Think of your solar array as a 25-year investment. Solar panels will produce electricity for at least 25 years. Your panels will continue to generate electricity after 25 years but at a decreasing rate. While micro-inverters will likely last the duration of the PV system, you may need to replace the central inverters after 15 years.

The size of your optimal solar array will be influenced by many variables. Before analyzing those variables, you should understand how solar is sized and measured. The electrical capacity of solar panels is measured in watts (W). The typical solar panel is rated at 250-300 W. Your installer will estimate how many panels can fit on your roof given its footprint and shade susceptibility to determine the ideal size of your system.

Unlike other energy technologies, solar PV contains no moving parts.

This means it’s not likely your equipment will fail. You should not have to replace your panels at all during their lifetime. Depending on your inverter type, you may also need to have your inverter replaced 10 to 12 years after installation. Extended warranties can cover this equipment replacement cost. Ask your installer for details.

Energy payback is the amount of time it takes a solar panel to produce more energy than was used to produce it. This time varies by panel and by technology. Even as far back as 2004 when manufacturing processes were less efficient, it took less than four years for a standard solar panel to generate more energy than was used in making it. And remember, solar panels can generate electricity for 25 years or longer!

Most solar arrays don’t have batteries. Most residential solar arrays in the United States remain grid-tied, meaning they’re connected to the utility electric grid. Grid-tied solar arrays are significantly less expensive than arrays with batteries. Standalone solar arrays are also more efficient than solar paired with storage.

There are four factors that determine if your roof is a good fit for solar:

Ideally, you should have a south-facing roof. In the northern hemisphere, south-facing roofs maximize the amount of sunlight your solar panels collect. The more sunlight they collect, the more electricity they produce, and the quicker you can pay off your system. You can still mount solar panels to your roof if it faces due east or west, but the panels will produce less energy (about 75% of what a south-facing roof would produce). If you have a flat roof, the panels can be engineered to face due south no matter how your roof is oriented.

Because solar permitting is handled by the local municipality, the permitting process will vary based on where you live. Most localities require installers to file for a solar permit, the stipulations of which differ by jurisdiction. Solar permits are in place to ensure that your system is installed safely and follows local code.

The Solar Investment Tax Credit (ITC) is a federal tax credit that allows homeowners to deduct a portion of their solar costs from their owed taxes. As a homeowner, you can take advantage of this tax credit when you file your taxes, potentially leading to reduced or even zero tax obligations. The value of the ITC has recently been elevated from 26% to 30%, making the switch to solar even more enticing. 

See guide here for more information.