What Size Solar System Do You Need?

One of the most common questions we receive from our A.M. Sun Solar customers is, “How many solar panels will I need?”

Simply put, the answer is different for everyone. It depends on many variables, such as: How many sunlight hours does your house experience? What are your energy requirements? What solar panel size and efficiency are you considering?

No one formula can calculate the solar system size that is right for your wants and needs.

“There are a lot of formulas, but there’s the human factor that doesn’t fit into a formula,” explained Mark Miller, co-founder and partner at A.M. Sun Solar. “Formulas work if you’re trying to figure out carpeting. You can measure that. But with solar, we’re having to measure usage. And everybody uses power differently, that’s what makes it complicated.”

Your energy usage will vary from your neighbors. Every home or business is unique. Do you run air conditioning more than not? Do you have a large family? Do you drive an electric vehicle? Do you have a hot tub?

“It’s daunting to try to answer the question, ‘What size do I need?’ It depends on how much power you use,” Miller said.

The average-size home in the U.S. (2,480 square feet) uses 10,884 kWh (kilowatt-hours) annually and would need between 15 and 22 400-watt solar panels to replace other energy sources. For most people, a 6-kilowatt system would make about 10,000 kilowatt-hours per year. Kilowatt-hour production is key.

“We are more concerned with how many kilowatt-hours you’re looking to use annually, sizing solar off of that and storage,” Miller said. “Incorporating storage is how you get better economics, and you don’t have to worry about as many blackouts.”

A conversation with one of A.M. Sun Solar’s experienced, in-house designers is more accurate than a formula. We will gladly help calculate your home’s energy requirements and determine how many solar panels you will need for your specific location and house size! We can calculate your average annual use and consumption.

Your custom solar system design will be created especially for you, taking into account such factors as your energy needs, budget, and building structure limitations.

Another thing to consider: The more efficient solar panels you select, the higher wattage of electricity they will produce. That often means fewer panels. Also, panels come in a variety of sizes and weights. The standard 60-cell solar panel measures 39 inches by 66 inches. Most panels weigh approximately 40 pounds each. The number of panels doesn’t really matter, it’s the total system size that does.

A.M. Sun Solar will figure out the best solution to your situation without under producing or over producing.

The Central Coast gets better sunlight than most places in the country. That’s why some of the largest solar arrays in the world are here. It’s no surprise that California’s solar insolation levels rank in the top 10 in the nation. (Solar insolation is the measurement of average daily solar radiation.) San Luis Obispo County is excellent for solar power generation with approximately 300 sun-filled days per year. In comparison, the U.S. average is closer to 200 sunny days a year. Even in the foggy areas along the coast, solar production works well just by adding a few more panels to the west.

Solar panels that receive more direct sunlight convert more energy. The city of San Luis Obispo averages 6.6 fixed-tilt sunlight hours per day (fixed-tilt panels don’t move to track the sun). 

Keep in mind that shade from trees or neighboring buildings can reduce your solar energy production. The angle of your roof matters too. The ideal roof space faces south, west, or east, because they ordinarily see more sunlight. If your roof isn’t perfectly south, for example, you might need more panels. We can also mount solar panels on the ground or on parking structures—not just on rooftops.

Our A.M. Sun Solar installers will measure your house’s roof and accurately ascertain how many panels you will need depending on how much energy you want to harness from the sun.

If you’re ready to make the switch to solar or you’re thinking about adding panels, A.M. Sun Solar offers free consultations! We are no-pressure local people with outstanding customer service. We will come out and explain all of this to you for your unique needs, for free!

Interested in learning more? Fill out the form below to schedule your FREE solar Consultation!

Our team is waiting to talk to you about the best energy solution for your needs. Fill out the form below to schedule your FREE solar consultation!

More about A.M. Sun Solar

A.M. Sun Solar is the local leader in custom solar solutions and installations on the Central Coast. For over 15 years, A.M. Sun Solar has provided high quality, cost efficient solar energy to residences and small businesses in San Luis Obispo, Monterey, and Santa Barbara counties. With a wide variety of financing solutions available, affordable pricing, custom solutions and complete installations from permit to interconnection, A.M. Sun Solar is the go to local solar company on the Central Coast.


Connect with us today at hello@amsunsolar.com, (805) 772-6786, or fill out the form below to get a FREE on-site consultation with one of our friendly solar experts.