“Output” refers to the maximum potential power of a given energy shingle. Output is measured in watts (W) or kilowatts (kW). “Generation” refers to the electricity produced over time by the entire photovoltaic (PV) system. Generation for a PV system is measured in kilowatt hours (kWh). Actual generation of an energy shingle system may be lower and vary based on site and weather conditions.

GAF Energy’s base warranty (included in every project) covers the energy shingle’s output, or rated capacity to produce. Homeowners may purchase an enhanced warranty that can cover the system’s generation, which is based on the expected production of the system over time.

Think of it like a car’s fuel efficiency. A car with a 20-gallon gas tank and a fuel efficiency rating of 20 miles per gallon has the potential to drive 400 miles in perfect conditions before the fuel runs out. Therefore, the car’s maximum mileage starting on a full tank of gas is 400 miles. The actual mileage with a full 20 gallons of gas, however, is subject to various, often less-than-perfect driving conditions (like rough terrain, stopping and starting due to traffic, weather), and therefore is typically shorter than 400 miles. The difference between potential power output and generation in a PV system is similar to the difference between fuel efficiency and overall mileage of a car. In both cases, external conditions can impact the actual result.