How Many Solar Panels To Power A House

There are numerous benefits to going solar such as saving on utility bills, earning tax credits for putting energy on the grid, helping the planet reduce its reliance on fossil fuels, etc. So are you thinking about adding solar to your house? It’s no use installing just one solar panel. You’ll need more than that to reap the financial benefits of a solar panel system. While the answer isn’t always so simple.

We’ve been working in the solar industry for over 11 years and have helped thousands of families (residential rooftops) adopt solar to fully offset their electricity bills. In this short article, we’ve put together example cases to help you understand, at a high level, how many solar panels you need to install an effective solar array.

How Many Solar Panels Do you Need?

The actual number you’ll need to install depends on three key factors: annual power usage, panel wattage, and production ratios.

Black Solar Panels, Rooftop Solar Systems

First, Annual Power Usage

Your annual power usage is the amount of energy and electricity you use in your home over a full year. Measured in kilowatt-hours, this number is influenced by the appliances in your home that use electricity and how often you use them. A simple way is to look into your latest 12 months’ electricity bill and simply add them together. For example, my annual power usage is around 6000kWh. Once you have this data, feel free to plug it into the equations below.

Second, Solar Panel Wattage

Also known as a solar panel’s power rating, panel wattage is the electricity output of a specific solar panel under ideal conditions. Wattage is measured in watts, and most mono solar panels fall in the range of 330 – 550 watts. We’ll use 460 watts as an average panel in our calculations because this model is among the most popular solar panels on the market today.

10kW Solar System Output, 10kw solar system calculator

Third, Production Ratios

A solar panel system’s production ratio is the ratio of the estimated energy output of a system over time to the actual system size. This data depends on how much sunlight your solar system gets, which is primarily based on geographic location, and the direction and angle of solar panels. For example, a 10 kilowatts system that produces 11 Megawatt-hours of electricity in a year has a production ratio of 1.1 (divide 11 by 10 equals 1.1). This is an entirely realistic production ratio to see out in the real world.

Finally, Do Out The Math

Now we know the power usage, solar panel wattage, and production ratio. How to work out an estimated number of solar panels? The formula looks like this:

Power Usage / Production Ratio / Panel Wattage

Fill in our data: 6000 / 1.1 / 460 = 12 pieces.

12 times 460, it’s a 5.5-kilowatt solar panel system.

How Many kWh Can The Solar Panel System Produce?

The amount of power (kWh) your solar panel system can produce depends on how much sunlight it receives, which in turn creates your production ratio. The amount of sunlight you get in a year depends on both where you are, and what time of year it is. If you live in a place that gets fewer peak sunlight hours, you’ll need to have a larger solar panel system installed. Also, there’s always a big power difference between Summer and Winter.

Factors Increasing Number Of Solar Panels

Even the most premium solar panels don’t work at their rated power. There are some factors for consideration.

Solar Power Output, Solar Irradiance, Solar Insolation, Orientation, angle of inclination
  • Shadow: The biggest enemy of solar panels is the shadow. Objects nearby the solar panels like buildings, trees, poles all cast shadows on the solar panels which hamper the generation. So the solar panels should be placed in such a place where there’s no or little shade.
  • Orientation: Ideally solar panels should be oriented towards the equator. If you live in a country that falls in the northern hemisphere like China, the USA, India, then your solar panels should be facing the south, and vice versa.
  • The angle of inclination: The angle of inclination from the ground also plays an important role in power generation since the position of the sun changes all year round. So it’s necessary to select an angle for the best generation throughout the year. Usually, using a tracker system that follows the sun path can help gain more power.
  • Dust & snow: Even the best solar panels will fizz out if there is a thick layer of snow or dust. Dust and snow prevent the sun rays from hitting the cells, which will severely reduce electricity generation.

More About PV

Black Solar Panels for Rooftop Solar Systems

The Black monocrystalline module is a sleek and robust module with excellent build quality and performance. Coulee started offering all-black modules years ago for customers that had aesthetic concerns, and now they’re part of our standard offerings. We pitch ourselves as a company that installs premium products and refuses to sacrifice quality. Part of that is offering the best-looking modules possible.

Leave a Comment

Your email address will not be published. Required fields are marked *

Free 'Solar Power Your Home' E-book

Written by Rik DeGunther, providing you with an ample solar knowledge base and let you apply it through DIY projects
best Mono Solar Module Manufacturer Popup
Open chat
Need help?
Can we help you?