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How Many Solar Panels Do I Need. Sunpower panel size

How Many Solar Panels Do I Need. Sunpower panel size

    What is cost for Sunpower Solar

    A simple and fast way to compare solar installers is based on their cost per watt. To calculate the cost per watt, take the total price and divide it by the DC watt size rating of the of the system.

    Sunpower has installed thousands of PV systems. The average solar panel system from Sunpower is 7,870 watts (7.9 kW) and costs 36,300 for a price per watt of 4.60. The expected cost per kilowatt hour (kWh) is 0.17.

    Most of the systems sold by Sunpower use their lease or power purchase agreement (PPA). For these financed PV systems, the lifetime price per watt is 5.60.

    Sunpower are 11% above the industry average for a cash purchase, and a whopping 70% higher when leased. Sunpower charges about double the price you would pay for a comparable solar panel system from SunWatts. That means the average customer could save 18,500 by working with us.

    Compare Sunpower To Other Solar Companies

    Our are lower than Sunpower, SunRun, REC, Vivint and the rest. A SunWatts system, including design, permits, parts and labor, costs 40% less than the average installation. You can also Do-It-Yourself for even bigger savings. This fact is based on actual costs PV solar projects reported by CSI Solar Statistics. Review the following infographic to see how we compare to other top solar companies.


    The Lowest Cost For The Best Solar Panels

    It is not magic. Our for solar are simply 40% less than the average competitor. Here is a how we do it.

    • We design a system to meet your power goals and set your budget.
    • Our bigger brand selection gives you choice and buying power.
    • We shop the market. You can DIY or we will have solar installers compete for your business.

    No matter how you decide to go, you get name brand manufacturer warranties and all the tax credits and rebates. The system will be UL certified to pass any permit or utility inspections. You will enjoy 25 years or more of renewable solar energy. You will also spend about 40% less than the average solar company charges. That means more green in your wallet.

    Now some may claim to offer free solar installation. Wrong! There is nothing free about it. They are really offering financing or leasing, where you have to sign a long-term 20 year contract. In fact, those no money up-front solar lease or PPA programs cost 6.50 per watt. You end up spending more than double the price (227%) than you should for so-called free installation.

    Compare Of Top Solar Companies

    There were more than 40,000 solar energy systems installed in California in 2013. 2016. The average PV system installed is 6,600 watts (6.6 kW) and costs 29,700 for a cost per watt of 4.50. The expected lifetime cost per kilowatt hour (kWh) is 0.17.

    In comparison, the average 6,600 watt PV system from SunWatts costs 17,800 for a cost per watt of 2.70. The expected lifetime cost per kilowatt hour (kWh) is 0.09. Our solar systems qualify for renewable energy tax credits and rebates. So you can reduce the sticker price by 30% or more for an even lower net cost after government incentives.

    Want to know how much do installers charge for their solar panel systems? Follow these links to review the pricing details about top solar companies based on their actual real-world projects.

    How Many Solar Panels Do I Need?

    As more homes throughout the country consider installing solar panels, one question commonly asked is, “how many solar panels do I need?”. Well, it depends – there are a few factors that go into determining how many solar panels you would need to power your home or business; home energy usage, roof or property surface area, orientation of your roof and geographic location. In this piece, we’ll break it down for you.

    How much solar energy do I need?

    When determining how much solar energy you need; your home’s average energy usage is the first thing to look at. According to the U.S. Energy Information Administration, in 2019, the average electricity consumption for a U.S. residential utility customer was 10,649 kWh. That’s an average of about 877 kWh per month. To understand your own usage, a good rule of thumb is to look back at your total energy consumption from the last twelve months on your utility bills. Most utility bills provide this information. Divide that number by 12 and you have a great estimate of what you’ll need your solar panels to generate each month.

    Where you live also plays an important role in how many solar panels you’ll need. For example, states in the northeast endure longer winters accompanied by shorter days during cooler months. Residents in these regions will most likely need more solar panels to generate the same amount of power as residents from sunnier and warmer climates would. It’s important to understand how many peak hours of sunlight your geographic location receives on average.

    Factors That Affect Solar Panel Output Efficiency

    All things being equal, the design of the solar panel determines how efficient it is. This, in turn, specifies how well each square foot can convert sunlight into energy.

    For example, gridlines on most panels reduce the active surface area. Therefore, they are not as efficient as those without them. In addition, grid panels are susceptible to peeling, further reducing efficiency.

    Quality plays a role, too. For example, if the construction is subpar and introduces corrosion and cracking, it can also impact the ability of the panel to absorb sunlight.

