Sunny Corner Home with solar

Is my house suitable for solar panels? Factors that affect your home’s sun number score

A Sun Number Score is a helpful tool for gauging how well your home and its location suit a solar panel installation. Learn more here!

While a “Sun Number Score” might not strike a bell for everyone, it’s a familiar term for those looking to acquire solar panels. The company Sun Number, which focuses on elevating public awareness of buildings’ solar potential through a scoring system, created the Sun Number Score. Its online platform allows you to enter your address to determine your score while also learning the amount of energy you could save by going solar. A number of factors determine your Sun Number Score — let’s look at what they are.


A Sun Number Score is a rating between 0 and 100 that represents your home’s solar power potential. With 0 being the lowest and 100 the highest, the higher your Sun Number Score is, the better suited your home is for generating solar energy.

House drawings with numbers representing the solar potential of the house


Sun Number Scores are important because they represent the viability of adding solar panels to a building. That’s essential information for both homeowners considering solar energy and people looking to buy a home and install solar panels.

While square footage, yards, decks, multiple stories and more are factors that many consider when buying a home, people are increasingly requesting Sun Number Scores. Zillow now lists this score for around 84 million homes. Overall, it’s become vital information to provide homebuyers.

Higher scores also represent greater potential electricity savings as well as higher property value. The latter’s especially true if homeowners plan to sell or rent their home in the future.

70% sun rating score


The Sun Number Score scale ranges from 0 to 100. A score of 70 or higher is considered a great score. If your score is 70 or above, adding solar panels to your home is a wise decision which should generate long-term financial savings

While rare, a score of 100 means your home is perfect for solar panels. It really couldn’t get any better. 

Almost no homes qualify for a perfect score, but that doesn’t mean solar panels won’t suit your home. Even if your score is below 70, you may still benefit from a home solar installation. However, it’ll have a lower energy output. 

And if your score is lower than average, your system might just require a more complex solar panel design to absorb as much sunlight as possible. Meanwhile, an above-average score doesn’t necessarily mean you need to install solar panels. But it’s a great feature to note if you plan to sell your house in the future. Homes with higher scores typically have higher property values because they usually have existing solar panel systems. 

sun number


Four factors influence your total Sun Number Score: a building score with a maximum of 80 points, a regional climate score with a maximum of 8 points, an electricity score with a maximum of 8 points and a solar cost score with a maximum of 4 points.


Roof slope, orientation and size determine your home’s building score. It’s best to have a building score no lower than 50.A score above 60 is considered a great score for your home’s solar power potential.

The more area your roof has to support and install solar panels, the better. Additionally, the direction your roof faces is important. South-facing roofs will see the most sunlight and generate more than enough solar energy to power a home. There’s higher potential for excess energy production, too. You can store excess energy in a solar battery. Alternatively, excess energy can return to your city’s grid, and you can redeem credits. 

Roof slope is also important. Solar panels function best at a 30-degree angle. If your roof slope is less or more, tilt brackets can tweak your pitch per the roof’s steepness and positioning.

[Related: What Is the Best Roof for Solar Panels?]


The area surrounding your home plays a role in your Sun Number Score as well. If your residence is in a shaded area with many trees, buildings or other sun obstructions, your score can be lower

Climate and weather conditions can affect your score, too. Does your region have a higher number of sunny days than others? For example, Colorado sees around 300 sunny days per year, making it an ideal location for high solar power potential. However, areas that experience numerous overcast days aren’t doing your score any favors. 

To calculate your home’s regional climate score, Sun Number relies on solar irradiance data from the National Renewable Energy Laboratory (NREL).


Sun Number considers the average electricity rates in your area to determine how beneficial solar panels are for your home. 

Because solar panels save you money on electricity over a lifetime, the higher the electricity rates in your area, the higher your score. In areas with lower electricity rates, you won’t see much or any increase in your score. 


Local costs for solar installations have an inverse effect on your Sun Number Score compared to local electricity rates. The lower the cost is to install solar panels in your area, the more points you gain on your score. Higher installation costs do the opposite. 

[Related: Average Cost of Solar Panels and Installation]


Whether your Sun Number Score is on the low or high end, you’ll likely benefit from speaking with a professional. With assistance, you can weigh your options for a commercial or home solar installation.

Looking to maintain, repair or upgrade your solar system? Our solar repair and maintenance service department can help you obtain maximum energy production and efficiency.

For more information on purchasing and installing a solar panel system or to discover your home’s solar potential, contact solar panel company Freedom Solar. Call (877) 795-0577 or submit an online inquiry today!