Why You Shouldn’t Use Google’s Solar Panel Calculator as A Solar Quote

Cost Of Solar Panels
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What Google's solar panel calculator actually does

Although a great idea, the Google solar panel calculator isn’t a perfect guide for solar power. The impact residential solar can have on a home takes more than an impressive looking display to find.

Formulas and data specific to the state and utility in the area play a pivotal role in a quality solar calculator. However, this information on its own isn’t enough to give an accurate quote.

The variables that come with each installation make solar calculators best used as a starting point, not as a solar quote. Understanding how Google’s Project Sunroof works helps interested parties know why this program works best towards the beginning of a solar search.

How Google’s Solar Panel Calculator Works

In 2015, Google’s Project Sunroof launched. This program shows people the affordability of residential solar via the Google search engine results pages. 

The user-friendly visual aids help this solar calculator successfully promote solar panel installations. These visuals allow interested homeowners to see the potential savings of solar for their homes.

The features behind these visual aids make it appealing. Some of these include Google’s home images, roof shading technology and solar investment savings calculations.

Google’s Aerial Solar Roof Imagery

Google solar roof imagery technology from Google Maps serves as a base for its solar calculator, allowing the calculator to tailor to individual homes. This program, paired with solar shading technology, gives homeowners an idea of what solar could save them.

Google’s Solar Shading Tech

Google’s Project Sunroof shading technology allows people to see if their home has enough sun for residential solar. If the home has limited sun exposure, the solar panels won’t produce as much power. This program shows people the sun exposure on their roof. It also gives estimated hours of sunlight throughout the year and usable roof space.

Google uses a color gradient to represent spots of the home with higher sun exposure. Purple areas have shading, while yellow ones have greater sun exposure. Homeowners with minimal shading stand to gain the most from residential solar.

Savings Estimates of Google’s Solar Calculator

Google’s solar-cost calculation covers each of the three most common methods of payment for solar. These financing options include cash, lease, and loan.

Default Settings and Assumptions in the Savings Estimate

Although it can adjust, the solar calculator default setting assumes an average monthly utility bill. It then estimates available space to determine the max amount of energy offset a solar array could provide.

Each of these financing options takes into account incentives for the area and the up-front cost of the array. The purchasing option gives an estimated payback period, 20-year benefits, and 20-year savings.

The lease and loan both have the same assumed rate and term of 20 years. They also have an estimated yearly and 20-year cost. These Google solar bases all these calculations on a 2.2 percent yearly-rate increase for the utility company in the area.

Possible Issues With This Solar Panel Calculator

As stated above, solar calculators serve those with a piqued interest in residential solar. If, however, the customer wants to know the viability of adding solar to their home, they need to talk to a NABCEP-certified solar professional.

Solar calculators don’t consider all the factors necessary to give an accurate solar quote. Most solar calculators don’t account for the customer’s monthly energy usage and exact roof measurements.

The tools provided in solar calculators also don’t represent every situation. Considering these calculations as a starting point protects buyers from inaccurate perceptions of savings and solar potential.

Google Shading Tools Compared to Solar Panel Mapping

Designing a solar panel system requires tools that Project Sunroof doesn’t use. Not taking into account these tools makes these calculations less accurate than solar company solar calculators, such as Go Solar Group’s Utah solar savings calculator.

Google Shading Technology Limitations

If a roof doesn’t have enough sun, Project Sunroof assumes the home isn’t a good fit for solar. However, just because a home doesn’t have the needed space doesn’t mean it isn’t a viable option. Homes without sufficient roof space still might have enough yard to install a ground mount.

A Solar Calculator Meant to Educate the Public

When Google first launched Project Sunroof, it informed people about residential solar and why it can financially benefit them. Google later decided to use the tool to generate leads for paying solar companies. The Sunroof Project then switched back to an educational tool in 2017.

Google’s solar calculator serves people better, now that it has stepped away from lead generation. However, this program still struggles to address all the moving variables that make solar panels a good fit for a home. 

Project Sunroof: A Good Place to Start

Project Sunroof lets people know what to expect from a quote. However, it doesn’t replace the price comparison that happens during this process when conducted through a qualified solar installer. Receiving quotes from different solar installers helps the customer determine the best price and product for them.

One of the variables oversimplified in the Google solar calculator is solar financing. Each solar company has different payment programs, products, and pricing, which makes generating return on investment hard for a general solar savings calculator.

Google Solar Calculator Savings Issues

Using a one-option-fits-all can lead the customer to think all solar installers should offer a similar price. However, these estimated prices aren’t realistic for a company with different pricing and product options than the ones in the Google savings calculator.

Differences in Solar Financing 

One area where having a resolute setting becomes a problem is a payment program. Every loan and lease in the Google solar calculator has a 20-year term with a set interest rate. However, each solar company has different payment program options, which would change the savings.

Google Solar Calculator and Company Discounts 

Project Sunroof also doesn’t take into account solar company discounts and customer referral programs. One incentive many solar companies provide includes a cash financing discount.

Cost of Power vs. Power Used

Google and many other solar-savings calculators use average electric bills as a gauge for how much solar would cost. However, sizing a solar array with a utility bill isn’t accurate.

Different Utility Rates

Each utility company has different rates, which makes sizing solar off of the average utility bill a messy process. If one utility charges 10 cents per watt while another charges 12 cents, the monthly bill for the same amount of electricity will cost different amounts. 

Utilities That Provide Both Gas and Electricity

Some utility companies provide both gas and electricity. If the customer doesn’t know what to look for, they may include both in their bill estimate, which would throw off the savings.

The Best Way to Calculate Electricity: Usage

Monthly electric usage of the house over a year will provide the best energy needs estimation. Monthly usage quantifies the electricity used. This measurement stays the same regardless of the price the customer paid that month, making it easier for a solar designer to plan a system that will cover the energy needs of the home.

Using Google’s Calculator and Solar Quotes

Using the Google solar savings calculator isn’t bad. It’s a great place to determine if a home has solar potential. However, it doesn’t have all the answers.

We recommend looking at multiple solar companies, so you can better determine which company provides the best options for your home. If you would like a rough idea of your solar savings with Go Solar Group, we have our own solar savings calculators that take into account, our solar products, and the areas we serve. We also offer customized quotes for qualified homeowners so they can see the solar ROI for their homes.


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