3.6 The builder-installed solar trap

Starting in 2020, California's Title 24 Solar Mandate required new homes to come with solar pre-installed. Builders typically sign exclusives with companies like SunPower / Sunrun. The result:

• Sticker price is 2–3× market. $40,000–$60,000 may only buy a 5–6 kW system with no battery.
• The system is sized to "just clear Title 24," which is dramatically undersized for actual usage.
• It's often a lease or PPA, so the homeowner doesn't own the system and doesn't get the tax credit either.
• Upgrading is painful: touching the system can void NEM 2.0 grandfathering.

For an upgrade path that preserves the legacy NEM grandfathering, see section 5.8 on adding a Non-export system.