Before you read
Version 1.0 draft · October 2026. This reading edition is adapted from BidProof’s draft disclosure standard. It describes what a proposal should show a homeowner before signing; it is not a certification, a guarantee of a fair deal, or a list of everything BidProof currently verifies.
The paper is for homeowners comparing bids and for installers, sales organizations, proposal-software makers, lenders and lease providers preparing them. Use the specification tables to examine the document, or start with the kitchen-table checklist.
Some items are recommended practice. A missing detail is a reason to ask a question, not proof that an installer is dishonest. A fully disclosed proposal can still be overpriced, oversized or a poor fit.
Five principles
Every part of the standard follows the same disclosure principles.
- Disclosure, not judgment. State the facts without setting price targets, grading thresholds or preferred equipment.
- Label assumptions. Estimates of production, utility rates, incentives and savings need a source and a method.
- One figure, one basis. State units and distinguish DC from AC, year one from lifetime, and costs before incentives from costs after them.
- Say what does not apply. “No battery included” and “No dealer fee” tell the homeowner more than silence.
- Keep the contract consistent. Carry each figure and term into the contract, or show and explain what changed.
1. Who you are buying from
Before anything else, the homeowner should know which company is legally responsible for the work and be able to look it up with their state licensing board.
| Item | How to state it |
|---|---|
| Legal company name | The registered business name of the selling company, not only a brand, logo, or trade name. |
| Contractor license | The license number and the issuing state, printed on the proposal itself, not only on the contract signed later. |
| Contractor of record | The company that will pull the permit and perform the installation. If any of the work is subcontracted, the subcontractor’s name and license number. |
| Salesperson (recommended practice) | The name and contact details of the person presenting the proposal. |
| Proposal date and validity (recommended practice) | The date the proposal was prepared and how long its pricing holds. |
2. What you are buying
Exact equipment names are what make a proposal checkable. “Premium panels” cannot be looked up. A manufacturer and model number can.
| Item | How to state it |
|---|---|
| Panels | Manufacturer, full model number, rated wattage at standard test conditions (STC), and quantity. |
| System size | The DC nameplate size, calculated as panel quantity × rated wattage, labeled “DC.” Any AC or CEC-AC rating stated separately and labeled as such. |
| Inverters | Manufacturer, model, quantity, and type (microinverter, string inverter, or hybrid). |
| Battery, if any | Manufacturer, model, quantity, usable capacity in kWh (not total capacity), and continuous power rating in kW. If no battery is included, the proposal says so. |
| Substitution rule | If equipment may change before installation, the rule that governs it: for example, equal or higher rating, with the homeowner’s written approval. “Or equivalent” with no rule gives the homeowner nothing to hold. |
3. What it will produce
The production estimate anchors every savings figure that follows. If it is high, the payback, the offset, and the lifetime savings are all high with it.
A proposal does not need to print every engineering input behind the estimate. It does need to show the design the estimate was built from, so anyone can check that the estimate fits the roof.
| Item | How to state it |
|---|---|
| Roof layout | A drawing or image of the actual design: which roof planes, or which ground area, hold the panels, and how many sit on each. The production estimate is built from this design, not from a generic system of the same size. |
| Year-one production | Expected annual output in kWh for the first full year of operation. |
| Modeling method | The software or model used to produce the estimate, and the weather data behind it. |
| Shading loss | The annual shading loss assumed, as a percentage, and how it was determined: on-site measurement, an imagery-based tool, or an assumption. |
| Degradation (recommended practice) | The annual decline in output assumed over the life of the system. |
| Usage offset | The share of the household’s annual electricity use the system is expected to cover, and the usage figure that share is based on (twelve months of bills, or an estimate, and which). |
4. What it costs
For a cash or loan purchase, show the price before incentives and name every added cost. For a lease or power purchase agreement, make the ownership structure and payment obligations clear so the homeowner can compare like with like.
