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Frequently Asked Questions



We want going solar to be an easy decision for you.  We realize you have questions.  The best way to get answers is with a free quote.  But, on this page are are some of the questions we are asked most frequently.  We also have in-depth articles about solar on our blog.  For anything else, please fill out our “Contact Us” form.

Is my home a good fit for solar?

Most owner-occupied single family homes not excessively shaded by trees or other buildings are good candidates for solar.  Ideal homes have south-facing or flat roofs, but east- and west-facing roofs also work.  The best way to find out if your house is a good fit for solar is to get an expert opinion.  Contact us for a free consultation about whether solar makes sense for you.  We also have a detailed page focusing on this topic.

How big of a solar system do I need?
It depends on how much electricity you consume and the amount of that electricity you’d like your solar system to produce.  The size of your roof will also impact the size of the solar system you can have.  In the solar industry, we use “kilowatts” to measure the size of a system.  Most single-family homes can produce 80-100% of the energy they consume with a system between 4 and 10 kilowatts.

Contact us for a free, no-pressure consultation and quote.

Is the Midwest sunny enough for solar?

Yes.  Although Illinois and Wisconsin don’t receive as much sunshine as California or Arizona, the price of solar equipment has fallen so much in the past few years that solar is now a good investment in these states.

How much does a residential solar system cost?

The number of panels in a solar system is the biggest driver of cost.  Systems with more panels are more expensive than systems with fewer panels.  However, federal and state incentives can cover a significant portion of the cost.  We also have financing options available.  Learn more about solar system costs and financing options here. We are happy to provide a free, no-pressure quote.

What incentives for solar are available in Illinois?

Both the federal government and Illinois provide incentives for home solar.  The federal incentive is a tax credit worth 26% of the cost of the system for systems installed in 2021.  It declines to 22% for systems installed in 2023.  With it, you reduce the income tax you would otherwise pay by this amount.  Click here for more information on how to take the credit.

The Illinois solar incentive comes in the form of Solar Renewable Energy Credits (“SRECs”) you earn with your system.  Most Illinois utilities are required to purchase these from you (at prices set by the Illinois Power Agency) when you install your system.  They are typically worth about 30% of the cost of a typical system.  You should receive your SREC payment check within six months of energizing your system.

What incentives for solar are available in Wisconsin?

Customers of most Wisconsin utilities, including We Energies and Alliant Energy, are eligible for the Wisconsin Focus on Energy rebate when they purchase a qualifying solar panel system.  This Wisconsin solar incentive is worth $500 per system.

How much money will I save by going solar?

The amount you will save depends on how much electricity you consume today, the size of the solar system, the utility from which you receive service, and several other factors.  Your solar consultant will answer this question specifically for your home during a consultation.

How long does it take to have solar installed?

On average it takes about 90 days, with the actual physical installation taking on average 1-2 days.

Our first step is to apply for permission to interconnect your system to your utility (“interconnection”) and for you to receive credit for any energy you send back to the grid (“net metering“). Most utilities take between 4-12 weeks to approve these applications.

At the same time that we apply for your interconnection and net metering, we will file to secure your state incentives. This ensures your incentive money is available to you as soon as possible.

Our next step is a detailed site assessment. We will reach out to you to schedule a time to come to your house so we can take pictures and gather information vital to the system engineering and installation process.

With the information gathered at the site assessment, we create detailed construction drawings. We will use them to get the required permits and, if necessary, get approval from your homeowners association.

Once the system is engineered, we apply for any building permits required by your municipality. Every municipality has different requirements, so our expert team will put together a custom package to receive approval as quickly as possible. Depending on where you live, this could take as long as 4-6 weeks.

When all the above steps are complete, we are ready to install your system. We will coordinate with you to schedule installation on a day that is convenient for you. Home solar installation takes one to three days, depending on the size of your system and the complexity of the project.

Once we complete your home solar installation, we arrange for an inspection by your municipal inspector.  In some cases, we may need an additional approval from your utility.  Once we have these approvals, we are ready to turn on your system.

As soon as we turn on your system, you will start saving money and producing 100% renewable energy.  For most homes, this is 60-120 days after you accept our proposal.

Will solar panels damage my roof?

No. We guarantee our installations will not cause any leaks.

Will my system include batteries?

Generally, no. Most home solar systems are designed to operate in conjunction with the electric grid.  That way, if you happen to consume more power at any moment than the solar system is producing, you draw the excess power from the grid. Conversely, when your solar system produces more than you are consuming at that moment, the excess power will flow into the grid. Your utility will net out all of this and you will only be billed for the net amount you consume from the grid.

If you’re interested in learning more about energy storage, please ask your solar consultant.

How long will a solar system last?
Our equipment comes with a 25-year labor and materials warranty.  Its expected life is about 40 years.  You should expect your solar system to reduce your utility bills and produce clean energy for many years into the future.
What kind of maintenance is required?
Little to none.  Solar systems are totally electronic and have no moving parts.  Furthermore, we only sell equipment with 25-year warranties.  If your panels get excessively dirty, it may make sense to clean them (which we can do for you), but this is not usually required.
Do you provide a warranty?
Yes!  All of the equipment we install on your roof comes with a 25-year parts and labor warranty.
What if I want to sell my home?

Research has found that solar panels can increase home values.  Lawrence Berkeley National Laboratory (a unit of the U.S. Department of Energy) issued a report in 2015 showing that homes with solar sell for more than similar homes that do not have solar.  In fact, they found that the increase in sale price was greater than the net cost of the solar system.  Other research has reached the same conclusion: having a solar system increases your home’s value.

What areas do you serve?

Northeastern Illinois and Southeastern Wisconsin.

How does the Certasun referral program work?

Through the Certasun referral program, if you refer a friend, family member, or acquaintance to Certasun and they install a solar system through us, Certasun will pay you $500.

Certasun will pay you the $500 once your referral’s solar system is installed and paid in full.  Please note that referrals are processed once per month and so it might take a few weeks after your referral’s installation before your receive your payment.

Side note: If you make the referral through the Certasun App (available for iOS and Android), we’ll prepay you $25 of the $500 once we’ve delivered a proposal to the referral.

Why isn't my solar system producing what I expected?

First question: Are you measuring production in kilowatts (kW) or kilowatt-hours (kWh)?  kW are the measure of the instantaneous power of the system.  kWh are the measure of the energy produced by the system, which replaces the energy you would have otherwise bought from your utility.

If the kW output of the system is less than the nameplate capacity of the system (nameplate means the kW that were installed / contracted), that’s perfectly normal.  Solar systems only produce close to their nameplate capacity during midday in summer months when the sun is shining directly on the panels.  In winter, on cloudy days, or in the evening, the kW output of the system will be much lower than its nameplate capacity.

If the kWh output of the system is less than expected, this may be due to seasonal variation.  In other words, if your system became operational on December 1, we expect its first month of production to be significantly less than 1/12 of its estimated annual production.  December includes the shortest day of the year and often features overcast weather.  None of this is ideal for solar production.  Conversely, if your system became operational on June 1, we expect its first month of production to significantly exceed 1/12 of its estimated annual production.

Whenever you measure the kWh production of the system against expected production, you need to do so over a sufficiently long time horizon to overcome seasonal variation in insolation (how sunny it is).

All that being said, occasionally a system does produce less than expected for reasons that aren’t explained by insolation.  Please don’t hesitate to contact us if you believe your system is underproducing in a way that can’t be explained by the factors described above.



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