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What's the Solar Panel Installation Timeline from Purchase to Power?

Going solar is a process that can take anywhere from two to six months or even longer.

Two people installing a solar panel on a terra cotta style roof.
The actual installation of solar panels on your roof is one of the quickest parts of the purchasing process.
Mischa Keijser/Getty Images

In the next 10 years, three times as much solar power will be installed in the US as in all the years before 2021. Given that rooftop solar installations have reached record numbers each of the last few years, this rapid expansion should come as no surprise.

While many people are going solar, it can be a lengthy process. Before signing a contract, you'll need to make sure your home is a good fit, find a good solar company and collect and compare a few quotes. After that, others will take care of permitting, installing and giving final approval to your solar panels.

While waiting may seem like just an inconvenience, how quickly your solar panels get up and running can actually impact your overall savings. The federal solar tax credit reduces at the end of the year and net metering plans are being reconsidered around the county. When you're up against one of these deadlines, understanding how long the entire installation process takes can inform your decision making. Here's what you need to know.

The SaveOnEnergy marketplace helps you search, compare, sign up and save on the right energy fit for your home — all for free. If you're interested in solar, answer a few questions to get an exact price quote from our solar advisors.

Supply chain issues and personal research

There are a couple of points in the process of buying solar that are hard to schedule out.

One variable is that the current supply chain issues haven't skipped the solar industry and means 2022 is a more uncertain year than normal for solar. So far, residential solar installations have continued to set records, while most of the delays have affected industrial and utility-scale installations.

Read moreShould You Invest in Solar Panels in 2022? It's Complicated

Another variable is the time you spend doing your own research and soliciting quotes. Because the residential solar industry is highly competitive, salespeople are highly responsive. This step will take as long as you need. Pressure to sign a contract quickly could be a sign of a scammy company, so beware.

Solar companies may have slightly different processes, so your experience might vary from the one outlined below. Even so, it'll give you a good idea of how the process generally works and how long it'll take.

Solar site assessment and system design

Before a solar company can install the panels, they need to design a system that fits your roof. This almost always involves a solar professional visiting your home for an assessment. They should ensure that your roof won't need replacing before installation and that it isn't too shaded by trees or other buildings. If your house needs a new roof or trees need to be trimmed, your timeline is going to get a bit longer.

After assessing your home, your solar contractor will design your system to fit your roof and your energy needs. You'll accept the final design and sign a contract. Different experts estimate this stage takes anywhere from one to four weeks.

Permits and approval

After you sign off on your solar system design, your city or local authority needs to as well. From the time your solar installer submits the necessary permits to the time of installation depends on the permitting process, which some local governments have chosen to speed up.

Estimates range from three to 11 weeks. You can get an idea of how quickly permitting takes with the clickable map in the Solar TRACE tool from the National Renewable Energy Laboratory, though only for areas with enough data to provide estimates.

Solar panels being installed on a roof.

It can take a few months to go from signing a contract to generating solar power.

Eloi_Omella/Getty Images


Perhaps the most exciting part of the solar installation process is also one of the quickest. Installation -- when workers are on your roof attaching panels -- takes only a few days, even for complicated jobs. Expect it to be done in three days or fewer.

Permission to operate

After installation, you can't just flip a switch and start using electricity from your panels. Your city needs to inspect the installation and make sure it's up to code. The Solar TRACE tool can give you an idea of how long this will take in a few places, though a couple of weeks is a fair estimate.

The final step is getting approval of the system from your utility, called permission to operate, or PTO. Because the utility has an obligation to provide the electricity needed within their territory, they need to approve projects that send energy to the grid.

Depending on the utility, this can vary dramatically, but some estimates say it will take three to eight weeks after installation to get permission to operate.

In total, from system design to permission to operate, your solar purchasing process could be anywhere from two to six months, though some set the cap at four months.

The timeline is something you'll want to discuss with your installer before signing a contract. While unexpected delays pop up, having a general idea of how long each step takes will help you identify irregular or unreasonable delays throughout the process. The quicker you get those final permissions, the quicker you can start saving money.

If you're considering switching to solar energy or simply looking to learn more about solar, here's some additional resources: