20 point checklist for comparing solar quotes

Now that you’ve gotten proposals from solar installers, how do you select which one is best for you? This article will guide you through the decision procress.

— by The Solar Nerd — About a 11 minute read.

If you’re actively in the process of getting solar panels for your home, at some point you’ll find yourself with a handful of proposals from solar installers, trying to decide between them.

Hopefully you used The Solar Nerd to find your contractors, which takes care of one of the most important steps in the process, which is getting multiple quotes and screening out underqualified companies.

Solar quotes can be several pages long with some dense contract language, so wading through three or four quotes (or more) can be a little intimidating. And even after rebates, it’s a pretty big purchase, so you might be scared of making a bad decision. How do you choose?

Use a checklist. This is the best way of managing any major home renovation, and a solar installation really isn’t any different. If you read our /guide/how-to-pick-a-solar-company/, you’ll already be familiar with a lot of the items we list here. If you haven’t read it, start there first.

The Solar Quote Evaluation Checklist

1. Do your background check on the company

For every quote you receive, make sure to do some due diligence on the company. If you used The Solar Nerd to get your quotes, we’ve already done this quality screening for you. If you used another service or found the companies yourself, make sure you do at least this:

  1. Find out if licensing is required to do solar installations in your state or municipality. Not all states issue contractor’s licenses, so you will need to look this up. The Interstate Renewable Energy Council maintains a web page where you can look up licensing requirements for your state. If a license is required, ask for their license number beause some states, like California, allow you to verify licenses online. This check may also tell you how long the company has been in business with a valid license.
  2. Ask if any of their installers are NABCEP board certified. This is an optional industry license, but it’s a credential that better installers will have.
  3. Check the Better Business Bureau. Many decent companies simply won’t have any reviews on BBB, which is fine. BBB is different from review sites because it’s intended to resolve complaints, and not serve as a forum for general reviews. Just be sure that there are no unresolved issues listed.
  4. Check review sites. Be careful to avoid solar review and contractor review sites, which have a history of pay-for-placement. We think that Yelp and Google reviews tend to be more trustworthy.

2. Make sure that you’ve met the company in person

Nobody likes persistent phone calls and voicemail from sales people, so some companies are trying to avoid that by making solar quotes an online-only marketplace. Don’t do that. It’s critical that an installer comes to your home to make an in-person technical assessment. Without that, there is no way for them to properly assess whether there are hidden roofing, electrical or building issues that could affect the installation.

You don’t want to be surprised in the middle of the job when your cost goes up by hundreds or thousands of dollars because of issues that weren’t discovered earlier. Insist on getting in-person quotes.

3. Discuss the equipment selection. Ensure it’s spelled out in the contract.

If you’ve read through our guide, you’ll know how important equipment selection is to your satisfaction with the system. The inverter is one of the most important system components, so make sure that you know the difference between string inverters, power optimizers, and microinverters.

Make sure that all the equipment is listed by manufacturer and model number. You want to avoid a situation where one type of equipment is discussed with the contractor, only to end up with something else getting installed.

4. Make your requirements clear to the installer

Every good solar installer wants to design a system that leaves you as a happy customer. In order to do that, you have to make sure that they know what’s most important to you. Are aesthetics very important? If so, you may want to pay a little more to get better-looking solar panels. Or maybe you’re looking to buy American-made panels. Or perhaps you’re expecting your PV system to keep the lights on during blackout, in which case you should be talking about a battery system.

Whatever the case, no contractor is a mind-reader, so when you meet with them in person, be sure to make your desires known.

5. Make sure the contract has a line-by-line cost breakdown

You want the contract to spell out the individual costs of the photovoltaic modules, inverters, racking system, electrical work, labor costs, and soft costs like engineering and permitting. Without a detailed breakdown, you’ll have an impossible time trying to make an apples-to-apples comparison between different proposals.

6. Compare the different equipment choices

Make sure that you have a clear expectation about how much power you would like your solar panels to generate in an average year. Whether you are looking to generate 100% of your electricity or only 50%, this is one of the most important points to discuss so that your installer can select the appropriate equipment.

Inevitably, different installers will recommend different equipment. This is because they will have relationships with different suppliers, may have equipment in their warehouse that they want to move, or have worked with certain brands in the past that they have a positive experience with.

For each proposal, ask the company why they recommend the equipment they do, and don’t be afraid to push back on any choice that you’re not comfortable with.

7. Figure out where the difference in costs are

Once you have a line item breakdown, you’ll be able to compare the different proposals and see where some companies may have higher costs than others. Is one company charging more for similar equipment? Is their labor cost higher? Do they recommend using different inverters? You won’t be able to do this analysis if the costs aren’t broken out, so insist on this in your proposal.

Of course, lower costs are not necessarily better. It may mean that a company is cutting costs where you don’t want to - for example, one company may do an ugly job of running dangling wires outside your house, while another company takes the extra step of neatly running conduit or hiding wires by pulling them through walls. You won’t know unless you ask.

