How We Audit Solar Proposals at Sunrun: A 5-Step Checklist for Quality Control

I'm the quality guy. Every proposal, contract, and system design that goes out to a Sunrun customer or a partner builder stops at my desk first. Over the last three years I've reviewed roughly 2,100 unique items. I've rejected around 12% of first drafts in 2024 alone—mostly because of spec mismatches or missing compliance language. Not because they were 'bad.' Because they weren't bulletproof.

For a residential solar installation—especially one bundled with battery storage and EV charging—the difference between a smooth closing and a costly fix is buried in the fine print. Small builders and property developers often don't have a dedicated quality check. They rely on their sales rep or the installation crew to catch problems. That's risky.

So here's the checklist I use. If you're a contractor, a small development firm, or a property manager vetting solar for the first time, run your next proposal through this before you sign or present it to a homeowner. It takes about 20 minutes and it's saved me from at least four disaster scenarios this year.

Step 1: Verify the Customer Profile Against the Hardware Specs

This sounds obvious but it's the most common miss. I can't tell you how many times I've reviewed a proposal where the system size or battery count doesn't match the customer's actual utility usage or site conditions.

Check three things:

1. Annual kWh usage — Was the customer's 12-month utility history loaded into the proposal? Or did the sales rep use an estimate? If there's no history, the proposal should state that clearly. Under-sizing a system to lower the sticker price is a fast way to get a complaint six months later.
2. Battery sizing — If they're adding a Tesla Powerwall or similar, does the backup load profile match? I've seen proposals where a single Powerwall is listed for a home with a 5-ton AC unit and a pool pump. That's not gonna work for whole-home backup unless the customer is okay with load shedding. Make sure the proposal says if partial or whole-home backup is assumed.
3. EV charger integration — If the customer has an electric vehicle or plans to get one, the proposal needs to account for that extra load. Don't assume the charger will be installed after the solar is live. It changes the consumption pattern.

Common trap: The proposal says "solar lease buyout option available in Year 6." Check if that language has a specific cost formula attached. If it's vague, ask. We've had partners sign deals thinking the buyout price was fixed when it was actually based on a fluctuating market rate. That's a $18,000 miscommunication waiting to happen.

Step 2: Confirm the Leasing vs. PPA Language is Clear and Compliant

Sunrun's model relies heavily on leasing and Power Purchase Agreements. That's a great tool for many homeowners, but the paperwork has to be tight. Per FTC guidelines (ftc.gov), terms must be truthful and not misleading. If the proposal says "$0 down" but buries the fact that there's a prepaid lease buyout option, that's a problem.

Check these clauses:

• Escalator rate — Many PPAs have an annual increase (usually 1.5% to 2.9%). This should be shown on the first page of the agreement. If it's buried in the fine print, flag it.
• Buyout terms — Is the buyout price fixed or formula-based? When can the customer exercise it? We rejected a batch of contracts in Q1 2024 because the buyout clause referenced "current market value" without a definition. That's a legal risk.
• Transferability — What happens if the homeowner sells the house? Most leases are transferable, but the new owner has to qualify. The proposal should state this clearly. We had three cancellations last year because the buyer refused to take over a lease they didn't understand.

Personal note: I ran a blind test with our sales team last year: same product, two different proposal formats. One had the lease terms summarized in a table on page two. The other buried them in the appendix. Over 80% of the test group said the summarized version was "more trustworthy." The cost of formatting change was a few hours of QA time. On our volume—roughly 50,000 proposals a year—that's an easy win.

Step 3: Validate the Site Survey Data Against the Permitting Requirements

This is where small builds get stuck. A proposal might look perfect on paper but fail when the city inspector walks the roof.

Check these variables:

1. Roof pitch and orientation — Is the proposed array actually viable on that roof face? We rejected a design in September because it placed 12 panels on a north-facing slope. The proposal software let it through because the algorithm didn't check orientation against local solar access laws.
2. Shading analysis — Does the proposal assume 100% sun? Or does it use a shade report from a third-party tool? If it's an estimate, it should say so. I've seen installations underperform by 28% because the shade study was done with a smartphone app in winter. Actual tree canopy matters.
3. Exclusion zones — Local fire codes require setback areas on roofs for access. They vary by jurisdiction. In Corona, CA, for example, you need a 3-foot clearance from the ridge. The proposal must reflect that or it's not permittable. We had to re-cost an order for $5,200 because of a code conflict in Temecula last year.

Source check: According to USPS business mail standards, an envelope must be no thicker than 0.25 inches for standard letter rates. Same logic applies here: if the panel layout doesn't fit the envelope of local code, the proposal is paper-thin. Verify local regulations at the building department's website—not just in the proposal software.

Step 4: Check the Equipment Serial Numbers and Warranty Transfers

Now we get into the nitty-gritty. I review roughly 200 unique proposal items annually, and this is where I find the most expensive errors.

