Can a solar system power a house? Yes! But how many solar panels to power a house? The answer depends on several factors: how much energy your household or business consumes, where you live, the type of panels used, etc. Let’s take a further look!
Knowing Your Energy Needs
Today’s solar panels are far more efficient, even when compared to panels from a decade ago. Before you decide anything else, you need to know just how much energy your home consumes. According to the US Energy Information Administration (EIA), the average American household consumes about 11,000 kilowatt-hours (kWh) per year. However, it’s important to know that this amount can vary greatly from state to state, and even by region. For example, southern states tend to have higher energy household consumption rates, while Colorado averages 8,400 kWh according to the EIA.
To learn the annual energy consumption of your home, check your utility bills.
Solar Panel Energy Output
Will a solar system be able to handle your home’s energy requirements? Let’s look at how much energy a solar panel generates. In ideal conditions, which is direct and unfiltered sunlight, the best solar panels have an average power output rating of 250 to 400 watts per hour. This means that the panel will produce about 2.5 to 4 kWh of energy per day.
Peak Sunlight Hours
You will also need to know the daily average amount of sunlight where you live, or peak sunlight hours. This varies from region to region. For example, Colorado receives an average of 6 peak sun hours a day. Remember, solar panels only produce electricity during the day.
You will also need to know the production ratio of the solar panel system you are considering. Production ratio is the ratio of the system’s estimated energy output over time in kilowatt hours (kWh), in relation to the actual system size in watts (W). This ratio is almost never 1:1, and this ratio will change depending on the amount of sunlight you receive where you live.
An example: a 10 kwH system that produces 13kWh of electricity annually has a production ratio of 1.3. This is calculated by taking 13 and dividing by 10 = 1.3 Most solar systems in the US have a production ratio between 1.3 to 1.6.
How To Calculate How Many Solar Panels For A House
You will need to know these 3 factors when calculating the number of solar panels needed to power your home:
1. Know your annual electricity usage
2. The output, or wattage, of the panels you are considering
3. Estimated production ratio of your solar power system
Here is the formula:
Number of panels = system size / production ratio / panel wattage
Let’s use a 400-watt solar panel as our example.
Number of panels = 11,000 kWh / 1.3 to 1.6 production ratio / 400 w
So, you’ll need between 18 to 22 panels in a solar array to power your home. The amount of panels depends on the production ratio of the system:
22 panels for 1.3 ratio system
18 panels for a 1.6 ratio system
To calculate system size, simply multiply the number of panels by the wattage:
22 panels x 400 watts = system size of 8.8 kW
18 panels x 1.6 watts= system size of 7.2 kW
FAQs About Solar Panels
Now that you know how to calculate how many solar panels for a house, let’s take a look at several frequently asked questions about solar panels.
Are there different types of solar panels?
Yes. The are three main types of solar panels:
Monocrystalline: Monocrystalline panels are made of one large silicon crystal. These are the most efficient in generating energy. They are usually the most expensive.
Polycrystalline: These panels are made of several smaller silicon crystals melted together. These panels produce about 1% less power than monocrystalline panels. However, these panels are still reliable and are the most common type of solar panel.
Amorphous: Amorphous panels are composed of non-crystalline amorphous silicon. These panels are the easiest to install and are usually the cheapest option. The downside: they have the lowest power yield of the three solar panel types. These panels have an all-black, sleek design.
How long do solar panels last?
With proper care and maintenance, solar panels can last about 25 years. Several factors will affect their lifespan:
Location: High humidity, constant direct sunlight, and salt air can make panels age faster.
Panel Quality: cheaper panels will need to be replaced more often.
Weather: sever weather conditions, such as hailstorms, high winds, and hurricanes can damage panels, leading to decreased energy output or need for replacements.
How can I optimize the output of my solar panels?
Keep your panels clean, as any dust or debris can decrease energy output. Fortunately, solar panels are relatively easy to maintain. Rain and snow help keep panels clean, especially if the panels are tilted. Leaves and bird droppings should be removed. To avoid electrocution, always power off the system first before cleaning your solar panels. Avoid harsh chemicals and use a gentle soap and soft brush to clean the panels. Only clean the panels on cooler days.
Other than being clean energy, what is another advantage of solar power?
Solar power is energy you own. Compare this to utility electric, in which you pay to “rent” or use the electric company’s energy to power your home.
It is entirely possible to power your home with solar panels. Knowing how to calculate the number of panels needed can help you better understand energy requirements and how solar panels generate power. As always, Atlasta Solar Center is here to help you find the solar solution that’s best for your needs. We will calculate how many panels your home will need, as well as discuss factors such as location, tilt, and type of panels. Call us with any questions, or for a complimentary solar site analysis, at (970) 248-0057.