Savings and payback
See your savings, production, and cost per kW of installed capacity, the standard industry metric for comparing systems regardless of panel wattage.
For planning purposes only, not financial or tax advice; confirm figures with a licensed installer or tax professional before making a purchase decision.
How it works
Step 1
Use the results from the solar savings calculator if you haven't worked these out yet.
Step 2
Optionally include your total system cost to also see cost per watt, a benchmark commonly used to compare quotes across installers, alongside the savings per panel calculator if you want both views.
Panel wattage varies significantly between manufacturers and models, from around 350W to over 450W for common residential panels, so panel count alone isn't a fair way to compare two different systems. Savings per kW normalizes for that difference entirely, which is why it's the standard metric used across the solar industry for comparing system value. For background on how solar power is generated, the solar explainer from the US Energy Information Administration is a solid starting point.
US residential solar typically runs $2.50 to $3.50 per watt installed before incentives. A 6.5 kW system at $22,000 works out to about $3.38 per watt, within that typical range, similar to the ballpark used in the payback period calculator example. Use this figure to sanity check a quote against broader market norms. If your production estimate feels uncertain, the specific yield calculator gives you a second check on annual output.
Specific yield, measured in kWh per kW per year, is a standard industry term for how much energy a system produces relative to its rated capacity. A 6.5 kW system producing 9,490 kWh a year has a specific yield of about 1,460 kWh per kW, which varies meaningfully by location, roof orientation, and shading, independent of system size. Compare against the cost per kWh produced calculator for the cost side of that same production figure. The US Department of Energy's homeowner's guide to going solar walks through the same decision step by step.
Just like the savings per panel calculator, dividing both cost and savings by the same kW figure cancels out mathematically, so payback per kW always equals payback for the whole system. The system size comparison by panel brand and wattage is the quickest way to check whether the system size behind this estimate fits your roof and usage.
Questions
Panel wattage varies significantly between manufacturers and models, so panel count alone isn't a fair way to compare systems. Savings per kW normalizes for that difference, making it the standard metric used across the solar industry for comparing value.
US residential solar typically runs $2.50 to $3.50 per watt installed before incentives. A 6.5 kW system at $22,000 works out to about $3.38 per watt, within that typical range.
Specific yield, measured in kWh per kW per year, is a standard industry term for how much energy a system produces relative to its rated capacity. A 6.5 kW system producing 9,490 kWh a year has a specific yield of about 1,460 kWh per kW, which varies by location, orientation, and shading.
No, mathematically they're identical. Dividing both system cost and savings by the same kW figure cancels out, so payback per kW always equals payback for the whole system, just like the equivalent calculation per panel.