• Panel and inverter model numbers — Are they actually current? Occasionally a proposal lists a panel model that's been discontinued or replaced by a newer SKU. The installer might still have old stock, but if the customer expects the newest spec and gets a legacy model, you've got a problem. I rejected a batch of 22 proposals in February because the listed inverter was an older model that didn't support the customer's battery topology.
• Warranty effective dates — If the solar is leased, the warranty is typically 25 years for panels and 10 for inverters. But if the system is sold outright, the warranty transfers to the new owner if the house sells. The proposal should state if the warranty is non-transferable. We had one case last year where a builder bought a system, sold the home, and the new owner claimed the warranty was invalid. That was a $22,000 redo.
• Battery cycle life — For storage products like the Powerwall, the warranty is usually 10 years or a certain number of cycles (e.g., 37.8 MWh throughput). The proposal should note whether the estimated annual cycling (based on the customer's usage) aligns with that. If they're expected to cycle the battery 300+ times a year, the warranty might run out faster than the homeowner expects.

Why this matters: The numbers said go with the cheaper battery cabinet from a third-party supplier—15% less. My gut said stick with Sunrun's standard supply chain because we'd already vetted that vendor's certification paperwork. I went with my gut. Later we discovered the cheaper vendor didn't have UL 9540A certification for their enclosure. That would have delayed permitting in three different fire jurisdictions. Saved myself a call to explain a delay—and probably a lost customer.

Step 5: Double Check the Financials—Especially the Incentives and Credits

This is the part customers actually read. And read carefully. A mistake here erodes trust faster than any hardware issue.

Verify three numbers:

1. Federal ITC (Investment Tax Credit) value — As of 2024, it's 30% for systems placed in service before 2033. But it applies to the gross cost of the system, not the net cost after rebates. If the proposal shows a $20,000 system with a "30% tax credit" listed as $6,000, that's correct. If the proposal subtracts the local rebate first and then applies 30%, the number is wrong. I've seen both. The difference on a $20,000 system with a $2,000 rebate is $600. That's not nothing to a homeowner.
2. State and local incentives — These change constantly. For example, California's NEM 3.0 drastically reduced export rates starting in April 2023. A proposal that still assumes 1:1 net metering is misleading. The proposal should reference the current rate structure. We insert a footnote on every California proposal: "NEM 3.0 applies. Actual savings vary." Source: California Public Utilities Commission (cpuc.ca.gov). Verify current rates there.
3. Total cost vs. financed cost — If the customer is financing the system, the proposal should show the cash price and the financed price separately. The difference is the cost of the loan (interest and fees). I saw a proposal where the financed price was listed as "$35,000" without mentioning that the cash price was $28,000. That's a $7,000 difference not clearly disclosed. That cost us a customer satisfaction score drop in Q3.

Pricing reality check: According to major online solar pricing databases, a typical 7kW system with battery storage in Southern California runs between $28,000 and $38,000 before incentives (as of January 2025). If a proposal is way below that range, ask why. It's probably missing a line item (like main panel upgrade) or using unverified hardware.

What to Do When a Proposal Passes This Checklist

If it passes all five steps, it's ready to present to the customer or submit for permitting. But don't stop there.

• Cross-check the home address — We once delivered a permit set to the right address but with the wrong AHJ (Authority Having Jurisdiction) stamped on the drawings. The city inspects in one jurisdiction; the county in another. We were in Somers county but used Austin city forms. That was an $800 redo and a three-day delay.
• Get a second set of eyes — Even on a good proposal, I ask a colleague to do a spot check on the financials. Fresh eyes catch things like a misplaced decimal or an expired rebate that I missed because I was focused on the hardware specs.
• Prepare the homeowner for what comes next — The proposal is step one. The homeowner should know that after signing, there's a site survey, then a permitting phase that can take 4-8 weeks depending on jurisdiction, then installation, then a final inspection. I've seen customers get cold feet during the permitting wait because they thought install happened in two weeks. Manage that expectation upfront.

Small client note: I've done this checklist for projects as small as a single-home battery add-on ($8,000 system) and as large as a 150-unit new build project. If you're a smaller builder or buying for your own home, don't let a sales rep tell you this level of review is only for big orders. Today's $8,000 customer might be tomorrow's $80,000 development partner. The vendors who treated my early orders with respect—reviewing my specs, answering my questions—are the ones I still call for my largest requests. Small doesn't mean unimportant. It means potential.

One last thing: Prices and incentive figures mentioned here are as of January 2025. Always verify current rates at usps.com/stamps for mailing references, cpuc.ca.gov for California solar policies, and ftc.gov for advertising compliance. The proposal you review today is built on data that may change in six months. That's why this checklist exists—to catch what slips through.