System Production is a complex calculation that involves several factors.
Globally a formula E = A x r x H x PR is followed to estimate the electricity generated in output of a photovoltaic system.
E is Energy (kWh), A is total Area of the panel (m²), r is solar panel yield (%), H is annual average solar radiation on tilted panels and PR = Performance ratio, constant for losses (range between 0.5 and 0.9, default value = 0.75). r is the yield of the solar panel given by the ratio : electrical power (in kWp) of one solar panel divided by the area of one panel.
An example might be if 360w panels are changed on a design to 435w panels, and the panel count is reduced by 3 to keep system size small and cost down. The result would be that the production would go down (which changes the offset). According to the formula, A is total area of the panels. Even though the wattage on the panel was higher, reducing the area of the collective system would affect the production.
There are also other variables that will affect production of a system such as shading and placement on the roof. If panels are moved to other areas of a rooftop that will also affect production as well due to positioning and azimuth calculations.
Understanding the variables that make up the System Production can help customers and Sales Reps figure out how to build the highest producing system while keeping the cost of the total system down.
How Existing Solar Systems Affect the Production Total
If a homeowner already has a solar system and you've entered an existing system on the deal's design, Enerflo includes that existing system's production in the total production figure shown on the proposal.
For example: if the new design produces 30,806 kWh/year and the existing system produces 30,138 kWh/year, the proposal will show a combined production of approximately 60,944 kWh/year.
This is intentional — it reflects the homeowner's total solar production after the new system is installed alongside the existing one.
If the Number Looks Unexpectedly High
Check whether an existing system has been entered on the deal:
Go to the Design stage of the deal.
Look for the existing system button in the top-right corner of the design screen.
If an existing system is present and should not be, you can modify or remove it there.
If no existing system should be on the deal, removing it will bring the production figure back to just the new design's output.