Compare your quotes on the same basis
Up to five proposals side by side, with a like-for-like score that never rewards a quote for staying vague — and the gaps listed as questions to ask.
Put your quotes side by side
Two to five proposals, compared on the same basis — with the gaps shown rather than filled in.
Leave a field blank if the quote genuinely does not say. Blank is never treated as zero — it is recorded as an unanswered question and left out of the like-for-like score.
What matters to you
Set a weight from 0 to 10. Zero switches a criterion off entirely.
Side by side
Where the score comes from
Each criterion is scaled from 0 to 10 across the quotes that supply it, then weighted. A blank cell contributes nothing and is excluded from the divisor, so it neither helps nor hurts.
What each quote does not say
Questions for each installer
How the score is calculated
For each criterion, the quotes that supply a value are scaled from 0 to 10 — best to worst, in whichever direction is better for that criterion. Those scaled values are multiplied by your weights and averaged.
Two scores are shown, and the second is the fair one. The like-for-like score uses only the criteria that every quote supplies, so nobody is rewarded for being vague. The own terms score uses whatever that quote happens to have, which is useful for seeing how a quote presents itself but is not a fair ranking.
A blank is never a zero. A quote that does not state a workmanship warranty is not offering zero years — it is leaving a question unanswered. Scoring it as zero would rank a candid two-year warranty below a silent one, which is exactly backwards.
Where quotes mix cash and financing, the price-per-watt figures are not directly comparable and the tool says so.
Why a score is the least useful thing here
The number at the top is the part to trust least. It reflects weights you chose, on the handful of things that happen to be numeric, from figures the installers chose to disclose. Nothing in it captures whether a company turns up when the inverter fails in year seven, which is the thing that actually determines whether you are happy with the decision.
The genuinely useful output is further down: the side-by-side rows, the list of what each quote leaves unsaid, and the questions to take back to each installer. A quote that is missing five figures is not necessarily worse — but you cannot compare it until those figures exist, and asking for them tells you something about how the company operates.
Compare cash to cash
If one quote is financed and another is not, the price per watt of the financed one includes the cost of borrowing and the other does not. They are not the same measurement. Ask every installer for a cash price, even if you intend to finance — it is the only way to see what the system itself costs, and it exposes a dealer fee built into the price rather than charged as interest.
What to weight heavily
Workmanship warranty, usually. Panels almost never fail, and when they do the manufacturer honours it. What fails is the installation — flashings, penetrations, conduit, connections — and the workmanship warranty is the only thing standing between you and paying twice. It also varies more between installers than anything else on the list, from two years to twenty-five, which makes it the most informative single number in most proposals.