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Annual totals
Savings and payback
Winter vs summer savings comparison
See exactly how much lower your winter savings run compared to summer, in both seasonal totals and average monthly dollars.
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
One step to your comparison
Step 1
Enter your annual production and savings
Use figures from the solar savings calculator if you haven't worked these out yet.
Step 2
See totals and monthly averages side by side
The tool shows both the seasonal total and the average monthly figure for winter and summer, so you can set realistic month-to-month expectations. For all four seasons, see the seasonal savings variation calculator.
Understanding the winter and summer gap
The monthly reality
For a system saving $1,800 a year, average monthly savings run about $90 in winter versus $198 in summer, a difference of about $108 a month between the two seasons. That gap is worth knowing ahead of time so a lower winter bill credit doesn't feel like a problem with the system. The US Energy Information Administration's electricity data show how retail rates have moved, which is the starting point for any savings estimate.
Why winter bills naturally run higher
Lower winter production means smaller bill offsets, so winter bills will typically run higher than summer bills even with a perfectly functioning system. This is expected behavior, not a sign anything's wrong, and it's the same underlying pattern covered in the seasonal savings variation calculator. If you have not sized the system yet, start with the system size by monthly kwh usage and bring its kilowatt figure back here.
Cold weather isn't the culprit
Cold and cloudy are different things. Cold temperatures can actually improve panel efficiency slightly, it's shorter days and a lower sun angle that reduce winter production, not the cold itself. Annual totals still matter more than any single season's performance when evaluating whether solar makes sense for your home, similar to how the 25 year lifetime savings calculator looks at the full picture rather than any one period. For background on how solar power is generated, the solar explainer from the US Energy Information Administration is a solid starting point.
How utilities help smooth this out
Many utilities offer net metering with an annual true-up, letting summer credits carry forward to offset winter usage, which smooths out the seasonal swing over the full year rather than billing each month in isolation. See the annual true-up payment estimator for how that mechanism works in more detail. The production figure behind this estimate comes from the seasonal output calculator by latitude, which models output for your location and roof.
Questions
Frequently asked
For a system saving $1,800 a year, average monthly savings run about $90 in winter versus $198 in summer, a difference of about $108 a month between the two seasons.
Yes, that's normal and expected. Lower winter production means smaller bill offsets, so your winter bills will typically run higher than summer bills even with the same system, regardless of how well the system is performing.
Not necessarily, cold and cloudy are different things. Cold temperatures can actually improve panel efficiency slightly, it's shorter days and lower sun angle that reduce winter production, and annual totals still matter more than any single season.
Many utilities offer net metering with an annual true-up, letting summer credits carry forward to offset winter usage, which smooths out the seasonal swing over the full year rather than billing each month in isolation.