How Many Solar Panels and Batteries Do I Need for My Home?

When considering solar for your home in Monterey, Santa Cruz, or Salinas, two big questions come up: How many solar panels do I need? and How many solar batteries does my home or business need? At Premo Solar, we install premium residential and commercial solar panels and battery backup systems that can help you take control of your power.

Let’s dive into the details about Solar panels first and then move onto batteries!

Your Electricity Bill

The first step is to determine the electricity consumed by your household. For best results, try to calculate the electricity consumption in one year. If your electricity bill does not fluctuate wildly, you may also get the kWh figure by looking at your monthly bill.

According to the U.S. Energy Information Administration, the average residential customer in the United States uses 10,649 kWh a year. The figure translates into 877 kWh per month. You can find the required kWh figure in your latest energy bill. If you can’t find the kWh reading, subtract the previous reading from the current reading.

For the sake of this article, let’s assume that your average electricity bill is 900 kWh per month. 

Due to variations in peak sunlight hours in Winter and Summer, it’s practical to calculate your monthly electricity bills based on an average for 12 months. It makes sense because you don’t want to end up with low or very high estimates. 

The Output of the Solar Panel

The third critical factor that determines the number of home solar panels is the solar panel output. There is a wide variety of solar panels in the market ranging from 200 kWh to 370 kWh. The average solar panel has an output of 265 kWh per panel. 

The final output produced by a solar panel depends on efficiency. Under normal conditions, solar panel efficiency of 15% with one square meter produces 150 watts. For this discussion, assume that the output of a solar panel is 300 watts per panel.

Here is the formula for calculating the number of home solar panels you will need:

Number of solar panels = Energy Your Home Needs/output per panel

= 5580 watts/300 kWh per panel 

= 18.6 solar panels.

A typical home needs between 20 and 25 solar panels to offset the entire electricity bill of an average home. However, a solar contractor can also give you a better idea after inspecting your premises.

Here is a recap:

1. Calculate the kWh per month.
2. Calculate the amount of sunlight per day in your location.
3. Plug these two figures in the formula: Amount of Energy Your Home Needs = kWh / daily sunlight x 30.
4. Convert the result to watts by multiplying the result by 1000.
5. Determine the output per panel for your desired solar panels.
6. Use this formula to find the number of solar panels:
   Number of solar panels = Energy Your Home Needs/output per panel.

Benefits of Solar Battery Backup

Solar batteries store the excess electricity that your solar panels generate during the day so you can use it when you need it, like when the sun isn’t shining. This comes with several benefits, including:

• Energy independence – Solar panels are great on their own, but adding a battery backup system further reduces your reliance on the grid and protects you from ever-rising electricity rates.
• Blackout protection – Avoid losing power during an outage or PSPS and keep the lights on when you need them most with a solar battery backup system. 
• Utility bill savings – You won’t have to worry about high electricity bills at night when your panels can’t produce power because battery backup systems allow you to use stored energy at any time. Time-of-use rates are at their highest in the evenings, and switching to stored energy during these times can save you money. 
• Available for incentives – Solar batteries are eligible for incentives that can help make installation more affordable. For example, home and business owners can save 30% of the total cost of installing a solar battery with the federal solar tax credit. 

How Many Solar Batteries Do You Need?

It’s completely possible to power an entire home or building with solar panels plus battery storage. However, there are several factors to consider when you want to figure out how many batteries are needed to power a house or business. 

At Premo Solar, our process for calculating how many batteries you’ll need is similar to the one we use when determining the right amount of panels. Unfortunately, there’s no real rule of thumb to go by with solar batteries because every home and building is different. However, here is what our team of solar experts will look at:

• Energy usage – One of the most important things to take into account is how much energy your home or business uses. This will equip our team to make recommendations on which size battery, and how many, will meet your needs. 
• Solar panel generation – Solar batteries can only store as much electricity as your panels generate. If you want to run your entire home or business on solar energy, you’ll need to make sure that your panels have the capacity to produce as much as you’ll need. 
• Storage capacity – Not all solar batteries will hold the same amount of electricity. For example, Tesla Powerwall batteries can store 13.5kWh, but the average California household uses 20kWh per day. This means two batteries would be needed for full backup. 

Premo Solar: Your Local Solar Panel and Storage Experts

We believe that solar batteries are worth the cost and can help you maximize your savings with solar energy and get the most out of your panels. We only install the leading brands in the industry, like Tesla Powerwall and Enphase. Whether you’re looking to add battery storage to your current solar system or want to install solar panels and battery backup all at once, our team is here to help. Premo Solar has been in the solar industry for many years and our team will handle everything for you, from permitting and applications to the final inspection.

Get solar panel system and battery backup today. Call 831-901-3352 or contact us online for a free estimate.