When planning and installing a solar array, you'll also need to consider how much energy storage you need as a backup. This type of backup stores the excess energy your panels collect at peak times and feeds it back into your home's electrical system when the panels aren't catching as much light from the sun. 

Here are some questions to help you decide how much energy storage you need to include in your setup.

1. How much electricity do you use in a day?

Your home's rate of energy use is an important part of the calculations that will determine how much energy you need to store. A typical home uses, on average, around 877 kilowatt-hours per month. However, your energy use may vary depending on your home's size, how energy efficient it is, how many people live there, and the climate. 

If you've used the power grid as your energy source recently, you can check your power bills to see how many kilowatt-hours you typically use in a month. You can use this information to calculate how much you use on an average day. Then, think about your power use habits to find out what the maximum amount of power is that you'll need in a day. For example, if weekends, when you run AC all day and run several loads of laundry, tend to be more power-heavy days, you may need to allow for that as well.

2. How often do you have low-sun days?

Some areas of the country are sunnier than others. While today's solar panels can collect some solar power with light cloud cover, it may not be enough to power your house on. You'll need to have enough energy storage to keep you going through cloudy days.

Check climate data for your region to find out how often you'll have clouds blocking the sun at different times of the year. If your area typically has several heavily overcast days in a row during certain seasons, you may need to plan for that by including extra energy storage.

3. How much do you want as backup in case of emergency?

If your solar array is going to provide 100% of your power, you won't need to worry about the power grid going down. But if you'll still depend on the grid at all, you may want to consider adding extra energy storage to your system in case of power outages, brownouts, natural disasters, and similar emergencies.

These questions can help you fine-tune the amount of energy storage you include with your solar panel installation. If you're not positive exactly how much you need, talk to your solar installation experts about the possibility of adding more later after you've taken your system for a test drive.