Community & shared solar
Community solar 25% offset calculator
See the subscription size and savings for covering a quarter of your usage, a common starting point for a first community solar subscription.
How it works
Two steps to your 25% offset numbers
Step 1
Enter your annual usage
A 25% offset uses a quarter of this figure as its target. Check whether this meets your provider's minimum with the minimum subscription size tool, since a quarter offset can sometimes fall below the threshold for smaller households.
Step 2
Add your credit rate and discount
These determine your actual dollar savings on top of the fixed 25% offset. If you're weighing whether to go bigger, compare this result against the 50% offset calculator.
Understanding a 25% offset subscription
Why some subscribers choose a smaller offset
A 25% offset requires a smaller subscription commitment and a lower total subscription cost than a full offset, which makes it a lower-risk way to try community solar. It's a reasonable choice for subscribers who want to keep their initial commitment modest, or whose usage is small enough that a larger offset would exceed a provider's practical size for their household. The DSIRE database lays out the same rules from the regulator's side.
What the smaller savings number actually reflects
Because only a quarter of your usage gets a discount, the dollar savings from a 25% offset are proportionally smaller than a 100% offset with the same discount rate. This isn't a worse deal per kWh, just a smaller slice of your total bill being addressed. Check the subscription cost per kWh tool to confirm your effective rate is the same regardless of offset size. A rooftop system aiming for a similar partial offset can be compared using the bill offset percentage calculator.
When a 25% offset makes the most sense
This offset level fits well if your household usage is on the lower end, if you want to test a provider before committing to a bigger share, or if you're planning to add more subscription later once you've confirmed the program works well for you. It also fits naturally alongside a partial rooftop installation, where community solar covers the remaining portion of usage. See the community vs rooftop solar comparison for that scenario. A modest starting offset can also make sense if a low-income solar program with enhanced discount terms applies to you, and the DSIRE database can confirm what's available in your specific state.
Moving to a larger offset later
If a 25% offset ends up feeling too small once you see your actual bill impact, most providers allow you to increase your subscription later, subject to available capacity. Run the 100% offset calculator to see what a full subscription would look like for comparison. The Department of Energy's community solar basics guide notes that well-designed programs shouldn't charge a fee for adjusting your subscription size, which is worth confirming with your specific provider.
Questions
Frequently asked
A 25% offset can still deliver meaningful savings at a lower subscription cost than a full offset, making it a reasonable entry point if you want to test community solar before committing to a larger share. A 10,800 kWh household with a 10% discount and a 25% offset saves roughly $38 a year.
A smaller offset means a smaller subscription commitment and lower total subscription cost, which can appeal to subscribers who want to limit their exposure to a new contract or who have a smaller usage baseline. It also leaves room to increase the subscription later if the program allows adjustments.
A 25% offset covers roughly a quarter of your annual electricity usage in bill credits, leaving about 75% of your usage billed at your normal utility rate. The exact dollar impact depends on your credit rate and subscription discount.
Many providers allow you to increase your subscription size after enrollment, subject to available capacity in the shared array and any limits in your contract. Check your enrollment agreement for the specific process and timing for adjusting your subscription size.