8. Save money in the right place

Interestingly, if you want to cut costs on your solar system, the best place to do that is often the solar panels rather than other components. A high end panel might cost twice as much as a cheap one, but the performance-per-dollar almost certainly won’t be twice as good.

Unless you are very limited in the amount of roof space you have, it’s often a good tradeoff to save money by going with a lower efficiency panel and sacrificing a little more roof space. Solar panels have no moving parts, so even cheap panels have low failure rates. That said, some premium panels such as the LG NeON 2 series have excellent warranties that include labor, so if you place a premium on worry-free ownership, the cost premium might be worth it to you.

9. Understand the warranty terms

Every piece of equipment will have its own warranty: the solar modules, inverters, and racking system.

The solar installer will provide their own warranty, so be sure to understand what it covers. Know what the process is for making a warranty claim. Also find out if the solar panel warranty includes labor, because most don’t.

If component failures happen after the installer’s warranty, ask about the process for making a manufacturer warranty claim and having the component replaced. Ask what the labor costs will be if a failure happens outside of the warranty period. (Although labor rates will have risen if you’re dealing with a failure 20 years from now!)

10. Review the power production estimate

Your proposal will include an estimated power production output in kilowatt hours. Compare this to your expected power generation and make sure that you’re getting what you asked for. Hopefully you’ve studied your electric bill and have a good idea of what your real usage is.

If the real system output significantly underperforms the estimate, this should be covered by the installer’s warranty. Be sure to check.

11. Net metering

It’s critical to understand whether net metering is available to you. Even in states where net metering is mandated, there often exist maximum caps, and your utility may have exceeded that cap. So make sure that your installer explains whether you have a net metering or net billing arrangement with your utility.

12. Utility work

Related to net metering is the type of electric meter that will be installed by the utility company. Ordinary meters can’t track two-way flow, so the company will either replace your meter with a smart meter that can track both your usage and the electricity you send back into the grid, or add a second meter that only tracks power you send into the grid. Which method the utility will use mostly depends on whether you are under net metering or net billing.

Either way, find out from your installer, and make sure they let you know when the work to install the meter will be scheduled and if someone needs to be home.

Some utilities charge a fee for this meter installation. If it is, make sure it’s spelled out in the contract.

If you live in states with Solar Renewable Energy Credits, you may need a revenue grade electric meter to participate in the SREC market. See the Incentives section below.

13. Inspections

In addition to replacing the meter, other inspections or site visits that may be required are a visit from a structural engineer to make sure that your roof can support the additional weight of solar panels and racking, an electrical inspection from the city, or a final inspection by the utility company before they will let you turn on the system.

Which of these is required depends on your local codes, so make sure that the installer explains what is required and the timeline of these visits.

14. Review the system design

Your proposal should include a diagram of exactly where on the roof your solar panels will go, where the inverter will be, and how the wiring from the roof will be run down to the inverter and the panel.

This last detail is often overlooked, and if done unprofessionally can result in ugly cable runs in places where you don’t want, such as a part of the house that is visible from the street. If you don’t want the wiring showing on the exterior of the house, let the installer know. They may be able to run the wiring through the attic and down a wall cavity.

15. Contractor’s insurance

The installer’s contract should state that the company is covered by liability insurance and workers compensation insurance. Liability insurance protects you if any damage occurs to your house as a result of work done by the contractor, while worker‘s compensation insurance protects you if workers are injured while working on your property. Hiring any type of contractor, including a solar installer, that does not have these types of insurance is risky and could be very costly to you.

16. Payment terms and schedule

Whether you are paying cash or arranged financing through the contractor, be sure that you understand the payment terms. The contract will spell out when full payment is due or, if you are financing, the payment schedule.

17. Monitoring

Knowing how much solar power you are generating is a key part of owning a solar system, so make sure that you know what type of monitoring system you will be getting. Often this is a web page or smartphone app, but sometimes it’s as simple as a readout on the inverter. Depending on the inverter model, smartphone monitoring might be an additional cost, so make sure that you understand this from the installer.

18. Maintenance

Solar panels require minimal maintenance. If you are getting a lease or PPA, check the contract to see how system failures are monitored and handled. You don’t want to experience weeks or months of system downtime, so make sure this is spelled out. Also, under a PPA, see if regular cleaning is part of their service.

19. Incentives

Some state or local incentives are applied for by the contractor but returned back to you. For example, in New York state, the NY-Sun incentive is applied for by the installer, but is used to reduce the net cost you pay. Check our solar calculator to find out about incentives, and then follow up with your installer to find out how they work.

A few states have significant incentives in the form Solar Renewable Energy Credits (SRECs), which are bought and sold on an open market. If you are in one of these states, find out from the solar installer what the latest status is, what the requirements are, and what the best way for you sell your credits are.

20. Review your timeline

Once you’ve gotten to the bottom of the proposal and asked all of your questions, you should have a pretty good idea of what the overall timeline of your project is, but it’s always a good idea to take another couple minutes to just jot it all down so that you have a clear picture of what the steps are, including inspections, installation, utility connection, and the all-clear from the utility company to switch your system on.

Buying Solar For Your Home: The Complete Guide

This article is part of a series to help the homeowner go solar.