What You Need to Know About Installing Solar Panels on Your Roof

Wouldn’t it be great if the rising sun could help lower your energy bills?

For many green-minded Americans, solar-powered homes are becoming more and more attractive as an alternate home energy source each year. According to a survey conducted by Stanford University in 2018, there are over 1.47 million solar roofs in the contiguous United States alone, and that number is growing quickly each year.

However, unlike installing high-efficiency appliances or other eco-friendly home measures, solar panels can be a costly investment upfront. Plus, because they are fastened structurally to your home’s roof, rooftop solar panels require a little more planning than, say, purchasing a new dishwasher might.

Wondering if you’re ready to go solar? We’ve got eight important things to think about if you’re considering installing solar panels on your roof, plus professional tips from the experts at Solar Stack.

8 things to consider when installing solar panels

 1. Your home’s location

When it comes to installing solar panels, location is incredibly important - and it’s not for the reason you might be thinking.

Most people believe that solar panels are only ideal in sunny states like California or Texas when most states actually have good-to-excellent sun capacity, according to the U.S. Department of Energy.

What’s more, even cloudy areas (like Alaska and the Pacific Northwest) can see cost benefits to installing solar panel systems at home. In fact, these areas have solar resource levels similar to Germany, a country with a much more developed solar infrastructure than the United States.

So why is location so important? Two words: tax incentives.

Currently, a federal tax credit of 26% is available to any citizen who installs a solar panel system until December 2022.

However, every single state currently offers some sort of renewable energy or energy efficiency incentive to home and business owners looking to improve their carbon footprint. In many states, this includes the installation of residential solar panels.

California offers the most incentives at 146, while West Virginia offers the fewest at 10. However, you might be surprised at the top 10 states offering renewable energy tax incentive.

Top 10 states offering the most energy tax incentives

See the full list at the Database of State Incentives for Renewables and Efficiency.

2. The direction of your roof

To produce the maximum amount of energy possible using your solar panels, solar panel placement is extremely important.

In the United States, solar panels should generally face the south, because in the northern hemisphere, the sun always travels along the southern part of the sky. Because of this, you’ll want to make sure that the southern portion of your roof is large enough to accommodate the number of panels you want to install.

Additionally, the best angle for your solar panels depends on your home’s latitude. While you can adjust your solar panels’ placement to get the most energy production out of them throughout different seasons, the easier, set-it-and-forget-it method is to set them at an angle equal to your latitude.

For example, if you live in Dallas, Texas with a latitude of 32.77, you could leave your solar panels tilted at 33 degrees for optimal, year-round solar energy production.

3. Shade obstacles to your roof

Anything taller that blocks sunlight from your roof - even for only a few hours a day - could be a potential obstacle to your roof solar panels’ effectiveness. Before calling a solar installer, make sure that the south-facing portion of your roof is not shaded by:

• Other homes or buildings.
• Tall trees.
• Mountains or other natural formations.

4. Your roof’s condition and its materials

The average residential solar panel weighs about 40 pounds and is around 5.4 feet by 3.25 feet in size- not exactly a small addition to your roof, especially when adding five or ten panels at a time.

Because of this, it’s important to make sure that your roof is the right condition, size and condition to hold up these panels for the long run.

Important factors about your roof to consider

• Age: Generally, you should only install solar panels on newer roofs, or roofs that are in excellent condition. If your roof is five years old or older, consider hiring a roofing contractor or inspector to ensure it is solar-panel ready.
• Size: The right-size roof for solar panels depends on your goals for energy output. Are you looking to save money? Reduce your carbon footprint by a little or a lot? How much energy do you consume currently? The average U.S. solar installation takes about 20 panels, but a solar contractor can help you determine how many panels you need and whether or not your roof can accommodate.
• Material: Finally, your roof’s material plays a big role in the mounting options you can choose. For instance, for asphalt roofs, you may want to use an invasive mounting method like a railed system, while for a concrete or tile roof, you may want to choose a mounting method that doesn’t involve creating holes in your roof.

