Two markets, two answers

The same equipment produces very different economics depending on how a utility credits exported solar. We modeled each package hour by hour for a full year in two markets, using NREL’s PVWatts production model (NREL PVWatts v8):

• Net metering market (Kansas City area): full retail credit for exports at a flat 19¢ per kWh, near the national average residential rate (EnergySage solar savings data), netted over the year.
• Net billing market (Inland Southern California): SCE’s TOU-D-PRIME rate, with summer weekday peak at 61¢, off-peak at 26¢ and winter mid-peak at 45¢ (SCE TOU-D-PRIME plan), and exports credited at SCE’s 2026 Solar Billing Plan average values of 3–21¢ plus a 1.6¢ bonus (SCE Solar Billing Plan; SCE Solar Billing Plan sample bill).

In each case the home uses about as much electricity in a year as its array produces, which is how installers commonly size an array. The battery charges from surplus solar and discharges whenever the home draws from the grid, keeping a 20% backup reserve and losing 11% of energy in the round trip.

Under full retail net metering, the grid behaves like a perfect free battery: every exported kWh earns back the full retail price. A physical battery cannot beat that, and its round-trip losses make the result slightly worse. Under net billing, exports earn a fraction of the import price, so storing midday solar for the evening peak is worth far more. In our net billing model, the 8 kW package with one battery earns $3,364 a year against $1,968 for solar alone.

This is why battery attachment rates track net metering policy. States continue to revise export compensation; the NC Clean Energy Technology Center tracks those changes quarterly (NC Clean Energy Technology Center, 50 States of Solar Q2 2026).

Value the bill model leaves out

Bill savings are only one stream. The battery in each package also provides backup and grid flexibility, which matter differently to different audiences: resilience to the occupant, dispatchable capacity to a utility or aggregator, and enrolled kW to a program manager.