| Item | How to state it |
|---|---|
| Total price | The full price in dollars, before any incentive, rebate, or tax credit. |
| Price per watt | The total price divided by the DC nameplate size in watts, so proposals of different sizes can be compared. |
| Itemized additions | Each addition with its own price: roof work, main electrical panel upgrade, trenching, battery, critter guards, monitoring, and anything else. |
| Cash and financed price | Both prices, if they differ. If a financed price includes a dealer fee, the fee’s amount. |
| Incentives | Each one listed separately: the program name, the agency or utility that administers it, the amount, who receives it (the homeowner or the system owner), and a statement that eligibility is the homeowner’s to confirm. An incentive is never subtracted from the price without that label. |
| Lease or PPA cost | Any upfront or prepaid amount, the first-year payment and total payments over the term with the escalator compounded. State who owns the system, who receives ownership-related incentives and which, if any, reach the homeowner. |
5. How the savings were calculated
A savings figure is the output of several assumptions multiplied together over many years. The homeowner should be able to see each one.
| Item | How to state it |
|---|---|
| Current usage and bill | Annual electricity use in kWh and what the household pays now, with the source: actual bills or an estimate. |
| Utility and rate plan | The utility’s name, the rate schedule the household is on, and the pre-solar rate used, in cents per kWh. |
| Post-solar rate plan | The rate plan the household will move to after installation, if different, and whether the move is required. |
| Export credit | How electricity sent to the grid will be credited (net metering at the retail rate, net billing at a lower export rate, or no credit) and the value used. |
| Utility rate escalator | The yearly increase assumed in the utility’s rates, as its own number. It is never combined with, or confused with, a lease or PPA payment escalator. |
| Analysis period | The number of years the savings cover, and whether figures are in today’s dollars or future dollars. |
| Payback and lifetime savings | The result, shown with the inputs that produced it, so the homeowner could rebuild it. |
6. How it is paid for
A loan and a lease are different agreements with different risks. The standard has a common part and a part for each.
For every agreement: the type of agreement (cash, loan, lease, power purchase agreement, or prepaid lease or PPA), named plainly at the top of the financing section.
| Item | How to state it |
|---|---|
| Loan · Lender and amount | The lender’s name and the amount financed. |
| Loan · Rate and term | The APR, the term in years, and the monthly payment. |
| Loan · Dealer fee | Whether a dealer fee applies, its amount or percentage, and that it is included in the amount financed. |
| Loan · Re-amortization | Whether the monthly payment rises if a lump sum is not paid by a set date, and if so, the amount, the date, and the payment both with and without it. |
| Loan · Prepayment | Whether the loan can be paid off early, and any penalty. |
| Loan · Total of payments | Every payment over the full term, added together. |
| Lease or PPA · Owner | The company that will own the system, and a plain statement that the homeowner will not. |
| Lease or PPA · Rate and term | The starting monthly payment or price per kWh, and the term in years. |
| Lease or PPA · Payment escalator | The yearly increase in the payment, as a percentage, and the year-one and final-year payment it produces. |
| Lease or PPA · Lifetime payments | Every payment over the full term, with the escalator compounded. |
| Lease or PPA · Production guarantee | What output is guaranteed, how it is measured, and what the homeowner receives if it is missed. |
| Lease or PPA · Buyout | Whether the homeowner can buy the system, when, and the price or formula. |
| Lease or PPA · Home sale | How the agreement transfers to a buyer, what the buyer must qualify for, and any fee. |
| Lease or PPA · End of term | The options when the term ends (renew, buy, or remove) and who pays for removal. |
7. Warranties, and who stands behind each one
A warranty is only as useful as the company that has to honor it. The standard asks for both the term and the name.
