If you have ever considered buying solar for your home, you’ve probably spent hours researching how much solar panels can save you and your family on your monthly electricity bill. While it is important to understand the numbers behind the savings, many homeowners forget to research other factors that contribute to how solar panels save them money. At Shop Renewable Energy, we educate each prospective customer on how the type, size, and design of solar panels will all impact their lifelong solar savings. In today’s post, we will explain how to determine the energy production of a single panel and show you the best way to determine your solar savings!
What Types of Solar Panels Exist in the Residential Industry?
Although scientists are constantly improving solar technologies, there are currently three types of solar panels that dominate the entire industry: Monocrystalline, Polycrystalline, and Thin Film. Each of these panels differ in appearance, technology, efficiency, cost and warranty. Despite their many differences, each one has its unique advantages, making all of them a viable option for residential homeowners.
Thin film panels are the most unique type of solar panels. While they are the least energy efficient solar panel, their two biggest advantages are their low cost and ability to maintain panel efficiency at high temperatures. In the upcoming years, thin film panels should see some minor improvements and become a popular choice for prospective solar customers.
Polycrystalline panels have been gaining traction in the residential solar industry in recent years because of their low production cost and high efficiency. Despite these benefits, they are the largest and least attractive panels, causing many homeowners to choose monocrystalline panels.
Monocrystalline panels are the oldest and most developed panel in solar tech. Despite being the most expensive, they are the most popular panel because they are the most space efficient. This means they produce the most electricity in the smallest space, making it the perfect panel for residential homeowners.
Is Bigger Better?
Now that you have a better understanding of the types of solar panels available to homeowners, let’s figure out if size really matters when it comes to solar. It’s reasonable to think that a bigger panel means more solar cells and more power being produced, but larger solar panels haven’t really entered the residential industry. Although these big panels can be seen on large buildings or in solar farms, they’re simply not realistic for residential homeowners. They’re too big and awkward to fit on a roof or in a backyard. Thus, over the years solar manufacturers have created the optimal residential solar panel with a standard size of 65 inches by 39 inches. These panels are the perfect size because they can be configured in a variety of shapes to function on any roof and still have a high number of solar cells. In fact, each one of these standard panels has 6 rows of 10 solar cells. Each solar cell absorbs sunlight and transfers it to the home through a network of wiring and inverters. Ideally, one of these panels is rated to produce 320 watts of energy an hour, which is enough to power a fridge and freezer. Real-world settings include several variables that are not featured in lab tests, which means that solar panels never perform at 100% efficiency.
What makes solar panels less efficient?
We all wish that solar panels always performed at their peak projections, but there are 5 common variables that contribute to the efficiency level of all residential solar systems.
Sunlight:
The biggest factor for determining how much electricity a solar panel produces is the amount of sunlight it receives. One way that solar companies guarantee maximum sunlight is placing panels on southern facing roofs. Throughout the course of the day, the sun will constantly shine on the southern facing roof. If you don’t have a roof that faces south, a couple extra panels on eastern or western facing roofs can produce the same amount of power. Any shading on your roof by trees will also cause a large drop in overall efficiency. Luckily, trees can be removed, and many states have solar easement laws that allow homeowners to remove any objects on their or neighbors’ properties that block sun from their roof.
Weather:
We know that solar panels stop producing electricity at night, but what happens to them during cloudy weather? Surprisingly, they continue to produce energy, just at a slightly lower rate. Although cloudy days greatly decrease the amount of visible light, we often forget that light has a wide spectrum, meaning that along with visible light there are some forms of light our eyes don’t see. For example, ultraviolet and infrared lights are two “invisible” lights that shine through clouds and can be absorbed by solar panels. All in all, cloudy weather usually decreases panel efficiency by only 10 to 20 percent. Surprisingly enough, homeowners in states with cloudy weather often save more by going solar because electricity costs more in these states. So, don’t let those clouds deter you from choosing to go solar!
Roof Angle:
The way that the sunlight hits your panels is crucial to overall panel efficiency. The optimal pitch angle for a roof with solar is about 30 degrees. Because the sun moves throughout the day, a southern facing roof with this angle of pitch can capture the largest amount of sunlight possible. If a homeowner were to decrease the angle of their roof by 5 degrees, it would cause a 10% decrease in efficiency and would result in loss of savings. The majority of homes have a 30-degree pitch, and adjustments can be made to roofs with different angles to increase solar panel efficiency.
Temperature:
Of all the aspects that contribute to less efficient solar panels, temperature seems the most counterintuitive. You would think that a higher temperature means more sun, which means more electricity produced by your panels, but that is not the case. Once panels reach an internal temperature of 77 degrees Fahrenheit, they begin to overheat and underperform. The higher the internal temperature, the lower the solar panel’s efficiency. Luckily, this doesn’t have a huge impact on overall efficiency and many scientists are working to build panels that maintain a lower internal temperature.
Surface Maintenance:
For the most part, variables that cause a decrease in solar panel efficiency cannot be controlled by the homeowners, but many people forget that there is one thing they can do to help panels perform at higher efficiencies. By simply cleaning your panels once a year, homeowners can remove dust, dirt, and pollen that block valuable sunlight from being absorbed by your panels. For some homeowners, this might not be the simplest task, but there are options to have a company clean your panels and bring them back to peak performance!
So How Much Do My Panels Actually Produce?
As you can see, the answer to this question is different for every homeowner. It depends a lot on where you live and the conditions of your roof. After factoring in all the variables listed above, the average 320-watt panel should produce anywhere from 200-265 watts. Because this is a large range, we recommend getting a free custom-designed savings report from one of our trusted sponsors.
SRE Custom-Built Design and Proposal
At Shop Renewable Energy, we have an entire team that is dedicated to designing custom solar systems. Each member of the team is highly trained and knows the ins and outs of solar technology. Our design team uses a software that allows us to see the impact of shading from trees on your roof and where your panels will spend the most time in the sun. As a rule of thumb, our designers place as many panels on the south facing eaves because they generally spend the most amount of time in direct sunlight. If you don’t have a southern facing roof, east and west facing roofs get enough sunlight to make solar panels a viable option. By creating a simple calculation, our team of designers can determine how much electricity each panel will produce and how many panels your home will need to offset the amount of electricity that you desire. The best part of this whole process is that it is absolutely 100% free! The custom design also includes a proposal that outlines projected lifetime savings, pricing, financing options, and solar incentives.
To make the process as pain free and quick as possible, we have our customers fill out a request for a custom design in the link below, and then we set up an appointment to talk through the design and proposal. So, don’t wait to find out how much electricity the panels on your roof could produce and get started on your solar journey today!
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