GridReady WNY Guide
Solar quotes & pricingWhy did three solar companies give me three different system sizes?
Same roof, different kW proposals? You are probably comparing different spreadsheets, not different realities.
Reviewed for WNY homeowners comparing multiple bids with conflicting assumptions and bundled scopes.
Quick answer
- Different system sizes are usually assumption differences, not math errors.
- Usage baseline, shading, setbacks, and future loads can all move kW sizing.
- Bigger is not automatically better if assumptions are inflated.
- Normalize inputs first, then compare price and scope.
Who this guide is for
- Homeowners comparing multiple bids with different system sizes.
Why this matters in WNY
- WNY roof geometry, tree cover, and older electrical systems increase assumption spread.
Why proposals diverge
Common assumption differences
| Category | How it changes system size | What to request |
|---|---|---|
| Usage baseline | Higher usage assumption drives larger kW | Use same 12-month usage baseline across all bids |
| Shade/orientation model | Different loss assumptions shift required array size | Ask for explicit shade and roof-plane assumptions |
| Setbacks/layout constraints | Usable roof area changes panel count | Require proposed layout with setback rationale |
| Future load assumptions | EV/heat pump projections inflate or justify upsizing | Document projected loads and timeline in writing |
| Scope/financing packaging | Bundled upgrades can mask real system economics | Itemize electrical scope and pricing structure |
Apples-to-apples decision framework
Normalize then compare
Step 1
Set one baseline
Choose one annual usage figure and one future-load scenario to use across all bids.
Step 2
Standardize assumptions
Require each installer to restate shade, setback, and production assumptions in writing.
Step 3
Separate scope layers
Split solar-only cost from panel upgrades, batteries, and financing effects.
Step 4
Compare outcomes
Evaluate projected production, bill impact, and resilience goals against your priorities.
Red flag
- Installer refuses to share assumption basis.
- Major scope inclusions/exclusions are left ambiguous.
- Sales narrative pushes 'more panels = always better' without usage logic.
Recommended tool
Use this first to pressure-test whether size differences come from assumptions or scope mismatch.
Open 60-sec $/W benchmarkRelated reads
FAQ
Is the biggest system always wrong?
No. It can be right if assumptions are explicit and aligned to real goals.
Should I choose by lowest $/W alone?
Only after assumptions and scope are normalized; otherwise price metrics can mislead.
Can financing change system sizing recommendations?
Yes. Packaging and payment framing sometimes steer system size proposals.