Collect a year of usage if possible
Use the kilowatt-hour figures from your electricity records, not only the amount paid. Include all months so the installer can see seasonal differences. Note any missing months rather than filling them with guesses.
Describe changes that the past year does not capture: an EV, electric heating, a home addition, or a different occupancy pattern. If the home is new, the proposal should explain the assumptions used instead of presenting estimated use as measured history.
Understand what panel-count arithmetic tells you
As a simple example, 20 panels rated at 400 watts each total 8,000 watts, or 8 kW, of panel nameplate capacity. That does not mean the array produces 8 kW at every moment or a fixed number of kilowatt-hours each day.
The annual generation estimate requires additional assumptions about the installation and operating conditions. The example is arithmetic only; it is not a Sun Ray equipment offer or a recommendation for your home.
Ask for the inputs behind the estimate
| Input | Why to review it |
|---|---|
| Electricity usage | Establishes the demand the proposal is intended to address. |
| Panel rating and quantity | Defines the proposed array’s nameplate size. |
| Roof or site layout | Shows where the equipment is expected to fit. |
| Exposure and shading | Affects the generation assumptions. |
| Equipment and losses | Affects the modeled output of the complete system. |
| Future changes | Helps explain why the proposal differs from last year’s usage. |
Use an estimate as a decision aid
PVWatts provides modeled production estimates for grid-connected solar using user inputs. A model is a starting point to review, not a site assessment or guaranteed output. Ask the installer to explain the assumptions that matter for your property.
Send Sun Ray your address, available electricity records, roof information, and goals. New systems receive a project-specific quote. If backup power is also a priority, list the desired loads separately so solar generation and battery storage are planned for their respective purposes.