If you already see the value solar provides and are ready to move forward, you likely now face the next big decision: Choosing the right provider through the solar proposals you receive. Here’s the thing. It’s not always apples to apples. Proposals can differ in scope, assumptions, and the level of detail, and that’s where things can either go smoothly or leave you scratching your head. Having worked on several home solar projects throughout Utah with Avail Solar (and having prepared many of those solar proposals myself), I wrote this article to walk you through exactly what a proposal should include. More importantly, I’ll point out which details you need to pay attention to so you can tell whether the offer in front of you truly fits your home and situation. After all, this isn’t a project that sits on your roof for a week, but one that’ll likely stay with your home for decades.
What’s Included in a Solar Proposal?
These are the key elements you should clearly look into once you receive a solar proposal.
System Size (kW)
System size, measured in kilowatts (kW), refers to the total power output your solar system can produce at full capacity. In most proposals, this will be one of the first numbers you see, often shown as something like “6.2 kW system.”
This number matters because it gives you a snapshot of how much electricity your system could generate, but it should ideally line up with your actual energy use at home. Too small, and you fall short. Too big, and you might be overspending for power you won’t use.
I wrote a separate guide on how to size your solar system. You can use it to check whether the system size listed in your proposal actually makes sense based on your household’s energy needs.
Estimated Annual Production (kWh)
Estimated annual production refers to the amount of electricity your solar system is expected to generate over a full year, expressed in kilowatt-hours (kWh).
Because it’s in the same unit as your utility bills, it’s easy to compare this number against your past energy use and see how well the system is expected to cover your needs.
Keep in mind that a thought-through solar proposal won’t just give you a single yearly estimate. It will usually include a month-by-month breakdown, either in table form or as a graph. This lets you see how your solar production might rise or dip throughout the year.
Even better, most proposals will show this production estimate right next to your own historical energy usage. That way, you can immediately see how well the system is expected to meet your actual needs (solar providers will usually ask for your recent utility data to do this).
It’s also fair to expect the proposal to clearly state what assumptions were used to come up with these numbers. That includes shading losses, orientation of your roof, and local weather patterns, among other things.
Project Site Layout
The project site layout is a visual representation of how your solar panels will be positioned on your roof (or elsewhere on your property), a bird’s-eye view showing where each panel will go, essentially.
If you look a bit deeper, this layout also shows surrounding buildings, trees, and other potential obstructions that may create shading, along with the direction your panels are facing, which also affects your production.
This matters because it gives you added context for the assumptions made earlier in the simulation used to estimate your annual production.
Estimated Savings, ROI, and Payback Period
A well-prepared proposal should show you the dollar outcomes clearly, because beyond the goal of cutting down carbon, solar is, first and foremost, an investment. That being said, you can expect to see:
- Estimated savings: Usually refer to how much you’ll avoid paying the utility over your panels’ lifespan (around 20 to 25 years). These are often shown in dollar amounts, either as a lump sum or year-over-year comparison.
- Payback period: Tells you how long it might take for your savings to equal the cost of your system, or essentially, when your system has paid for itself.
- Return on Investment (ROI): Gives you more financial lens to compare your solar system with other big-ticket investments, like home renovations or even stock market returns.
These often show up as tables, bar graphs, or line charts in your proposal, helping you see how your money moves over time.
On this note, it helps if the proposal also states upfront any assumptions about rising electricity costs, since even a small utility escalator can quietly shape how realistic those savings projections really are.
If you want to understand exactly how these numbers are calculated, I wrote a full article breaking down solar panel return on investment. It’ll hopefully help you do your own math to see whether the savings in your proposal are realistic or inflated.
Financing Options
Like many solar companies, we, at Avail Solar, work with trusted financing partners to make solar more accessible. Because let’s face it, solar isn’t exactly cheap by any means, and most homeowners need flexible options to make it work.
That’s why your proposal should clearly show:
- Who the financing provider is
- How many payments you’ll be making (and how often)
- The exact dollar amount per payment.
You’ll usually get a visual breakdown as well, a simple cash flow chart showing what you’re expected to pay over time and how that compares against projected savings.
Some proposals may also include options like solar leases or Power Purchase Agreements (PPAs), which sound great upfront since they often come with zero initial cost.
However, they could end up costing you more in the long run, especially because you won’t own the system. If you want the full picture, I wrote an article on how solar panel leasing works, where I also explain why, personally, I’m not a fan of these types of solar contracts.
