Solar Panels

How Long Does it Take to Install Solar Panels?

By:Michael Johns

installing solar panels

When you first decide to install solar panels on your house it’s super exciting.

There’s so many life changing benefits including huge savings on your electricity bills for years to come. 

Like any large investment, you don’t and can’t just rush into it. You won’t just be able to click order online and the system magically appears the next day. There’s a strict procedure to follow when buying a solar panel system. Without the correct due diligence, you could be left with an ineffective and unpermitted installation.

So how long does it take to install solar panels? Well, it usually takes a minimum of three months from the moment you find a company to carry out the work.

In this article, you’ll find out more about the time it takes to install solar panels, the steps you need to take, and mistakes to avoid. 

Solar Panel Installation Process and Timeframe

It will take at least 3 months for a successful solar panel installation but it can take longer. The frame is not an exact number as there are several external factors to deal with including design and permits. Let’s take a look at the step-by-step process and how long each part takes to complete.

Initial Assessment

Once you find and agree on a solar panel installer you can get the ball rolling. The company will need to do a survey of your property and roof. This is to make sure it is suitable for solar, measure the roof dimensions, and ensure the roof is in good condition.

The installer will also take a light reading and identify the most suitable areas for solar panels. Don’t expect your whole roof to be covered with panels, the orientation, pitch, and shading are all key to the most optimal system.

The timespan for an assessment can vary from company to company and how busy they are. Generally, you will find they are quick to respond to this work to ensure the contract is secured and work can begin. Usually, you can expect an initial assessment to be completed within a week of agreement.

Solar Array Design

With the measurements, the design team can then put together plans for your bespoke system. The data obtained during the assessment enables the plans for the system to be drawn up including the size and number of panels, installation location, and estimated electricity production.

solar panel design plans
Solar array design example

In addition, the design engineer will ensure the plans conform to local regulations. You will need a permit from your local town or city in order to carry out the installation. A reputable installer will have complete knowledge of the regulations in order to tailor your system to permit requirements.

Once the design and plans are completed you will then receive a more accurate quote for the equipment and installation. 

This design process generally takes 2 to 4 weeks.

Obtaining Permits

Once the plans are approved they can be sent off to the local Building and Safety Department. This is a crucial step which you must adhere to. Without a permit, you won’t be able to gain permission to switch on your system and connect to the main grid. In addition, it can be costly to go back and make alterations or remove the system if you fall foul.

As you are reliant on local government, this can take a while and it varies from town to town. Getting the plans and paperwork correct when you first apply will help speed up the process.

It can take a month or more to have the permit approved!

Installation Time

With the permit approved you can now move on to the physical installation. After 2 months or more of planning and paperwork, you’ll be delighted to see the solar array finally arrive!

The good news is that mounting and wiring up the system is a quick process and can be done in 1 to 3 days depending on the size and complexity. Quite often, it is even completed in a single day.

Solar panels being installed on roof

To complete the job solar panels will be mounted to your roof, drilling is usually required for the racking. Plus wiring and a solar inverter is installed to run the system. You should ensure the installer talks you through how everything works and that the energy monitoring system is set up. This will help you to make sure everything is working correctly in the future.

Unfortunately, you won’t be able to switch on the system immediately as there needs to be final check and permissions.

Final Inspection

Now everything is in place, the city building inspectors will need to take a look in order to ensure everything is up to code. This is required to check the system is safe and conforms to the original plans. Expect the inspector to investigate the structural integrity of your roof and electrical wiring for everyone’s safety.

Once again you’ll have to wait for the local city to spring into action here. This could take weeks or over a month.


With the go-ahead from the building inspector you are nearly ready to activate the system. Your installer will then need to get Permission to Operate (PTO) from your utility supplier. At some point, the energy company will need to set up your Net Energy Metering so you can record electricity flowing to and from the main grid. This is done with a bi-directional meter which enables you to sell excess energy back to your utility provider.

This can take 1 or 2 weeks for your utility company to add the NEM meter.

Once you are granted PTO, you can go ahead and switch on your system. Your installer should have shown you how to do this or show up to do it on your behalf.

It only takes a few minutes to request and receive PTO if everything is present and correct.

What Can Slow Things Down?

As you can see there’s at least 6 hoops to jump through between your first agreement and activating your solar array. Of course, everything is not always straightforward and there’s a number of problems that can slow the process up even more.

Roof Repairs

Solar panels are built to last at least 25 years. So you need a roof that can support the extra weight for a long time. To be honest, it goes without saying that your roof should be in a good state of repair. Any homeowner should ensure their roof is strong and watertight. 

Often the assessor will spot issues with your roof that requires attention. These repairs will need to be completed by a roofing company before any solar work can continue. Remember, your property will need to pass local building codes.

Red Tape and Paperwork

The wheels of local government can turn very slowly, particularly if there are errors in your paperwork. Along with getting high-quality equipment and workmanship, a reputable solar installer should be confident in handling all the design and paperwork. Their engineers should design your system with knowledge of local regulations and understand how to submit the permit applications. 

Sometimes you might be waiting for the paperwork to be processed but it’s going to take a lot longer if it’s rejected and needs to be resubmitted! Errors like this can cost you months.

Equipment Supply Issues

Solar panels are built using silicon semiconductors which are used in virtually all electronics these days. The supply chain of this material has come under pressure since 2020 which leaves people waiting a long time for stock. This includes solar panel companies which can struggle to keep up with supply and demand. It’s always worth checking if your installer has plenty of stock and suppliers before making your choice. 

Type of Roof

The actual installation of the solar array is probably the quickest part of the whole process. This should take a day or two, but it’s true that the type of roof can slow things down a little. For example, it is much easier to mount solar panels on a standing seam metal roof compared to slate tiles. Adding to this, the pitch can add complexity with workmen struggling on steep angles or adding tilt mounts on flat rooftops. There’s little you can do about this except choosing an installer who has experience in working on similar jobs.

What if the Installation is Done Wrong?

Not all solar systems are equal and the increase in demand has led to a rise in cowboy installers. A reputable company should always provide a workmanship, parts, and power output warranty. That way you are covered by any problems.

Poor Design

A poorly designed system will likely lack performance. This can be due to any number of factors from incorrect orientation and placement. A poorly designed system may include:

No Permits

Never try to go ahead with the installation before you receive permission for the local Building and Safety Department. This will cost you further down the line. You won’t be able to activate your array until you have it approved by the city and utility provider. Without correct plans and permits, you can be forced to make changes or remove them completely. This costs time and money. Don’t cut corners.

How Long to Install Solar Panels Summary

There’s no getting around the fact that you’ll have to wait at least 3 months before your solar panels get to work. 

For a successful installation, everything needs to be carefully calculated, planned, and approved. This can feel like a long time but remember it’s a large investment that is going to pay off for over two decades.