How to Put Solar Panels on Your Roof: A Step-by-Step Guide

Rooftop solar is not like other types of consumer technology. Even though the end result is having a bunch of electrical equipment installed on the roof of your home, the process of getting solar is more like doing a bathroom renovation than buying a flat screen TV. To get the results you’re looking for, the most important decisions you’ll make are not the brand or model of the panels, but rather who you hire for the job, the size of your system, and how you finance it.

There’s a bunch more choices you’ll have to navigate along the way, and it’s easy to get overwhelmed. One expert I spoke with told me that sometimes the customers who are the most excited about getting solar end up bailing, the victims of decision fatigue.

We created this guide to save you from that fate. So take a deep breath, take my hand, and let’s walk down the metaphorical hardware store aisle and get you the rooftop solar solution you’re dreaming of.

THE EXPERT PANEL

Roger Horowitz is the director of Go Solar programs at Solar United Neighbors, a national nonprofit that serves as an unbiased resource for homeowners interested in solar. Horowitz manages and provides technical support to the company’s Solar Help Desk team.

Tony Vernetti is a senior trainer at Enphase Energy, a company that produces inverters, batteries, and EV chargers, where he trains solar sales and installation teams. Before joining Enphase in 2020, Vernetti spent 12 years working for rooftop solar companies in California.

Nate Bowieis the vice president of residential sales at ReVision Energy, an employee-owned solar company operating throughout northern New England. Bowie has been selling solar for ReVision for 15 years.

OVERVIEW OF THE PROCESS

• Finding your energy usage data and consider your financing options.
• Reach out to solar companies for quotes.
• Review and compare quotes and refine your system specifications.
• Secure financing and sign your contract.
• Wait for your installer to secure permitting and interconnection approvals.
• Schedule installation.

THE BASICS

• Photovoltaic panels convert sunlight into electricity. They come in different sizes and levels of efficiency.
  
• Solar panel size is expressed in watts, which is a measure of how much power each panel can generate in direct sunlight. The system size is expressed in kilowatts. (1 kw = 1,000 watts.)

• When you receive a quote, you will also see an estimate for how much power the system is expected to produce over the course of a year. This will be expressed in kilowatt hours. (1 kilowatt hour means your panel has generated 1 kilowatt for 1 hour.)
• Inverters are a key component of the system that convert the electricity the solar panels generate from direct current (DC power) to alternating current (AC power), which is the kind you use in your home. They are often called the “brain of the system” because they also collect data on system performance and send it to your monitoring system, an app you can use to track your energy production and system status.
• A battery, or energy storage system, is an optional component that can store the electricity your solar panels generate and dispatch it later. You can have rooftop solar with or without a battery, but your solar panels will not provide backup power during a blackout unless you have a battery. Most people get batteries for resilience during an outage, but in some regions with favorable policies, batteries can provide additional financial savings.
• Net metering is a policy that allows homeowners to sell excess power that their solar panels generate to their utility. The rate at which homeowners are compensated varies in every state, and can determine whether it is worth it to invest in solar, and how quickly the payback period is.

FREQUENTLY ASKED QUESTIONS

1. Is solar energy free?

When you start searching for information about solar on the internet, you might come across advertisements or commercials promoting free solar panels. There is no such thing. These ads are typically schemes to collect your personal data and sell it to solar companies looking for leads, and the federal government is starting to crack down on them.

It is possible to install solar with zero up-front costs if you lease the system or take out a loan to finance it, but in both cases you will still owe monthly payments. It is also rare that anyone is able to offset 100% of their utility bill. You can get close, but you will likely still owe at least a connection fee to your utility company.

2. I don’t live in the sun belt and my roof doesn’t face south. Is solar still worth it?

Most homeowners in the U.S. can benefit from installing solar as long as local energy policies are favorable. Placing the panels on a south-facing roof is optimal, but not necessary. If your panels face due west, you’ll only lose about 10% of potential generation, according to Vernetti. “They still produce a ton of energy. They’re still very effective. It's just a little bit less than if they're facing south,” he said. An east-facing roof is also viable in most cases.

3. Does having rooftop solar require me to do anything?

You don’t have to worry about shoveling snow off the roof or anything like that. But like any other electronic devices, solar panels, inverters, and batteries can break or malfunction, and your system may require servicing at some point. Pay close attention to your warranties (more on that later). If you lease the system, you do not have to worry about this as much because the third-party owner will be responsible for maintenance.

BEFORE YOU GET STARTED

1. Know your energy consumption history

In order to design a system that meets your needs and budget, solar companies will ask for a copy of your most recent electricity bill or, ideally, your annual energy consumption history. Make sure you have this information handy before you reach out for quotes.

2. Consider leasing versus owning

In most of the U.S., you will find you have the option either to lease your solar panels or buy them outright. You don’t have to decide which way you want to go before you get started, but it’s helpful to think through the pros and cons of each.

3. Learn about incentives

The federal government offers a 30% tax credit for solar installations (and batteries) that covers parts and labor. It can significantly reduce the cost of getting solar, even if you don’t have a lot of tax liability in the year that you install the system. The credit will roll over to subsequent tax years.

Additional tax credits and rebates may also be offered by your state energy office, city, or utility. Contractors should be able to help you figure out what you’re eligible for, and you can wait to talk to them to learn more. However, incentives change frequently, and contractors don’t always keep up, so you might want to review the options in your area independently.

It will also be helpful to understand your state’s net metering policy, as that will determine how quickly your investment in solar will pay off and may also dictate how big your system can be. Some states, like New Jersey, also allow homeowners to generate additional income through the sale of solar renewable energy credits, or SRECS.

Where to look for more information:

• The Database of State Incentives for Renewables & Efficiency is a great place to start, although it may not list county- or city-specific subsidies. Enter your zip code and filter the results by “Eligible Sector > Residential.”
  
• Check with your state energy office or local sustainability office. They may have a helpline, or have information about upcoming webinars or in-person educational events.
• The Solar United Neighbors Help Desk can also help you find and understand local incentives.

4. Find out how old your roof is

One of the worst things that could happen is you install rooftop solar panels, and then later find out you have a leak or some other problem with your roof. “Removal and replacement of an array for a reroof is expensive and could significantly impact the owner’s return on investment,” Bowie told me. While metal roofs last a very long time and are unlikely to need a replacement, asphalt shingle roofs generally have a useful life of 25 to 30 years, Bowie said. You should be fine if your roof is less than 10 years old, but if not, you may need some roofing work done before your solar panels are installed.

If you don’t know how old your roof is, Vernetti recommended having a roofing contractor inspect it. He added that there’s varying opinions on this, with some solar experts recommending replacement if the roof is only 5 years old. “In my opinion, scrapping a 5 year old roof is wasteful and goes against the goal of sustainability,” he said.

“A good solar contractor will help evaluate the roof conditions and should recommend replacement when necessary, even if it is just to replace the roof on the roof plane where the solar panels will go,” said Bowie.

FINDING A CONTRACTOR

Solar contractors range from local mom and pop shops, to regional providers like ReVision Energy, which operates in multiple states in the Northeast, to national companies that install across the country like Sunrun and Sunnova.

“The advantage of going with a large company is that they have the ability to offer financing the smaller companies might not be able to. With a regional company, you can actually walk to their office and knock on the door and talk to somebody if you want to,” said Vernetti.

Heatmap Recommends: Contact at least one local company and one national company to get a good sense of your options. Always get at least three quotes!

Here are a few strategies for finding solar contractors, in order of what we recommend:

• Talk to your friends, family, and neighbors that have solar. Were they happy with their experience? Which companies did they talk to? Who did they decide to work with and why?
  
• Check if your state energy office or utility has an online directory of local solar installers. If your town or city has a sustainability office, try that, too.
• Try using EnergySage, which will have you enter your address and monthly energy usage and then source quotes for you from installers that serve your area. (Note: Treat these quotes as a starting place, as the companies may not have all of the information they need to make fully informed estimates.)
  