Total Cost of Your System
The total cost of your solar system is, of course, a major detail. But don’t just stop at this headline figure.
You’ll want to check if the math includes solar incentives, like the 30% federal tax credit or any state/local programs, which can cut thousands off the final amount. These should be clearly stated in the proposal.
Another useful figure is cost per watt ($/W), which is one of the simplest ways to compare pricing across different offers. Some proposals leave it out, but you can calculate it yourself: Just divide the total system cost (before incentives) by the system size in watts.
Panel and Inverter Brands/Models
Imagine being promised premium, high-efficiency equipment in your proposal, only to find out later during installation that you’re getting something else entirely. It happens, and many times, it’s not even intentional.
That’s why it’s worth knowing exactly what equipment you’re getting upfront, especially since quality often isn’t broken down line by line, but rather rolled into the total system cost.
Panels on the higher end typically have higher efficiencies, stronger warranties, and better manufacturer backing. As for inverters, microinverters, string inverters, and hybrid setups each come with their own pros and tradeoffs.
If product data sheets aren’t included in the proposal, you can always request them directly from the solar provider. These documents give you a deeper look into the specs and certifications of the equipment being offered.
Warranties and Guarantees
Another item usually bundled into your total system cost is the warranty coverage, which is something you shouldn’t overlook, especially since solar is meant to last decades:
- Product warranties usually come from the panel and inverter manufacturers and cover defects in materials or workmanship. These often run for 10 to 25 years.
- Performance warranties guarantee that your solar panels will continue producing at a certain percentage (typically 80% or higher) of their original capacity by year 25.
- Workmanship warranties are offered by the installer and cover labor-related issues, like improper mounting or wiring mistakes. These vary by company but often range from 5 to 15 years.
If you want a deeper dive into what each of these warranties covers (and what they don’t), check out our full guide on solar panel warranties.
Project Scope
One area that often causes the most friction down the line is the project scope. This is the part that outlines what your installer is actually responsible for, and what they aren’t.
This matters because some of the biggest misunderstandings happen when homeowners think something is included, only to find out later it’s not. That’s where those “hidden cost” surprises often come from.
That said, here are a few key things your proposal should spell out clearly:
- Who handles what: Does your installer take care of solar permitting and HOA approvals? What about any fees tied to that? Will they assist with post-installation support, like monitoring setup or panel cleaning?
- Timeline expectations: What’s the estimated schedule for permitting, installation, and final grid interconnection? Delays can happen, sure, but your proposal should at least give you a baseline so you’re not left unclear when things will move forward.
- Aesthetic considerations: Did the installer take time to ask about your preferences? That could include choosing all-black modules, using conduit runs that are less visible, or adding array skirts to make your system blend in better from the curb.
Solar Company Details
Most proposals will include a quick blurb about the company offering the installation. That’s pretty much standard. But don’t just take those statements at face value, because what a company says about itself and what its customers experience can be two very different things.
That said, I always recommend doing your own research. And one of the best ways to do that is to give them a call. Ask direct questions and pay attention to how they respond. I put together a guide on questions to ask solar companies that you can use as a reference if you’re not sure where to start.
Solar Proposals Vary by Home
If your cousin in another state (or even just a few neighborhoods away) tells you they got solar for way less or with different equipment, don’t be surprised if your proposal looks nothing like theirs. Here are 5 reasons why no two solar proposals are the same:
- Electricity rates, annual inflation, and average sunlight hours differ by region, which means the same system in one state might produce more or less in another.
- Different installers may use different assumptions or tools in their simulations, which can lead to wide variations in projected energy production.
- Some panels are more efficient and degrade more slowly over time, but they may cost more upfront. What you’re quoted depends heavily on what you’re being offered.
- Some proposals include extras like batteries, monitoring, or extended warranties. Others leave these out or treat them as optional add-ons.
- Not all proposals are equally transparent. Some give you every number and assumption up front, while others bury critical details or gloss over them entirely.
If you already have a reference proposal from another installer, you can always bring it to your current provider. Avail Solar, for instance, will help walk you through the differences and explain whether there’s room to match the offer or if your system needs a different setup.
Get Solar Proposals That Match Your Needs
By now, you’ve seen what goes into a well-prepared solar proposal and how the real focus should be on how well the proposal fits your home, usage, and long-term goals, not just the price tag.
So before saying yes to anything, make sure you’ve asked the right questions, got a second opinion, and taken the time to really think it through.
And if you’re ready to request a quick proposal (or want something more competitive than what you already have), reach out to Avail Solar and request a quote today!