How Many Solar Panels to Power a House in Santa Rosa, CA?

Offset Your PG&E Bill with Solar Power for Your Sonoma Home

Many modern homeowners find themselves asking the same question: how many solar panels does it take to power a house in Santa Rosa? While energy bills in Sonoma County keep rising, solar energy is one of the most reliable ways to cut these costs. The number of panels you need, however, depends on how much power your home uses, the size of your roof (where the panels are installed), and the type and size of the solar panels you install.

Don’t have a clue? Not to worry! This guide explains the basics so you can understand what size solar system is right for your home. Start with understanding the energy your living space requires and go from there.

Understanding Your Home’s Energy Needs

The first step is looking at your electric bill. Energy use is measured in kilowatt-hours (kWh). Study it closely for a couple of months to get an accurate measurement of your average use. A smaller home, for example, might use 600 kWh per month, while a larger home could use 1,000 kWh or more. The more power you use, the larger your solar system size needs to be to live comfortably.

Key factors that affect energy needs:

• Home size: Bigger homes need more power.
• Appliances: Electric water heaters, dryers, and EV chargers raise usage.
• Lifestyle: Working from home or running AC all summer adds more kWh.

Many homeowners in Sonoma County average 700–900 kWh per month. Knowing your own house’s consumption helps you and your solar installer figure out the number of solar panels you need.

Solar Panel System Size, Explained

A solar system is measured in kilowatts (kW). The number of kilowatts used tells you how much power the solar system can produce in ideal sunlight.

• A 5 kW system may cover 500–750 kWh per month.
• A 6 kW system may cover 700–1,000 kWh.
• Larger homes often need 7–10 kW.

Santa Rosa gets about 260 sunny days a year, which makes solar energy a strong and sustainable choice. For example, if your home uses 900 kWh each month, you may need a 6–7 kW solar system. A local solar installer can check your roof, shade, and energy bill to size the system correctly.

You can read more about solar panel placement on our blog.

Calculating the Number of Solar Panels Necessary

It isn’t complicated for you to figure out the number of solar panels if you use a simple formula.

Formula:
(Monthly kWh ÷ average daily sun hours ÷ panel wattage) × 1,000 = number of panels

Example:

• Your Santa Rosa home uses 900 kWh per month.
• Divide by 30 days = 30 kWh per day.
• Santa Rosa averages about 5 sun hours a day.
• Panels often produce 400 watts each (0.4 kW).

30 ÷ 5 = 6 kW system.
6 kW ÷ 0.4 kW = 15 solar panels.

That means the number of solar panels you need may range from 15 to 20, depending on the size and type of panels. A solar panel calculator, or a solar panel size estimator, can give you a rough estimate, but a professional check is best.

External Factors That Affect the Number of Solar Panels

Several things can change how many panels you need:

1. Sunlight
   Santa Rosa and Sonoma County have strong solar potential, but cloudy days or winter months can lower output.
2. Roof space and angle
   South-facing roofs work best. Shading from trees or tall buildings may mean more panels are needed.
3. Energy efficiency
   A well-insulated home with LED lighting and efficient appliances may need fewer panels to meet the same demand.
4. Future needs
   If you plan to charge an EV or add more space to your house, it makes sense to plan for a larger solar array now.
   Each home is different, which is why a site visit from a professional installation company matters.

Incentives and Financial Considerations

The cost of installing a solar energy system has dropped significantly in the last decade, and incentives make it even more affordable for Santa Rosa residents. Plus, we offer reasonable financing for qualifying homeowners.

• Federal Solar Tax Credit: Covers 30% of installation costs.
• California Solar Incentives: Net metering allows you to sell extra power back to PG&E.
• Local rebates: Sonoma County may offer programs for energy upgrades that pair with solar panels.

The average cost of a solar installation in California is $2.50–$3.50 per watt. A 6 kW system costs $15,000–$20,000 before incentives. With the tax credit, you save about $4,500–$6,000.

Energy bill savings often range from $1,000 to $2,000 per year. Many homeowners recover their upfront cost in 6–8 years. After that, the system keeps producing power for decades.

How to Calculate Solar Panels for Your Home and Save with Solar in Sonoma County (FAQs)

Go Solar Today and Start Saving with Solar Power in Sonoma County

Ready to take control of your energy consumption and embrace clean energy? Go solar with a custom solar power system tailored to your home’s needs. Now that you know how many solar panels to power a house in Santa Rosa, the next step is a custom plan for your home. Suntegrity Solar has installed over 1,000 systems across Sonoma County. Our in-house team designs solar energy systems that cut your energy bills and add value to your home.

Get started today and learn how you can reduce your energy usage and take advantage of rebates and incentives. Call (707) 623-1464 today or visit our solar installation page to schedule your free consultation.