GridReady WNY Guide
Solar quotes & pricingProposal Autopsy: The Production Estimate That Only Works in July
Production numbers get inflated more than any other line item in a WNY proposal. The kWh-per-kW-DC ratio exposes the inflation in one step and gives you a number to hold the installer to.
Redacted from a 2026 West Seneca proposal. Kilowatt-hour math preserved exactly; shading inputs and installer name anonymized.
Quick answer
- WNY south-facing roofs produce 1,100 to 1,250 kWh per kW-DC per year in realistic scenarios.
- Proposals quoting above 1,300 are using national-average modeling, ignoring WNY cloud cover and lake effect, or both.
- Divide the proposed year-one kWh by the kW-DC system size. That ratio is your sanity check.
- Ask which software, what shading inputs, and what year-one expected kWh by month. Most installers have these numbers; some will not share them.
Who this guide is for
- Homeowners in WNY whose proposal promises production that feels too good.
- Anyone comparing two proposals on the same roof with different kWh numbers.
The proposal
An 11.6 kW-DC system for a West Seneca homeowner. The proposal is professional, includes a real 3D roof rendering, and has a year-one production number that looks great on page one. The homeowner was comparing it against two other WNY installers. The difference between this proposal and the others was almost exactly 2,000 kWh per year, which showed up as roughly $450 per year of extra projected savings. The whole deal rotated around that number.
Proposal E (redacted)
West Seneca, NY · 11.6 kW-DC · cash price, full roof assessment
System summary
Production estimate
- 1
Specific, fine.
- 2
Microinverters are a reasonable choice for a roof with 'minimal' shade. Fine.
- 3
This is the number that does not survive the sanity check. 16,240 kWh on 11.6 kW-DC is a very high number for West Seneca, even on a great roof.
- 4
1,400 kWh per kW-DC per year is roughly Phoenix-level production. The realistic WNY band for a south-southwest roof with this pitch is 1,150 to 1,230. This proposal's estimate is about 15% above realistic, compounded across 25 years.
- 5
The 90% guarantee sounds strong, but 90% of an inflated number is 14,616 kWh. A realistic estimate at 100% would be 13,920 kWh. The guarantee is worth less than it looks.
- 6
'Proprietary modeling tool' is not an answer. Every credible installer uses Aurora, Helioscope, Solargraf, or equivalent and will name it. Refusing to name the tool is a flag.
- 7
A monthly breakdown would have exposed the issue. A WNY install produces roughly 40-50% of its annual total in the four months May through August, and roughly 10% in December and January combined. If the monthly numbers had been included, the homeowner could have spot-checked the winter figures against any neighboring install.
- 8
Realistic, matches the homeowner's stated annual usage of around 11,000 kWh.
- 9
80% offset math only works if the 16,240 kWh estimate is real. On the realistic 13,900 kWh number, the offset drops to about 68%, and savings fall by roughly $500 per year.
- 10
4.2% annual rate inflation over 25 years is higher than NY's long-run average and stacks on top of the inflated production. Dropping to 3% and correcting production drops the 25-year savings projection by about $22,000.
The kWh-per-kW-DC sanity check
The math is one step: divide the proposed year-one kWh by the system size in kW-DC.
16,240 kWh / 11.6 kW-DC = 1,400 kWh per kW-DC per year.
For WNY in 2026, the bands are:
- 1,050 to 1,150: typical south-facing roof with some shading, or an east-west split install. The honest middle.
- 1,150 to 1,250: clean south-facing roof, moderate pitch, minor shading. This is the upper realistic band for most WNY homes.
- 1,250 to 1,300: excellent south exposure, steep optimum pitch, no trees, no winter shading. Rare but achievable on a new-build ranch in a flat suburb.
- Above 1,300: either a modeling error, a non-WNY assumption, or an installer trying to make the savings math look better than it is.
