Solar Savings Calculator

How the estimate is built

Your bill and rate reveal your consumption; your region's peak sun hours determine how big a system covers it. The calculator sizes an array to offset most of your usage, prices it at a typical 2026 installed cost, and divides to a payback estimate. The 30% federal Residential Clean Energy Credit ended for systems placed in service after 2025, so any state or utility incentive you qualify for shortens that payback from there.

The result is deliberately conservative, an 85% bill offset and standard pricing, so surprises run in your favor.

What moves the real number

• Roof orientation and shading, south-facing, unshaded roofs beat the average
• Your utility's net-metering or export rules (they vary widely)
• Time-of-use rates, pairing a battery captures peak pricing
• State and utility incentives, which vary widely, check the Savings Finder

Solar plus storage: the 2026 default

As utilities cut export compensation, storing your surplus beats selling it in more and more states. A Powerwall 3 with its built-in solar inverter makes the combined system simpler and cheaper than bolting the parts together, and a single install keeps permitting, interconnection, and any state rebate filing in one package.

Stress-testing your result

Good solar decisions survive pessimistic inputs. Rerun the numbers with your rate 20% lower (utility discounts happen), production 15% under (weather varies), and the payback stretched accordingly. If the project still clears your threshold, most do in decent sun with current incentives, you're deciding on robust ground rather than a sunny-day brochure.

Then test the optimistic direction that actually matters: rates in most territories have climbed steadily for a decade, and every increase accelerates payback on a system whose costs froze at installation. Solar's quiet superpower is that it's a fixed-rate contract with your own roof.

Roof reality: what changes the modeled number

South-facing unshaded roof at moderate pitch: the model holds. East-west split: expect ~10-15% less annual production but often better alignment with morning and evening usage, sometimes worth more per kWh under time-of-use rates. Shading from trees or neighbors: the variable that demands on-site measurement, since even partial shade patterns move production meaningfully.

Roof age belongs in the plan too: panels outlive shingles, and re-roofing under an array costs real money. If your roof has under ten years left, sequence the roofing first, a coordination we handle routinely.

The production curve vs your consumption curve

Solar's economics live in the overlap between when panels produce (midday peak) and when your home consumes (morning and evening shoulders). Full net metering made the mismatch free; reduced-export tariffs price it, and batteries, load scheduling, or east-west panel splits close it.

Practical translations: run the dishwasher and laundry at noon, schedule EV charging into the production window on work-from-home days, and let a battery time-shift the rest. Households that align consumption with production capture 15–25% more value from identical hardware, behavior as a system component.

What 25-year equipment warranties actually promise

Panel warranties run two layers: product (materials and workmanship, typically 12–25 years) and performance (guaranteed output floor, commonly 84–92% at year 25). Inverters and batteries warrant shorter, 10–12 years, which is why quality quotes price the mid-life inverter replacement honestly rather than hiding it.

The bankability behind the paper matters as much as the terms: warranties from manufacturers likely to exist in year 20 are worth more than aggressive numbers from newcomers. It's a selection criterion we apply for you at design time. The warranty conversation also frames maintenance honestly: quality systems need almost none, occasional visual checks and keeping panels unshaded, which is exactly what 25-year paper assumes and what cheap installs quietly violate.