5. Solar panel mount options

Before simply sticking solar panels on your roof, it’s important to think about how you will be sticking them up there. There are several solar panel mounting options available, all of which fall into two broad categories: invasive and non-invasive.

Invasive mounting systems require holes to be drilled into your roof in order to securely attach the panels to the roof’s trusses, while non-invasive methods use other tactics to either weight down or adhere the panels to the surface of the roof.

Invasive solar mounting options

Rail mounts

This method requires the installation of a rail system that serves as the base of the solar panels. The rails themselves are bolted to the trusses of the roof, with flashing installed around each bolt to protect from leaks and water damage below. Each solar panel is then connected to two parallel rails using clamps.

Railless mounts

As their name implies, railless mounts have no rail system and solar panels are installed directly into the roof using hardware. Using railless mounts typically cost less and require less installation time than rail mounts, as they have fewer components.

Shared-rail mounts

A shared-rail mount serves as a nice middle ground between railless and rail mounts. Rather than eliminating all rails, this system allows solar panels to share central rails, providing a solid foundation while also requiring less materials for the installation.

Non-invasive solar mounting options

While invasive solar panel mounts may seem like the more durable option, they can potentially open your home up to water damage if done incorrectly. Sam Mitchum, Operations Manager at Solar Stack, explains:

If you’re not interested in an invasive roof mount, don’t worry - there are several popular non-invasive mounting options you can explore as well.

Ballasted mounts

Ballasted mounts involve using large concrete blocks to weight down your solar panels on either side of the roof. While these mounting systems are not approved for use in high-wind or hurricane-prone climates like that of South Florida, they can be a cost-effective, non-invasive way to anchor your photovoltaic system to the roof in mild, temperate areas.

Foam adhesive mounts

Finally, Solar Stack’s foam adhesive mounts are gaining in popularity due to their durability and non-destructive installation technique. This method uses extremely strong spray polyurethane foam or SPF to attach metal pedestals to your roof. Your solar panels are then installed on the aluminum pedestals. While not yet approved for shingle or silicone-coated roofs, foam adhesive mounts are approved for just about every other roof type, both residential and commercial, and can be used in a wide range of climates.

6. Solar panel options

There are three main options when it comes to solar panels: monocrystalline, polycrystalline and thin-film. There are several technical differences between each panel, but the best solar panels to install on your roof will depend on your budget and your energy-saving goals. Generally, monocrystalline panels are the most efficient and most expensive panels, while thin-film are the least efficient and least expensive.

Data from SolarReviews.com.

7. The cost of your solar options

While the cost of the panels themselves is a good thing to keep in mind, remember that this does not reflect the cost of installing the entire solar panel system.

According to the Center for Sustainable Energy, the average cost for a residential photovoltaic system is between $3 - $5 per watt. This amounts to anywhere between $15,000 - $25,000 in installation costs.

Points 1 - 6 are important to consider when determining your system’s estimated return on investment, and a qualified solar company can help you find out just how long it will take for your system to break even.

8. The expertise of your installers

Once you’ve taken some time to investigate your roof’s health, research panel types, think about mounting options and prepare for installation costs, it’s time to start looking for a good contractor. But what should you look for in a solar panel installer?

One thing to ask about is the company’s experience in general roofing repair and/or installation. While many companies have popped up to meet the growing demand for solar, not all of them are well-versed in roofing techniques.

A poor solar panel installation can do serious damage to your roof and the home it protects, so it’s good to go with a contractor who is very familiar with your roof type, as well as local structural codes and requirements.

Additionally, if you’re using a ballasted mounting system to reduce roof penetrations, you’ll want to make sure the company has a solid understanding of what’s needed to anchor your panels to the roof. Ask your solar installer if they have a licensed structural professional engineer (PE) on staff, or if they have the name a third-party PE to assist with your project.