    But as a rule of thumb, expect residential solar panels to give you between 150 – 370 watts. This translates to an average solar panel’s wattage per square foot of 15 watts.

    How Much Do Solar Panels Cost on Average?

    The average cost of a solar panel is around 0.65 to more than 2 per watt for high-end models. That means an average 6 kW system will set you back up to 12,000, depending on the location. This is exclusive of installation costs, which can bump the price up by another 5,000 – 10,000.

    As a rule of thumb, PV systems in warmer locations are cheaper but require more panels, while the opposite is true with colder climates.

    Fortunately, tax credits and incentives can cut solar panel installation costs and provide further savings throughout their lifespan.

    How Many Solar Panels to Power a House?

    When estimating how many kilowatts of solar do I need, it’s important to consider the size of your home. A home size of 1500 sqft would consume an avg. of 633 kWh/month, on the other hand, a 3000 sqft home would consume an avg. of 1185 kWh/month. An average homeowner would need about 28 to 34 solar panels to fully offset their electricity usage. The chart below is an estimate of the number of panels you could potentially need based on the size of your home.

    How many solar panels do I need for a specifically sized solar system?

    To determine the number of panels you need to achieve a given solar system size, divide it by the wattage of each panel (which averages around 320 watts).

    For example, if you’re aiming for a 4 kW system, you’ll divide 4 kW (or 4,000 watts) by 320 watts to get 12.5. Round up the answer to 13, which is the number of panels you need.

    How many solar panels do I need for common appliances?

    You can also determine the number of panels you need on a per appliance basis. This approach is helpful if you want to add panels because of increased usage or when buying a new appliance.

    To calculate this, divide the average annual wattage of the appliance by the panel wattage. For example, a 600 kWh refrigerator would need two solar panels (600 / 320)

    Summary: Step-by-Step Guide to Determining Solar Panel Needs

    Here are the steps to figure out the question, “what size solar system do I need?”

    Measure your annual kWh usage or the yearly electricity consumption of your house. You can either consult a year’s worth of monthly electric bills or use the average American house consumption figure of 10,649 kWh / year as an estimate.

    Figure out your panel wattage, which is how much electricity your panel produces under ideal conditions. For simplicity’s sake, you can use 320 watts as an estimate.

    Estimate your production ratio, or how much electricity your panel produces based on the average sunlight. You can compute this by dividing your system wattage by its electricity output in a year. Or you can use the US estimate of between 1.3 and 1.6.

    Plug the data into the formula: Panel number = kWh usage / production ratio / wattage

    For example, let’s say your house has an estimated 12,800 kWh consumption. Assuming a production ratio of 1.6 and 320-watt panels, you would need:

    Some homeowners might also ask, “how many square feet of solar panels do I need?” To answer this question, you first need to know that an average residential solar panel is around 17.5 feet. Then multiply this figure by the number of panels you need based on the steps we just outlined.

    Thus, in our above example, a 12,800 kWh consumption will need 437.5 square feet of solar panels (or 25 panels x 17.5 feet)

    Example Calculations

    Before we get into the examples, it’s helpful to note that a home’s power usage isn’t entirely dependent on its square footage. Instead, the number of residents and their energy habits play a much bigger role.

    But for the sake of people asking, “how much solar power do I need?” in terms of square footage, we’ve illustrated the examples in these terms.

    many, solar, panels, need, sunpower

    Example 1: how many solar panels do I need for a 1000 Sq Ft Home?

    Let’s assume the consumption of a 1,000 sq ft home with four residents and average usage to be 690 kWh per month or 8,280 kWh per year.

    With a panel wattage of 320 and a production ratio of 1.4, the number of solar panels you’ll need is:

    Solar Panels = 8,280 / 1.4 / 320 = 18.48

    Example 2: how many solar panels for 2500 Sq Ft Home?

    Let’s assume that our 2,500 sq ft home houses five people with regular energy usage habits. The estimated consumption would then be 1,131 kWh per month or 13,572 kWh per year.

    Again, considering a 320W panel and a 1.4 production ratio, plugging the numbers in the equation gives us:

    Solar Panels = 13,572 / 1.4 / 320 = 30.29


    Solar Panels kWh Calculator

    You can use the calculator below to quickly determine your solar panel needs based on your average monthly kWh usage and the nearest city from your house. The latter helps better gauge the amount of sunlight you receive based on your location.

    Solar Panel Square Footage Calculator

    Alternatively, you can also figure out the number of solar panels you need based on the square footage. This is useful if you plan to install solar panels on a new house and haven’t tracked your monthly electricity consumption yet.

