CUB's Guide to Rooftop Solar

Now more than ever, installing solar at home can be a good financial investment
for homeowners, thanks to the rapidly declining cost of solar panels and new state incentives through Illinois’ Future Energy Jobs Act, groundbreaking legislation passed in 2016.

I'm interested in installing solar in my home, where do I start?

The ideal residential solar installation finds a balance between your energy needs, your roof’s generation potential, and the costs of the system. Ask these questions to help determine if your home is suitable for solar panels.
(Note: An on-site evaluation will give you a more accurate estimation of your home’s potential for solar. The checklist below is only meant to help you get started.)

How much of your roof is shaded?
Check out an aerial view of your home on Google Maps. If you can’t see the majority of your roof, you may not get enough sunlight to justify the costs of installing your own system.

How old is your roof?
Replacing your roof after installing a solar panel system creates additional costs, so most developers recommend installing a system on a relatively new roof.

Can the size, shape and slope of your roof support solar panels?
South-facing roofs that sit at an angle of 15 to 40 degrees tend to be the best, although east and west-facing roofs can often work too.

What type of material is your roof?
Asphalt, tile and metal roofs tend to be an easier surface for installing solar panels. Slate and wood roofs are more difficult to install solar panels on and make for more expensive installations.

Can I install panels somewhere other than my roof?
Not all residential solar systems are installed on a roof. If you have open land that gets a lot of sun, a ground mount system could be a good alternative to installing a system on your house.

Did you know…
The price of solar panels has declined 70% since 2010.
Source: Solar Energy Industries Association

How much energy can your roof generate?

Solar installers will help you determine how much electricity a system will generate over time, but if you’re interested in roughly estimating your home’s generation potential, check the National Renewable Energy Laboratory’s calculator: http://pvwatt

How much energy do you use?

If you’re considering installing solar panels, look at your home’s typical energy usage. How much do you use each month and annually? Are there energy efficiency upgrades you can make before installing solar? Minimizing your home’s energy usage before installing solar panels can keep you from paying for more panels than necessary.

What is net metering?

In Illinois, solar system owners can connect their panels to their utility’s grid and receive credits on their electric bills for any excess solar energy their home doesn’t use. This policy, often referred to as “Net Metering,” is free and helps solar owners maximize the economic return of their panels.

Instead of sending the excess electricity back to the grid, you could use a battery to store the power. However, because of “net metering,” integrating battery storage is typically not worth the additional cost. (Note: CUB looks to the cost of battery storage coming down enough to make this an option.) If you choose to keep your system entirely “off-grid”—meaning it’s not connected to the power grid—you also wouldn’t be eligible for state solar incentives.

How do I find solar installers?

If you think rooftop solar would be a good fit for you, contact solar installers in
your area to get quotes for your project. Comparing as many solar options as possible can help you avoid paying inflated prices for your system. CUB recommends talking to at least three installers before signing any contracts. Find residential solar installers near you by visiting the Illinois Solar Energy Association website:

What solar incentives are available?

The average 5 kilowatt (kW) system in Illinois costs about $15,600. A 5 kW system can produce anywhere from 450 kilowatt-hours (kWh) to 800 kWh of electricity a month, depending on sun exposure, roof tilt, weather and many other factors. In Illinois, there are three separate incentives that help off set the costs for consumers who install residential solar:

1. The Federal Solar Investment Tax Credit: This tax credit allows you to deduct 30 percent of your solar project costs from your federal taxes. The credit is available through 2019, but it drops to 26 percent in 2020
and 21 percent in 2021. This incentive does not depend on how much energy your system produces, but you must pay federal taxes in order to benefit. If 30 percent of your project costs amounts to more than you paid in federal taxes in a single year, you’ll receive the rest of your incentive the following year. (For example, if 30 percent of your project costs is $5,000 but you only paid $3,000 in taxes, you’ll receive $3,000 in the first year and then $2,000 the following year).

