Solar Quote Comparison Worksheet
A side-by-side sheet that brings up to three solar and battery proposals down to the same metrics, size, price per watt, production per watt, savings assumptions, warranties, installer, and contract terms, so the spread between them finally makes sense.
Reviewed for 2026, updated September 8, 2026.
Two proposals for the same roof can differ by a wide margin in price, size, and projected output, and the differences are rarely where the cover page suggests. One quote leads with a monthly payment, another with a lifetime savings figure, a third with a panel brand, and none of them volunteers the assumptions underneath. This worksheet strips each proposal down to a common set of line items so you can read them on substance. One row per metric, one column per quote, and a final column reminding you why the number matters. The example cells are placeholders: replace every one marked with your figure, and treat the calculated rows as the ones that do the real work, because price per watt and production per watt are the only fair way to compare a small premium system against a large budget one.
Fill it in before you speak to any of the salespeople a second time, so that your follow-up questions come from the gaps in the sheet rather than from their pitch. The Home Solar Payback and Lifetime Savings Calculator at /tools/solar-payback-savings/ lets you re-run every projection with one set of conservative assumptions, which is the only way to compare payback claims built on different escalation rates. The Solar Array Size and Panel Count Estimator at /tools/solar-array-size-estimator/ gives you an independent size to hold against the first row. Our articles on comparing home solar quotes on substance rather than salesmanship at /blog/compare-home-solar-quotes/ and on why two quotes for one roof differ so greatly at /blog/two-solar-quotes-one/ explain each line in more depth, and the glossary at /glossary/ defines any term on the sheet you have not met before.
| Line item | Quote A | Quote B | Quote C | Why it matters |
|---|---|---|---|---|
| System size, kW DC | Your figure | Your figure | Your figure | The base for every per-watt metric below; check it against your own estimate |
| Panel model, wattage, count, and degradation guarantee | Your figure | Your figure | Your figure | Nameplate wattage says little; the cell generation and the guaranteed output in year twenty-five say a lot |
| Inverter architecture | String, optimizers, or micro | String, optimizers, or micro | String, optimizers, or micro | Decides shade tolerance, monitoring depth, and how a battery can be added later |
| Battery usable capacity, kWh, and continuous power, kW | None or your figure | None or your figure | None or your figure | Backup needs are set by kW and the circuits kept live; daily savings are set by kWh and your rate plan |
| Total contract price before incentives and financing | Your figure | Your figure | Your figure | Compare cash price to cash price; a monthly payment hides the cost of the loan |
| Price per watt installed, price divided by size | Calculated | Calculated | Calculated | The fairest single number for comparing bids of different sizes and tiers |
| First-year production estimate, kWh | Your figure | Your figure | Your figure | Ask what shade, soiling, and temperature losses the model assumed |
| Production per watt, kWh per W DC | Calculated | Calculated | Calculated | A high outlier on the same roof usually means an optimistic shade model, not better panels |
| Savings assumptions: rate escalation, export rule, degradation, horizon | Your figure | Your figure | Your figure | Small changes in any of these swing payback by years; re-run all three with one conservative set |
| Warranties: product, performance, workmanship, years | Your figure | Your figure | Your figure | The workmanship term tells you how long the installer expects to be around to honor it |
| Installer: years under current name, own crews or subcontractors, license holder | Your figure | Your figure | Your figure | Subcontracted labor changes who climbs the roof when a penetration leaks |
| Contract terms: production guarantee, roof leak clause, milestone timeline, interconnection responsibility | Yes, no, or unclear | Yes, no, or unclear | Yes, no, or unclear | Remedies written into the contract matter more than promises made at the kitchen table |
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Also from Solarholm
- Home Solar Pre-Signing Checklist: A step-by-step checklist that walks a homeowner from the utility data and roof survey through panel, inverter, and battery choices, the savings assumptions, the installer, and the contract, so nothing important is left to trust on signing day.
- Free calculators