Vivint Solar Checklist: 7 Things I Check Before Approving a Solar Proposal

This checklist is for commercial property owners, facility managers, and corporate energy buyers who are looking at solar. If someone has handed you a proposal from Vivint Solar, a local installer, or any other brand, run it through these seven checks before you sign. It takes about 20 minutes and it will probably save you from a few expensive surprises.

I work on the quality side of solar. I review proposals before they reach customers—roughly 100 unique proposals a year. In 2024, I rejected 16 of the 104 proposals I reviewed—or rather, 16 came back for revisions. Some of those got approved later. This checklist is the same set of questions I use. Vivint Solar, backed by Sunrun's national scale, sells integrated solar panels, battery storage, backup generators, and EV charging infrastructure. I'm not here to sell you on that; I'm here to help you check any proposal before you sign.

One caveat: my experience is based on national vendors and mid-sized commercial projects. If you're working with a tiny local installer or a large utility-scale developer, your experience might differ.

The 7-Point Checklist

1. Pull up your current system documents

If you already have a Vivint Solar login, log in and download the original system design, monitoring data, and contract. After the Sunrun acquisition, that login may redirect to Sunrun's customer portal. That's normal. The important thing is that you're not working from memory.

If you're a facility manager handling a system you didn't buy, ask the property owner for the same documents. Checkpoint: you should be able to see the exact panel model, inverter model, and any battery model. If you can't, keep asking.

2. Check who gets the solar energy credits available for Vivint Solar customers

In my experience, this is the step that gets skipped until tax season. The solar energy credits available for Vivint Solar customers depend on one big thing: system ownership.

If you bought the system outright or financed it with a loan, you own it, so you can claim the federal Investment Tax Credit. According to Energy.gov, the residential clean energy credit is 30% for systems placed in service through 2032. For commercial projects, the rules are different. The commercial ITC under Internal Revenue Code Section 48 can be 30% if the project meets prevailing wage and apprenticeship requirements. Otherwise, the credit rate may be lower. If you sign a lease or a power purchase agreement, the system owner typically gets the tax credit; you get the agreed electricity rate instead.

State-level solar renewable energy credits and performance-based incentives are separate from the federal tax credit. Check DSIRE (dsireusa.org) before you bank on them.

3. Price the battery in real numbers

The question I get most often from buyers who want storage is: How much is Tesla Powerwall? As of early 2025, the installed price for a Tesla Powerwall 3 is usually around $12,000 to $16,000 before incentives, based on Tesla's website and typical installer quotes. That's per unit. Your actual quote will depend on labor, electrical work, and local permitting.

But price alone is not the spec that matters. Look at usable capacity, not just the label. A 13.5 kWh Powerwall won't deliver 13.5 kWh in every condition. Usable capacity changes with temperature, discharge rate, and the inverter limit. If a salesperson says one battery will run the whole building, ask for the load calculation. The better question is: What's the peak load I need to cover, and for how long? Then compare battery systems on cost per usable kilowatt-hour, not monthly payment.

4. Confirm the inverter specs before you approve

Inverter quality is where I'm pickiest. The proposal should state whether you're getting a string inverter, microinverters, power optimizers, or a hybrid inverter. It should also state the continuous power output, not just the peak number. If you plan to add EV charging infrastructure or batteries later, the inverter needs to support that.

In one 2024 audit, I rejected a batch of proposals because the inverter model was missing. The vendor said it was standard practice. It wasn't. Missing inverter specs usually means the sales process isn't ready for scrutiny. Ask for the inverter's UL 1741 listing as well. UL 1741 is the safety standard for inverters in North America, and your local authority having jurisdiction may reject the permit if the paperwork doesn't show compliance.

5. Don't confuse a backup battery with a portable inverter

This one catches people who are new to solar. A Foval 150W power inverter is a small 12V unit that plugs into a car outlet; it's fine for a laptop or a phone charger, nothing more. A Bestek 300W pure sine wave power inverter is a step up because pure sine wave output is cleaner for sensitive electronics. But if you're reading Bestek 300W pure sine wave power inverter reviews, you're probably looking for emergency power, not whole-building backup.

These small inverters don't store energy. They only convert DC to AC. In an outage, a portable inverter needs a separate battery source, and its continuous wattage limit is a hard limit. A 300W unit will not run a 500W load, period. Use them for routers, laptops, small tools, and communication gear. Not for a furnace, elevator, or security system.

Some buyers assume a portable inverter can plug into their solar battery. Usually, it can't. If you're adding a portable inverter as an emergency layer, plan it as a separate line item.

6. Compare total cost per kWh, not monthly payment

B2B buyers get attached to a monthly payment number. A proposal that says $400 per month may include tax credits, SREC sales, operating costs, and an escalator. The real cost per kilowatt-hour depends on system production over 20 or 25 years, financing costs, maintenance, and the price you would have paid for grid power anyway.

The monthly payment is not the full number. In Q3 2024, I compared four bids for an identical 250 kW system and found more than a 40% spread in the levelized cost per kWh. Same roof, same production estimate, different pricing. Get at least three bids and put them on a per-kWh basis before you compare.

7. Read the degradation and performance clauses

This is the least glamorous step and the one that costs people the most money.

Solar panels degrade over time, but the rate matters. A standard panel might have a 0.45% to 0.55% annual degradation rate, which means after 25 years it should still produce roughly 85-90% of its original output. Batteries degrade faster, and their warranties often exclude certain usage patterns, like repeated full discharges in high temperatures.

The contract should state:

• the guaranteed production in year one
• the degradation rate used in the performance projection
• the battery throughput warranty in megawatt-hours or cycles, not just years
• what happens if production falls below the guarantee

If a warranty uses vague terms like normal wear, ask for a definition. In 2022, I implemented a performance-clause check in our review process. Since then, warranty-related disputes in my portfolio dropped by about a third. I'm not sure if the clause itself prevented the problems or the vendors just started paying attention.

Common mistakes in solar proposals

• Assuming the same solar energy credits available for Vivint Solar customers apply to every customer. Ownership and tax status determine eligibility.
• Focusing on battery capacity but ignoring the inverter's continuous power rating.
• Buying a portable inverter like the Bestek 300W and expecting it to work as emergency backup for a whole building.
• Comparing quotes by price per watt without verifying the same production assumptions.
• Forgetting to log into the current customer portal to check monitoring data before signing a service renewal.

Bottom line

An informed customer asks better questions and makes faster decisions. I'd rather spend 20 minutes explaining this now than deal with a mismatched expectation in year three. Solar buying doesn't need to be confusing, but it does need to be boring about specs.

If you're considering Vivint Solar, use your customer login to pull the actual system documents. Ask who owns the credits. Price the battery in real dollars. Confirm the inverter spec. Separate backup layers. Compare cost per kWh. Read the degradation clause. That's the whole checklist.

Prices and incentives change. Verify current rates with Tesla, your installer, and official government sources before you sign.