• Some solar manufacturers, including Tesla and REC, have their own certified networks of installers. You can get a quote and get connected to local installers directly through their websites.

What to look for when you reach out for quotes:

If you are calling installers directly, here are some tips for what you should ask for or look for in a quote. (If you are using an online resource like EnergySage that finds quotes for you, use the following to help you ask follow-up questions or refine the proposals.)

1. Vet the company

A few questions you should ask:

• How long have you been in business? Solar is a tough business, and many companies go under within a few years. You want to make sure your installer has proven longevity so that they can help you in the future if any issues arise.
  
• Are your employees certified with the North American Board of Certified Energy Practitioners? NABCEP is an accreditation organization for renewable energy professionals. It costs money for individuals and companies to get certified, and it shouldn’t necessarily be a dealbreaker if your installer is not certified. However, those certified by NABCEP must meet minimum professional experience and training requirements, so it’s a helpful data point.

2. Know what size system you want

One of the first questions an installer might ask you is how big you want the system to be. You may want to see quotes for multiple options in order to compare them. Options include:

• Matching the system to your average annual energy use
  
• Oversizing the system to generate more power than you typically use in a year
• Undersizing the system to generate less power than you use in a year

3. Understand your financing options

Most installers will include a financing option in their quote. Horowitz noted that some installers advertise very low interest rates that are below market rate. They are typically able to do this by paying a “dealer fee” to the bank, which they incorporate into the price of your installation — in other words, if your interest rate seems too good to be true, the total cost of your installation will likely be higher than it otherwise would be. To get a better sense of the true cost, ask for quotes both with and without financing options.

4. Consider a battery

Adding energy storage, a.k.a. a battery, to your solar array can add another 10 grand or more to the project cost. But there are a few reasons it might be worth it:

• You want backup power during a blackout.
  As I mentioned earlier, solar panels alone won’t power your house when the grid is down. But if you have a battery, you can store the energy they generate and use it to power essential systems like your refrigerator and air conditioner during an outage. Note that you will not save additional money with a battery, unless…

• Your utility offers time-of-use rates
  If what you pay for electricity varies throughout the day or your utility offers an option to switch to this kind of pricing scheme, then a battery will enable you to arbitrage prices by tapping into your stash of electrons when prices hit their peak. Ask your contractor if they can help set the battery to maximize your bill savings. Aligning with time-of-use pricing doesn’t necessarily maximize your carbon savings, however. For that, look into…

• Grid services or virtual power plant programs
  In some jurisdictions, you can sign up to give your utility or a third party the ability to take control of your battery and charge it or discharge it strategically to help the electric grid. For example, when demand is expected to peak on a hot summer day, these programs might discharge thousands of residential batteries in order to prevent the utility from having to deploy dirty (and expensive) “peaker” plants, which are usually powered by natural gas or oil. These programs offer either up-front rebates for batteries or will pay you for your participation, or both. The key thing is you have to buy a battery that’s compatible with the program.

In conclusion, if you just want back-up power, any battery that’s large enough to power your essential systems should do. If you want to pay off the investment, look into time-of-use rates. If you want your investment to go further for decarbonization, ask your contractor if there are local grid services programs available, and if any of their products are compatible.

YOU HAVE THREE QUOTES. NOW WHAT?

After you get a few quotes, you’re going to want to spend some time comparing them, asking questions, and potentially soliciting additional quotes with variations on the system. If you’re feeling overwhelmed or you don’t have the time or patience to sort through the details on your own, you can also call the Solar United Neighbors Help Desk, which offers a free quote review service.

1. Compare the price per watt

The most important number on the quote is the price per watt, not the total system cost. That is the number you should be comparing between different installers, as the quotes may be for differently sized systems.

You should also compare the annual bill savings. If two different companies quote you significantly different savings for systems that are roughly the same size, one of them has likely done a more detailed analysis of your roof than the other.

“It doesn't matter what module you have, from which manufacturer, or what inverter you have. There really is no difference in what your system can produce if it's the same size,” said Bowie.

Lastly, if the quote is for a solar lease, or includes a financing option, look at the monthly payments.