2. Solar Renewable Energy Credits: Thanks to the Future Energy Jobs Act, the state will purchase the “Solar Renewable Energy Credits,” or SRECs, that your system produces at a set dollar amount. For residential solar, this incentive is an upfront payment determined by how much energy your system is expected to produce over 15 years. Since the amount of energy generated by solar installations varies widely, the percentage of the project costs that this incentive will cover also varies. Your solar installer will help you determine how much of your project you can expect this incentive to cover.

3. On-bill Credits from your Electric Utility: Once you have installed your system it’s likely you will not always be using 100 percent of the electricity it produces in real time. If your system is connected to your utility’s grid, excess electricity is sent back to the grid and you’ll receive bill credits for that electricity in a process called “net metering.” These credits help maximize your monthly bill savings and ensure you’re credited for every kWh your system produces, which helps pay off the remaining installation costs faster. They also help cover the cost of the electricity your household uses when your panels are not generating energy (i.e. cloudy days or nighttime). Note that the credits expire after 12 months and do not “cash out,” so it is wise to make sure your system does not produce more electricity than your expected annual usage.

Note: All residential customers of the regulated electric utilities ComEd, Ameren, and MidAmerican can participate in “net metering.” If you have a municipal electric utility or cooperative, check to see if it offers their customers “net metering.”

Can residential solar panel owners participate in a "real-time" pricing program?

ComEd and Ameren customers with rooftop solar installations can still participate in their utility’s realtime pricing program (“Hourly Pricing” for ComEd, “Power Smart Pricing” for Ameren). In fact, solar customers often benefit from real-time pricing, which charges participants a market rate that can change hourly. That’s because they can pull electricity from their panels during hot summer afternoons and avoid paying peak prices for electricity. (Note: If you have an electric vehicle, adding real-time pricing makes even more sense. Charge your vehicle at night, when prices are typically lower, and your net metering credits will cover more of your car-charging expenses.)

Can residential solar panel owners have an alternative electric supplier?

Yes. Solar panel owners with an alternative electric supplier still qualify for the federal and state incentive programs. Additionally, suppliers are required by law to provide net-metering, and customers will receive credits at the rate at which they pay their supplier. (Note: You are likely to lose money with an alternative supplier, compared with rates from the regulated utility. In recent years, Illinois consumers have lost hundreds of millions of dollars on alternative electric suppliers. Be careful!)

Did you know…
Homeowners who get
3 or more quotes save
10% or more.
Source: U.S. Dept.
of Energy’s National
Renewable Energy
Laboratory (NREL)

What are my options for financing my solar system?

There are many different ways to finance a solar installation on your home. CUB recommends going with whatever option is best for you.

Purchasing vs. Leasing.
Some solar installers off er the option of leasing solar panels instead of purchasing them outright. When you lease solar panels, you typically pay a monthly fee to the installer and do not own the panels or receive any of the federal or state incentives directly. Rather, the installer owns the system, receives the incentives, and ideally passes the savings onto you. While usually requiring no upfront cost, solar panel leasing agreements are still a long-term commitment.

How to pay for your system if you want to own it:
If you decide to own your solar panel system, there are a few ways to pay for the installation costs. Generally, there are two types of loans that can help pay for your system.

1. Bridge loan: A bridge loan covers the period between installing your system and receiving your federal and state incentives.

2. Solar loan: After subtracting your federal and state incentives from your total installation costs, you can finance the remaining cost of your system with a solar loan. Many different institutions offer solar loans, from traditional banks and credit unions to the solar panel manufacturers themselves.

How do I learn more?

Visit the Illinois Solar Energy Association website, at, and read these additional resources.
-Department of Energy’s “Homeowner’s Guide to Going Solar”:
-Clean Energy States Alliance’s “A Homeowner’s Guide to Solar Financing”:
– Solar Energy Industries Association’s “Residential Consumer Guide to Solar Power”:

Did you know...
Solar Renewable Energy
Credits (SRECs) allow
solar panel owners to
sell the environmental
value of the power they
produce. You earn one
SREC for every 1,000
kWh produced by your
panels. SRECs are
important to states like
Illinois with laws that
require utilities to get a
certain amount of their
power from renewable