| Item | How to state it |
|---|---|
| Panel product warranty | Years of coverage against defects, and the manufacturer that provides it. |
| Panel performance warranty | Years of coverage, and the share of rated output guaranteed at the end. |
| Inverter and battery warranties | Years of coverage for each, and for a battery, the capacity or energy throughput guaranteed. |
| Workmanship warranty | Years of coverage for the installation itself, from the installer. |
| Roof warranty | Years of coverage for leaks at roof penetrations, and who provides it. |
| Who honors each | For every warranty above: the manufacturer, the installer, or the lease or PPA provider, and whether it is included or sold at added cost. |
| Lease and PPA obligations | What the provider must maintain and repair over the term. Any warranty sold separately on top of that is identified, so the homeowner is not paying twice for the same protection. |
8. The contract matches the proposal
Price, equipment, system size and financing terms should agree between the proposal and the contract. Show and explain each change. Ask which cancellation rights apply and how to exercise them; legal requirements depend on the agreement and jurisdiction.
| Item | How to state it |
|---|---|
| Same terms | Price, equipment, system size, and financing terms carry from the proposal into the contract unchanged, or any change is shown and explained. |
| Right to cancel | A written explanation of any cancellation rights that apply, how long they last, and how to exercise them. |
| Payment schedule | Payments tied to completed milestones, with the final payment due at permission to operate from the utility. |
| Permits and interconnection | Who is responsible for permits and for utility interconnection. |
| Changes | How changes to the work are approved and priced, and who pays for unexpected site conditions. |
| Disputes | Whether disputes go to arbitration, and whether the homeowner gives up the right to join a class action, stated plainly. |
A checklist for the kitchen table
Take these questions back to the person who prepared the proposal. Ask for missing details in writing.
- Who: The company’s legal name, license number and state, and who will actually do the installation.
- What: Exact panel, inverter, and battery model numbers. System size labeled DC. “No battery” stated if there is none.
- Production: A roof layout, year-one kWh, the shading loss assumed, and how shading was measured.
- Price: Purchase: total before incentives, price per watt, each addition priced. Lease or PPA: any upfront amount and the total of every payment.
- Incentives: Each one listed on its own, with who runs it and who receives it. None quietly subtracted.
- Savings: Your utility rate, the export credit, and the utility rate escalator, each stated as a number.
- Loan: APR, term, payment, dealer fee, and whether the payment rises if you miss a lump sum.
- Lease or PPA: Starting payment, escalator, final-year payment, buyout, home-sale transfer, end of term.
- Warranties: Each warranty’s length, and the company that has to honor it.
- Contract: Same terms as the proposal, written details of any cancellation rights that apply, and payments tied to finished work.
A few terms
| Term | Meaning |
|---|---|
| DC nameplate size | Panel quantity multiplied by each panel’s rated wattage. The standard way to state system size. |
| PVWatts | The public solar production calculator from the National Laboratory of the Rockies (formerly NREL), using location, system size and roof geometry. |
| Utility rate escalator | The yearly increase a proposal assumes in your utility’s rates. Different from a lease or PPA payment escalator. |
| Dealer fee | A fee a solar lender charges the installer, usually built into the price of the system. |
| Re-amortization | A loan clause that raises the monthly payment if a lump sum is not paid by a set date. |
| Contractor of record | The licensed company legally responsible for the installation. |
| Permission to operate | The utility’s approval to switch the system on. |
Limits and next steps
This is a disclosure standard, not a certification or an assurance of a good result. BidProof does not certify installers or proposals through this paper. The standard sets no grading thresholds and gives no guarantee of performance or savings.
It is not legal, tax, financial or engineering advice. Applicable law and the terms of the actual agreement govern. Confirm tax eligibility using current IRS guidance and a qualified adviser; ask an attorney about legal rights or contract effects.
BidProof’s review scope is described separately on the methodology page. A draft recommendation here does not mean a review independently verifies that item. In particular, checking whether a license number appears is different from confirming an active license with a state board.
This reading edition keeps the draft version and source month. Future revisions should identify what changed.