In the last few decades , solar panels have enjoyed a surprising surge in popularity. This is partly due to the emergence of environmentally responsible behavior and the desire to reduce energy bills by replacing traditional sources of heating, cooling and electricity with cleaner, more natural sources. If you're considering taking this step, you may be wondering how many solar panels are needed to power your home.
While the answer may be a little complicated, if you hire a professional solar panel installer to consult with you, they will likely handle that part of the process as well (and may even give you advice on how to maintain and clean your solar panels ). .
But if you're wondering how many solar panels you might need and want to take the step of calculating it yourself, you'll need some information: how much energy your home consumes; The amount of available roof space that can be used to house solar panels, the number of hours of sunlight your home receives , and the relative power and efficiency of the solar PV panels you plan to install .
How to determine the need for solar panels
To calculate how many solar panels you need to power your home, you'll use a formula that includes three main factors, according to EnergySage: annual energy use, panel power, and percent yield. but what does that actually mean?
Annual electricity consumption
The first step is to determine the annual electricity consumption; This is the amount of electricity your entire house uses in one year. This number, measured in kilowatt-hours, includes all sources of electricity in your home, including large and small appliances, air conditioners, lights, air purifiers , and water heaters . The US Energy Information Administration (EIA) reports that the average home uses about 11,000 kWh of electricity annually.
solar panel power
When choosing the best solar panels, you might think they look almost the same, but they're not built exactly the same, so you need to know the wattage of the panels you're going to install. The watt of the panel is the amount of electricity that the panel produces. Most solar panels are rated between 250 and 400 watts, so it's safe to assume that 300 watts is the average wattage of a panel you're likely to encounter.
production factors
According to EnergySage, the power factor of a solar panel system is the ratio of the system's rated power over time (in kWh) to the actual system size (in watts). You might think it's a 1:1 ratio and you get what you put in. But the difference in the amount of sunlight passing through your home means no.
A 10 kW system that produces 16 kWh of electricity per year will have a production factor of 1.6 (16/10 = 1.6). A place like Hawaii, with its long days and constant sunshine, is very likely to get that ratio, while cloudy and rainy New England might have an average harvest of just 1.2.
Calculate the number of solar panels needed
This is the actual formula used by EnergySage that you can use to determine how many solar panels you will need:
- Number of panels = system size/factor of production/panel capacity
- Using the numbers we've determined so far, we get:
- Number of panels = 11000 kW / 1.6 / 300 W
That's the equivalent of about 20-25 solar panels to get the job done. You can use the same formula to determine how many solar panels you need to power your home. Or you can take the easy route by looking at your electric bill to determine what you need.
An alternative way to learn about using solar energy
If you're not interested in doing your own bills, take a look at your utility bill to see how much energy you use. This lets you multiply your energy use by the number of hours of bright sunlight your home gets, and then divide the result by the watts of panels you plan to install.
Factors that influence how many solar panels you will need
Is there anything else to think about besides the calculations above? As it turns out, there are many other factors to consider when determining how many solar panels to power your home.
Solar panel performance efficiency
Solar panels will not receive energy from the sun at full capacity all the time. Think of the three days of rain that falls in autumn, or the heavy winter snow that melts in a few days. This is when you need a buffer for your energy use, so it is recommended that you get about 25% more solar panels than you need.
sunny hours
The amount of energy you get from solar panels is directly related to the amount of sunlight your home receives. More panels will be needed if you live in an area that doesn't get strong sunlight for long hours.
The power of your panels
Most solar panels range from 150 to 350 watts per panel. If you choose a lower wattage panel, you'll need more to generate enough power for your home. Of course, this assumes you want to replace 100% of your energy use with solar energy . If you're only hoping to do a partial conversion, the difference in solar panel output probably won't matter much.
Solar panel cost.
How much do you want or plan to spend on solar panels ? Before buying, make sure you know how many items will fit into your budget.
solar panel size
To find out how many solar panels you'll need, you need to know the standard solar panel sizes so you know how many panels you can fit on your roof. A 60-cell residential solar panel is 17.62 square feet, and a 72-cell commercial solar panel is 21.13 square feet. Solar panel installers measure the roof area to determine how many panels can be safely installed.