2. Compare the equipment

Every installer has certain brands and types of equipment they work with. Our expert panel agreed that it’s important to look at the brand names the installer is offering for the solar panels, inverters, and batteries, and to make sure they are from reputable companies that have been around for at least five years — even if it means paying more. A quick internet search of the top 10 residential solar panel brands should give you a taste of what those companies are.

“It is definitely worth paying a little bit extra to have really good equipment,” Vernetti said.

You may also see installers advertise that they offer “Tier 1” solar panels. That means the manufacturer has been designated “bankable” by Bloomberg New Energy Finance. The designation is more related to finance than product quality, but many solar companies use it as a rough proxy for reliability.

That being said, don’t get too bogged down in comparing solar brands.

“There's not a huge difference, typically, between one solar panel and the next of the Tier 1 manufacturers,” said Bowie. “A lot of solar companies will maybe offer one or two different manufacturers, and then maybe beyond that one or two different sizes.”

When it comes to inverters, you do want to pay attention to whether your quote includes string inverters, microinverters, or power optimizers. In a system with a string inverter, your panels will all be wired to one central inverter. This is generally the cheapest option, but it is less durable and may need to be replaced, said Vernetti, whose employer, Enphase, is the leading producer of microinverters. String inverters can also limit the output of your system if part of the roof gets more shade.

The other two options are more expensive but get around the issue with shade. A system with power optimizers is similar to one with a string inverter, but each panel will also have a small device attached to it that regulates the output and maximizes your system’s performance. By contrast, microinverters are small inverters attached to each individual panel. Both of these options also allow you to monitor each panel’s performance.

Bowie said the two were comparable in terms of performance and price. A key consideration, he said, is that your choice of inverter can begin to lock you into using the same brand of equipment on other home upgrades you might do down the line. “If you're an EnPhase customer, you're likely going to be going down the track of an EnPhase battery storage system,” he said. “Whether the customers know it or not, they're kind of being pushed down a path towards this manufacturer for more things in their home, like batteries, whole home controls, electric vehicle charging."

3. Pay close attention to the warranties

Your quote should provide information about warranties offered by the manufacturers of the panels, inverters, and batteries, as well as by the installation company. 25-year warranties are standard, but the details vary by installation company and by manufacturer. For example, your inverters may have a 25-year warranty, meaning you can get replacement inverters for free if any of them fails within that time period — but if you don’t have a warranty on labor, it could cost you several hundred dollars to get them installed.

“It's really important for customers to read the fine print and to talk with their local solar company who is quoting the system for them to uncover what the warranties mean,” said Bowie.

This is especially important if you are installing batteries. Ask your installer about both the equipment warranty and their policy is for servicing the equipment.

4. Look into other financing options

Most solar installers offer financing options. Your quote should include the name of the lender the installer works with, the down payment, monthly payment, financing term, and interest rate. However, you may find a better deal elsewhere. Horowitz noted that installers like using their own financing companies because it speeds up the sales process — they can approve you for a loan just by putting in your social security number, and sell it to you at the same time as the contract. But you may find a better deal elsewhere.

“Talk to your bank, talk to your credit union, look at home equity lines of credit, see what other options you have out there, and if those have lower interest rates or better payment terms,” said Horowitz. “You are not required to use their finance.”

WHAT’S NEXT?

After you’ve found an installer, settled on a system design, and secured financing, all that’s left to do is sign your contract. Then, you wait. Your installer will have to obtain permits from your city, county, or state, as well as an interconnection agreement with your utility.

One way to try to minimize the wait time is by working with an installer with lots of local experience. They’ll be better equipped to navigate the permitting process. For example, if you want Tesla solar panels but Tesla hasn’t done many installations in your community, it may take longer for the company to get through this stage.

After these two steps are complete, the solar company will reach out to you to schedule the installation, which should only take a few days.

After the system is installed, you may have to wait for a final inspection from your utility or a verified third party for permission to operate the system.

CONGRATULATIONS, YOU’VE GOT SOLAR PANELS!

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