This proposal is at 1,400, which means it is about 15% above the realistic upper band for the house. Over 25 years with utility-rate inflation compounded, that 15% is roughly $22,000 of imagined savings.
What to watch for in the production estimate
- Year-one kWh that divides to more than 1,300 per kW-DC per year on a WNY roof.
- Production software that is 'proprietary,' unnamed, or unexplained.
- No monthly production breakdown anywhere in the proposal.
- Shading described qualitatively ('minimal') without a 3D irradiance report.
- Production guarantees quoted as a percentage of a too-high estimate.
The calm asks
Three asks that expose the inflated estimate
[ ] Ask for the monthly production breakdown.
Twelve numbers, January through December. Every modern solar modeling tool outputs this. A refusal to share it is a refusal to defend the annual total.
[ ] Ask which modeling software was used.
'Proprietary' is not a software. Aurora, Helioscope, and Solargraf are the three most common. Any named tool is fine. Unnamed tooling is a flag.
[ ] Ask for the irradiance report or shading plot.
Credible proposals include a 3D rendering of your roof with sun-exposure hours per section. If your installer has one, they will share it; if they do not, the shading was not properly modeled.
If this is your proposal
Ask the three questions. If the answers come back cleanly, the number might be legitimately high for a great WNY roof. If the answers deflect, the 1,400 figure is sales theater. Either way, ask for a revised proposal with the corrected production number and the matching savings story. Any installer with a clean process can produce this inside a week.
Recommended tool
The $/W sanity tool also flags production numbers that are out of band for WNY, alongside the price-per-watt check. Two sanity tests on one page.
Open run the quote sanity checkRecommended tool
If you already have solar, the production sanity tool compares your real kWh to the WNY band. Useful if you signed based on an inflated estimate and want to know how far off you landed.
Open check whether your current install is in bandMethodology note
Production bands cited here are drawn from NREL's PVWatts tool set to Buffalo, NY coordinates with realistic tilt, azimuth, and shading inputs, cross-checked against the site's aggregated reader-submitted first-year figures from WNY installs. Your specific number depends on your roof. The $22,000 25-year savings delta assumes the corrected production number, a 3% annual utility-rate assumption instead of 4.2%, and current NYSERDA + federal incentive structure. The point of this walkthrough is not to land a specific savings figure; it is to show how a single too-high production number compounds into tens of thousands of dollars of imagined savings.
Keep reading
- Does solar actually work in Buffalo winters?
The full breakdown of WNY seasonal production, snow shedding, and what to expect month by month.
- Autopsy: the phantom panel upgrade
What happens when the proposal skips a costly line item entirely.
- How to read a solar quote before you sign
The five numbers every proposal should answer to.
- Solar year 8 reality check
What production degradation and NY rate trajectories actually do to the savings story.
FAQ
What is a realistic year-one production number for a WNY south-facing roof?
About 1,100 to 1,250 kWh per kW-DC per year for a modern install with minor shading. Straight south, steep pitch, zero shade sets an upper band around 1,280. Partial shade or east/west orientations drop this into the 900 to 1,050 range. Numbers above 1,300 almost always mean the modeling ignored WNY's real sun-hour profile.
Why does WNY produce less than the national average?
Lake-effect cloud cover, winter snow on panels, and a shorter peak-sun-hours profile than the Sunbelt. Buffalo averages roughly 4.0 peak sun hours per day; Phoenix averages 6.4. If your proposal uses Phoenix-style math, your bill will not match the savings chart.
Does the production estimate matter if the installer has a 'production guarantee'?
It matters more. A production guarantee that promises 90% of a too-high estimate is worth less than a production guarantee at 95% of a realistic estimate. Always check the guaranteed number against the WNY band before comparing installers.
What software should the installer be using?
Aurora Solar, Helioscope, and Solargraf are common. Any of them is fine if the shading inputs reflect your actual roof. The question to ask is not which software, but what 3D shading model they ran and whether you can see the irradiance report.