What Is Battery Attach Rate?

The national solar-plus-storage attach rate climbed to 45% in Q1 2026 from 38% a year prior, and residential battery storage as a category grew 51% year over year in 2025, to 3.1 GWh. That growth is happening while overall US residential solar installations are forecast to contract 18% to 21% in 2026, which makes battery attach the one segment moving the opposite direction of the headline market trend.

The driver is not purely consumer enthusiasm for backup power. In California specifically, NEM 3.0 cut solar export credits by roughly 75% starting in April 2023, which shifted battery storage from a nice-to-have to functionally required for system economics to work, since exported, unused solar production is now worth far less than it used to be. Nationally, installers are also leaning on batteries as a customer lifetime value lever, layering a second product onto the same homeowner relationship instead of relying on the original system sale alone to justify rising acquisition cost.

For appointment buyers, this means a growing share of qualified consultations now include a real battery-attach conversation, not just a panel-count and financing conversation, and vendors selling into this space need qualification criteria that capture that intent.