Installing solar panels on your roof can both save you energy costs and reduce your home’s environmental impact. Even though there are some DIY solar panel options, installing them is a highly complex project, and you’ll still need assistance from an experienced professional. Join This Old House energy expert Ross Trethewey and solar power installer Anukene Warda for a look into the installation process.
Planning Your Solar Panel Installation
Before you begin the installation process, properly plan your solar panel system. This involves assessing your roof’s suitability, determining the number of panels you need, and obtaining the necessary permits.
Assessing Your Roof
The first step in planning your solar panel installation is to evaluate your roof’s condition and suitability. In the Northern Hemisphere, a south-facing roof pitched between 30 and 45 degrees is considered ideal for solar panels.
Your roof should be in good condition and able to support the additional weight. You should also identify obstructions, such as nearby trees or buildings, that could cast shadows on your panels.
Determining Panel Quantity and Layout
Once you’ve assessed your roof, you must calculate how many solar panels you need and determine how to arrange them. A solar contractor will recommend the best layouts based on your energy consumption, available space, and budget constraints.
Obtaining Permits and Approvals
Before installation, your contractor must secure the necessary permits and approvals. You may need building permits from your city government, electrical permits, and approval from an HOA if you’re part of one. You’ll also need to get your utility company’s signoff to connect the solar panels to the power grid, which may let you sell the energy you don’t use in exchange for incentives.
Be sure you have all required documentation before you proceed to ensure everyone’s on the same page and avoid costly penalties.
Installing Roof Attachments
The first step in the physical installation process is securing the roof attachments supporting the solar panels.
First, the installer will find the rafters beneath your roof shingles. They’ll either use a stud finder or measure from the roof’s edge to find the rafters, typically spaced 16–24 inches apart.
Then, it’s time to install the stanchions for a strong hold on the panels. “Essentially,” says Warda, “what they are is a lag bolt that goes straight into your roof rafters for a good, strong connection, a big flashing that keeps everything watertight, and a stanchion that goes about 6 inches off the roof.” Your solar contractor should use roofing sealant around the holes in addition to flashing for the best seal possible.
Installing Solar Mounting Rails
With the stanchions in place, the next step is installing the racking to support the solar panels.
Trethewey and Warda use aluminum rails for their project, securing them to the stanchions with stainless steel bolts. The bolts should be tight enough to stay secure in tough weather conditions.
Each mounting rail must be square to properly align the solar panels. Trethewey and Warda each measure diagonally from the end of the topmost rail to the end of the bottommost rail. Once everything is checked, they install the other rails the same way.
Wiring and Electrical Work for Solar Panels
Before the panels can go on, their electrical conduit and wiring must be in place. A licensed electrician is often the one doing this work.
First, Warda runs conduit from the roof to the home’s main electrical panel according to local codes. The necessary wiring will run through them to connect the panels to the electrical system.
Since solar panels generate DC power, you’ll need to use an inverter to convert the energy to AC power for your home. Some systems use a central inverter, but these have a major drawback: if one panel malfunctions, the rest of the array can also go down.
Trethewey and Warda use microinverters under each panel to preserve the system’s efficiency. Finally, they use six-gauge copper wire to ground the entire system, including the rails.
Mounting Solar Panels
With the mounting system and electrical components in place, Trethewey and Warda install the solar panels. Each panel is bulky and heavy, so lifting them onto the roof is often a two-person job.
Once each panel is in place, Trethewey and Warda connect it to the microinverter and fasten everything to the rails with clips and clamps. Manufacturers commonly specify the torque necessary to hold everything in place.
Completing Electrical Connections for Solar Panels
The final step in the installation process is completing the electrical connections to integrate your solar system with your home’s electrical setup. An electrician will run wires from the roof through a new meter that measures solar production and then connect the wires to a new electrical subpanel. Finally, they’ll terminate the neutral wire and connect the two hot legs to a standard breaker.
Once Warda makes his final checks, he turns on the system and confirms the meter shows power being produced.
Solar Panel Monitoring and Maintenance
After installation, you’ll need to clean the panels regularly. Dust, debris, and dirt can stop them from working at their best. Different manufacturers recommend different methods, but a gentle rinse with water and a soft brush often suffices. Solar contractors can often do the job for you as part of a maintenance plan.
Watch the system for any signs of wear or damage, such as loose bolts, frayed wires, or cracked panels. Addressing these problems early can stop them from snowballing into larger issues.
