Path-Q Solar
Can a solar array on a detached building offset electricity used at the main house?
Answer
Sometimes, but it depends on how the buildings are metered, electrically connected, owned, and treated by the utility or energy program. A physically separate array may offset the main house only if the applicable metering, interconnection, and credit-allocation rules allow it; otherwise, the array may primarily serve the detached building's meter.
Key points
- Separate meters do not automatically share solar production or credits.
- A shared electrical connection, dedicated interconnection, or approved allocation arrangement may be relevant.
- The physical wiring plan and the utility's billing treatment must both be evaluated.
What it depends on
- Number and type of meters and the electrical relationship between buildings
- Utility tariff, interconnection rules, and any applicable energy-credit program
- Property ownership, service territory, system location, and building loads
Risks and trade-offs
- Expected bill savings may not occur if credits cannot be transferred between meters.
- Connecting buildings may require trenching, service changes, or electrical upgrades.
- A design optimized for one meter may produce different value than one serving multiple loads.
Information you may need
- Recent bills and meter numbers for both buildings
- Single-line electrical diagram and service-connection details
- Current written utility rules for multi-meter generation and credit allocation
Your next step
What to do next
Ask the utility and a qualified solar provider to confirm in writing how generation from the detached building would be metered and credited before selecting the system design.
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Some details may depend on your location, installer, utility, incentives, regulations, or specific property.
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