A tile roof, a 1979 panel, and a summer bill that would not come down
The Ashford residence
System9.2 kW rooftop solar, 13.5 kWh storage, 200A service upgrade
Challenge
Two previous contractors had quoted an array roughly twice the size of what the household actually consumed, on the assumption that bigger is better. Neither had opened the electrical panel. The original 1979 service could not have accepted the systems they proposed without an upgrade that neither quote mentioned.
Approach
We pulled twelve months of billing history and found that the household was not a heavy annual consumer at all. The problem was concentrated almost entirely in the four-to-nine evening window through June, July and August. That is a load-shifting problem, not a production problem. We designed a right-sized array paired with storage, upgraded the service to 200A first, and set the battery to discharge through the peak window.
Outcome
The system now covers the household through the evening peak on stored production rather than exporting at low value at midday and buying back at the top of the rate schedule. The customer reports a summer bill of thirty-one dollars against four hundred and twelve for the same month the year before.
- Roughly halfArray size against original quotes
- Covered by storagePeak-window grid draw
- $412 to $31Reported July bill
- 52 daysTime from contract to switch-on
