How many solar panels do you need to power a house?

The goal for any solar project should be 100% electricity offset and maximum savings — not necessarily to cram as many panels on a roof as possible. So, the number of panels you need to power a house varies based on three main factors: In this article, we’ll show you how to manually calculate how many panels you’ll need to power your home.

What is a solar panel wattage?

Look at different panels and see what the wattages are. The solar panel wattage is also known as the power rating, and it’s a panel’s electrical output under ideal conditions. This is measured in watts (W). A panel will usually produce between 250 and 400 watts of power. For the equation later on, assume an average of 320 W per panel.

How much power does a solar panel produce?

A panel will usually produce between 250 and 400 watts of power. For the equation later on, assume an average of 320 W per panel. Use your annual energy consumption and solar panel rating to calculate the production ratio. You can calculate the production ratio when you have the numbers for your annual energy usage and the solar panel wattage.

How much energy does a 400 watt solar panel produce?

An average 400-watt monocrystalline solar panel will produce 2 kWh of energy per day. Solar panels with higher efficiency ratings will generally have higher wattages and are best for homes with limited roof space. The table below outlines how much energy different types of solar panels produce per month:

How many kW solar panels do I Need?

As we calculated earlier, the California household needs a 7.2 kW system to cover its electricity needs. A comparable household in Massachusetts needs a 9.9 kW system. So, in less sunny areas like Massachusetts, you might consider choosing highly efficient solar panels to maximize your energy output per square foot.

How do I calculate how many solar panels I Need?

You can calculate how many solar panels you need by dividing your yearly electricity usage by your area's production ratio and then dividing that number by the power output of your solar panels. To put it simply: Number of panels = annual electricity usage / production ratio / panel wattage