Monthly Energy vs. Energy Usage (kWh/mo)

I'm trying to run a simulation with only monthly energy usage, so I've entered this data from my monthly bill into the "Monthly Energy Usage" field under the "Electric Load" tab. When I run the simulation, my Monthly Energy (kWh) by month is different than my Energy Use Without System (which matches the data I entered). Does anyone know why these are different, and how I should interpret these differences?

Thanks,

Xaviar

Dear Xaviar,

I'm not sure which performance model you are using, but am guessing the PVWatts model. The "Monthly Energy (kWh)" variable is the system's total electrical output in each month. The "Energy use without system kWh/mo" is the building's total monthly electricity consumption without the PV system.

Best regards,
Paul.