What to Consider when Sizing your New Solar System

There are many items to consider when determining what power output is needed from your new solar system. On top of your energy consumption, you also need to calculate the potential power output for each solar panel.

Luckily for us, Arizona has the second largest potential for solar energy of any state in America. Phoenix has an average of 299 days of sunshine, a whopping 94 days above the national average.

This means residents of Arizona need fewer panels than northern states to make the same amount of electricity. It’s no wonder the solar industry is booming in Arizona.

Below we discuss everything to need to know to determine what size solar project best suits your needs and offer tools as well for the trickier calculations.


Before calculating your electricity needs, you should first consider what energy-saving actions you can make around your home or business. With a few minimal steps you can vastly decrease your consumption, and consequently need a smaller solar system.

For one, you can reduce your energy needs by 20% just by weatherizing your home. Cellulose insulation, for example, can be blown into any space, even enclosed walls and is made from recycled paper that would otherwise be thrown into a landfill.

Another way to drastically reduce your energy consumption is by updating old appliances with high efficiency ones. Did you know a 20 year old refrigerator could use 1,700 kilowatt hours every year while new Energy Star models use only 450 kwh?  

An ultra easy way to reduce the amount of electricity you use is to switch to LED light bulbs. Not only do they use less energy, they also last longer and create vastly less heat. Business owners could consider motion sensored lights, as well.

Related articles: Building a Green Home & How Much Can I Save With LED Lighting?


The next step in calculating the size of your new solar system is to determine the solar potential of your home or business’s location. For this you will consider the typical weather in your region, the surface area available for panels and shade coverage.


As mentioned before, Arizona is one of the best states in the nation in terms of solar potential. This is for a number of reasons.

First of all, solar panels are most efficient at temperatures of 77°F or below. Obviously, hot summer days first come to mind when thinking of Arizona but when you combine the mild spring, winter and autumn months, Arizona’s average temperatures are ideal.  

When you combine that with an average of 310 clear, sunny days a year and that summer days contain up to 13.5 hours of sunlight, it’s clear Arizona is a premier location for those wanting a solar installation.

The reason all this is important is because this translates to your solar panels potentially getting 310 days of unobstructed sunlight for many hours of the day, making you a vast amount of solar energy.

Call our experts today at (866) 204-9886 to help calculate the solar potential in your area.


Lastly, you will need to find the optimal location on your property for a solar installation. The ideal placement of your panels will be in an area that is both large enough and has zero shade coverage throughout the entire day.

In some cases you may need to trim back a tree or two.


Using your last year of electric bills, you can calculate your average energy use. Each month’s bill will show your residence’s or business’s kilowatt hours (kWh) used. Add up each amount for the year and divide by 12 to get your average.

Be sure to subtract any energy savings you may have invested in to lower your electricity consumption. 


To fully understand the size of the solar system you want, you will first need to figure out your budget. For this, make sure to incorporate all of the financial incentives and solar loans available in your area, as well as your net metering options.


The Investment Tax Credit, for example, is a significant federal tax credit aimed to encourage people to use renewable energy. It allows you to subtract 22% of your solar system costs, including parts and installation fees, from your federal income tax.

The state of Arizona also encourages the use of solar power by offering money back for any sales tax paid for parts & installation. It also protects home and business owners from paying extra property tax as your property value rises with solar improvements.

Find more incentives for residential solar systems here and for commercial solar systems here.


A solar project can be paid for in many ways, one most commonly by loans. The first option is the Property Assessed Clean Energy (PACE), sponsored by the Department of Energy to help US citizens make renewable energy updates to the home or business. 

Home Improvement loans are also available through many solar installers as well as your bank or mortgage company.

Another loan to consider is the HomeStyle mortgage offered by Fannie Mae, which allows for clean energy property updates valued at up to 15% of your home or business’s appraised value.

Loans are a fairly common way to subsidize upfront costs of solar installations. Plus any loan you take should see a return on investment as you will save 40% to 70% on your energy bills.


While net metering does not help with upfront costs, it should absolutely be considered when sizing and pricing your solar system. Net metering refers to the practice of the home or business owner selling electricity back to their utility company.

Throughout the day, your solar system will most likely produce more electricity than your home requires. For on-grid systems, you can send the extra energy produced back into the city’s electric grid and the utility company will pay for it.

Each municipality and utility company is unique in their payments and requirements. So the best way to find out specifications specific to your area is to call your utility provider. There is also a large set of incentives and regional guidelines available here.

Related Articles: Upfront Cost of Ownership with a New Solar System[1]  & Tips for Solar Financing


Surprisingly, there is quite a bit involved in figuring out the size of a new solar system. Call us today at (866) 204-9886 and let our experts help find the size that best suits your needs.

Start Saving Today

Electrical Services

Share This