How Many Solar Panels Do I Need? A Californian Pro Explains

By Your Advisor 7/26/21 11:03 AM Time to read:

When planning for a solar energy system, one of the first questions homeowners ask is how many panels they need to completely power their homes.

Here’s the short answer: Based on state averages, most homes in California will require 8 to 20 solar panels

Of course, that range is just a general estimate. If you’d like an exact answer, it’s best to contact a solar energy expert. They can accurately calculate how many panels will sufficiently power your home.

In this blog, we’ll cover:

  • How to estimate the number of solar panels your home will need
  • Why a professional should determine the number of panels for your home

Want help sizing your solar energy system? Burgeson’s can help!

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How to estimate the number of solar panels your home will need

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In the beginning, we mentioned most homes in Southern California will need 8 to 20 panels, but that number could easily go up or down depending on your home’s energy efficiency, power usage and the panels you choose. 

We’ll walk you through the steps on how to get a better estimate for your home.

Step #1: Find your annual household power consumption

In California, the average annual energy consumption per household is about 7,000 kWh (kilowatt-hours). However, that number could be different for your home.

To find how much power your household consumes each year, look at your electrical bill from December of the previous year. At the bottom of the bill your electrical provider typically shares how much electricity your home used in kWh throughout the year.

Step #2: Determine the wattage of the panels

The wattage of a solar panel expresses how much power it produces. Solar panels can range from 150 watts (low) to 370 watts (high). A 250-watt solar panel is considered average. 

The wattage of a solar panel should be clearly advertised and easy to find. In fact, most solar panel manufacturers indicate the wattage of a panel in its name. For example, the Amerisolar AS-6M30-250 is a 250-watt panel.

Step #3: Account for the low and high solar panel production ratios

Now we need to account for the efficiency of the panels by looking at their production ratios.

A production ratio is the estimated number of kWh a set of solar panels will produce in a year, divided by the wattage of the panels. The higher the ratio, the more efficient the panels. 

In California, the typical solar panel production ratio range is 1.4 to 1.8.

Step #4: Crunch the numbers

After following Steps 1–3, you should have the following numbers:

  1. Your home’s average annual energy consumption (kWh)
  2. The wattage of the solar panels you intend to use
  3. The typical solar panel production ratio range (1.4 to 1.8 in California)

Here’s how to do the calculation:

  • First, divide your home’s average annual energy consumption (kWh) by the wattage of a solar panel.

 

  • Next, divide the answer from above by each production ratio (1.4 and 1.8). This will give you a more accurate range for the number of solar panels your home will need.

Of course, this range is still a rough estimate. If you want to know exactly how many panels you need for your home, you’ll need to contact a professional. We’ll explain why below.

Want a professional to help you size your solar energy system?

Sizing a solar energy system is complex. Beyond the items discussed in the steps above, there are so many other factors that impact the scope of your solar panel project.

Other factors that determine the size of a solar panel system include:

  • The size of your roof
  • How much shade your roof gets
  • The tilt of the panels 
  • The capacity and depth of discharge (DoD) of the battery
  • And more

Because these factors are difficult to calculate on your own, it’s best to let a solar energy expert help you determine how many solar panels you need. 

If you’re looking for a solar panel expert in the Inland Empire, we’re happy to help. Our team of solar energy experts can quickly help you determine how many solar panels you need for your home.

REQUEST APPOINTMENT