A solar proposal is the document a company gives you after it has looked at your roof and your usage: a system design, a price, and a projection of what the system will save you. It is engineering and sales in one file, which is why reading it well means knowing which parts are measurements and which parts are assumptions.
Proposals are laid out differently by every company, but they carry the same sections in roughly the same order. Below is what each one tells you and the question that belongs next to it. No figures appear here on purpose: yours are in your own document.
What each section of a proposal means
The company block at the top
The legal entity proposing to do the work, which is not always the brand on the cover page or the crew that will arrive.
What to check. Match the entity name against the license you were given and against the contract later. Three names across three documents is worth a question.
System size
The combined rating of the panels, in kilowatts. It describes the equipment, not the electricity you will get out of it.
What to check. Ask why that size. The reasoning should start from your own twelve months of usage rather than a share of your bill chosen in advance.
The equipment list
Which panels and which inverter, by manufacturer and model, plus racking, monitoring and any storage.
What to check. Model numbers, not grades. A proposal that names a tier instead of a product leaves the company free to fit something else on install day.
The array layout
A roof drawing showing where panels sit, which faces they use, and how the rows are arranged.
What to check. Compare it with what you can see from the yard. Panels drawn onto a face you know is shaded after lunch are a modeling error you can catch for free.
First-year production estimate
How many kilowatt-hours the design is expected to make in year one, from a modeling tool fed with your location, orientation, tilt and shading.
What to check. Ask which tool produced it and what shading data went in. Two quotes for one roof should not disagree much; when they do, one of them has assumed away a tree.
Total price and price per watt
What you pay, and that figure divided by system size, which is the only way to compare two differently sized systems.
What to check. Check whether each quote calculates price per watt before or after incentives. Mixing the two conventions makes the cheaper system look dearer.
The incentives line
Any credit, rebate or program the proposal is counting on, and whether it has already been subtracted from the price shown.
What to check. Ask for the program named, its current status in writing, and the price with and without it. Whether you qualify is a question for your tax advisor, not the salesperson.
Financing terms
Whether this is cash, a loan, a lease or a power purchase agreement, and the payment schedule that goes with it.
What to check. Find the term length, the rate, any fee folded into the price, and whether the payment steps up later. A low opening payment can be a schedule rather than a discount.
The savings projection
A long-range comparison between what you would pay for power without the system and what you would pay with it.
What to check. Every figure in it rests on assumptions listed further down this page. Read those before you read the total.
Warranties
Separate promises covering the panels, the inverter, the workmanship and the roof penetrations, usually from different parties.
What to check. Get each one written with its term and the company that honors it. A single line reading full coverage names nobody and binds nobody.
Scope of work and exclusions
What the price includes, and the work it explicitly does not.
What to check. Tree trimming, roof repair, an electrical panel upgrade and trenching are the usual exclusions. Ask what each would cost if it turns out to be needed.
Timeline and milestones
The path from signature through design, permit, installation, inspection and utility approval.
What to check. Ask which steps the company controls and which it waits on. A promised switch-on date that depends on someone else is a hope, not a commitment.
The signature page
What you are agreeing to, which may reference terms held in a separate document.
What to check. Read everything it refers to before signing, at your own table.
The assumptions holding up the savings figure
The number at the bottom of a proposal is arithmetic performed on four inputs, and small changes to any of them move it a long way. Find all four before you take the total seriously.
- The electricity price increase. The projection assumes your power gets more expensive every year at some rate. That rate is a choice made by whoever built the model. Ask what it is, and compare it against what your own statements have done.
- The production estimate. Everything downstream is multiplied by it, so an optimistic shading assumption inflates the whole projection.
- Panel output over time. Panels produce slightly less each year. Ask whether the model accounts for that or holds year one constant for the whole term.
- What happens to exported power. The value of electricity you send out rather than use yourself depends on the program your utility operates and on the rules in force when you connect. Ask which arrangement the model assumed.
Putting two proposals side by side
- Write both system sizes and both total prices down, then calculate price per watt for each yourself, using the same convention for both.
- Line the equipment up by model. Different panels and different inverters are a real difference in what you are buying, not a rounding error.
- Compare the first-year production estimates. A large gap for the same roof means the two companies modeled your shade differently, and one of them is wrong.
- Compare the warranty tables promise by promise, noting who honors each one.
- Restate both savings projections using the same electricity price increase, then look again. Proposals often separate on this assumption alone.
- List the exclusions from both. The cheaper quote is sometimes the one that left more work outside the price.
A proposal is not yet a contract
The proposal shows a design and a price. The contract is the agreement that binds you, and the two are not automatically the same. Ask for the full contract to read at home, then check clause by clause that the equipment, the price, the schedule and the warranty terms carried over intact.
Before the proposals arrive, the installer questions checklist covers what to establish in the appointment itself. If a line in your own document is unclear, Solar Mike AI will work through it with the reasoning shown rather than handing you a verdict, and homeowners in the USA.SOLAR community post the questions their proposals raised and what the answers turned out to be.
Questions about solar proposals and quotes
What should be included in a solar proposal?
The system size, the equipment by manufacturer and model, an array layout, a first-year production estimate with its assumptions, the total price, the payment or financing terms, every warranty with the party honoring it, the scope of work with exclusions named, and a project timeline.
What is price per watt on a solar quote?
The total price divided by the system size in watts. It is the only figure that lets you compare two differently sized systems on the same basis. Confirm both quotes calculate it the same way, before or after incentives, or the comparison quietly falls apart.
How do I know whether a solar quote is fair?
By putting it next to at least one other quote for the same house, normalized to price per watt, and by checking that the equipment, the production estimate and the warranty terms are genuinely comparable. A single quote gives you no way to tell fair from unfair.
Is a solar proposal the same thing as a contract?
No. A proposal presents a design and a price; the contract is what binds both sides. Ask for the full contract before you sign anything, and check that the equipment, price, timeline and warranty terms in it match what the proposal showed you.