    However, no calculator will do this for you directly since there’s no correlation between square footage and consumption.

    But there’s a workaround. You can use the calculator below to get the predicted monthly kWh usage based on the number of people living in the house and their energy consumption habits:

    Once you get the estimated monthly kWh usage, simply plug it into the solar panel kWh calculator above.

    Not all roofs are suitable for solar panels

    Apart from estimating how many solar panels you need, you should also consider the weight of the panels themselves.

    On average, a single panel weighs around 40 pounds, adding around 2.8 pounds per square foot for a typical pitched roof and 5 pounds for flat roofs. Therefore, you need to make sure that your roof can support this added weight. You also need to consider the material, age, and structure of your roof.

    According to the National Renewable Energy Laboratory of the U.S. Department of Energy, approximately 50% of homes can’t support rooftop solar panels. Community solar programs are a common way for many homeowners, businesses and renters to go solar without actually installing anything on their roof. Participants can subscribe to a nearby solar farm and pay a lower price for the electricity sourced from it. Through Community Solar with Nexamp, the process is similar to determine the size of a subscribers’ share of a solar farm is similar to determining the number of rooftop solar panels. We simply analyze a subscriber’s last 12-13 months of energy usage and recommend a suitable allocation of our farm for them to subscribe to at a discounted rate. The end goal is to offset as much of a subscriber’s annual electricity costs as possible.

    At the end of the day, the number of solar panels you’ll need to see potential savings is unique to your home’s energy usage. Interesting in seeing how much you could save by joining our community solar program? Reach out to us by visiting our community solar page or call us at (800)-945-5124.

    LG vs Sunpower Solar Panels: Everything You Need to Know

    LG and Sunpower are the USA’s market-leading solar panel manufacturers. They both make an extensive range of home solar panels using the latest technology to help homeowners generate home solar electricity and cut down on their mains electricity costs.

    But which of these companies is the best? Does LG or Sunpower make the best solar panels? You’ll know the answer once you’ve read through this guide to the two companies and their products. And then you’ll have all the information you need to make your choice between LG versus Sunpower solar panels.

    Who is LG?

    LG Electronics is a multinational electronics company that originated in South Korea in 1958. The company began as Goldstar and specialized in the production of consumer electronics and home appliances. They specialize in products like TVs, radios, washing machines, refrigerators.

    These days LG is one of the top world corporations, employing more than 84,000 people worldwide. The company continues to specialize in consumer electronics. Still, it has branched out into technologies such as solar panels, where their technological advances are driven by the might of their enormous research development capabilities.

    Who is Sunpower?

    In many ways, LG and Sunpower couldn’t be more different. Where LG is an enormous international electronics conglomerate. Sunpower is a homegrown company specializing in solar power.

    Sunpower was founded in the 1970s by Dr. Richard Swanson, a professor of electrical engineering at Stanford University. As a leading solar energy scientist, he received grants from the Electric Power Research Institute and the US Department of energy to further his research. In 1997, SunPower’s groundbreaking technology was used to power NASA’s Pathfinder rover.

    Sunpower continued at the leading edge of solar cell technology and in 2008 produced a silicon solar cell with a world record efficiency of 23.4%. With these improvements in efficiency, Sunpower became a major manufacturer of home solar technology, making their billionth solar cell in 2014.

    These days Sunpower is a NASDAQ listed company producing powerful and highly efficient solar panels for the world market.

    Which of these companies is most successful?

    The reason for these potted biographies of LG and Sunpower is to establish their place in the market and assess whether you can expect them to be around in the future. Why?

    Both these manufacturers sell solar panels with twenty-five-year warranties. But a warranty is only as reliable as the company that offers it. If either company goes out of business, then that effectively nullifies your warranty. You need to be sure you’re buying from a lasting business.

    It seems that Sunpower is going from strength to strength, and they aren’t going to stop selling solar panels any time soon since it’s their primary business. Equally, a company the size of LG doesn’t disappear overnight. What they might do, though, is stop producing solar panels one day, just as they are planning to do with their mobile phone operation.

    Given that home solar is a relatively new industry with enormous potential for expansion, I think that you can be very confident that both of these companies are here for the long term. If I had to pick one over the other in terms of long-term prospects, I would choose Sunpower simply because they specialize in solar technology.

    How do you know if a solar panel is any good?

    I’ll quickly take you through some of the measures we use to work out the efficiency and energy production of solar panels.


    all solar panels are tested under laboratory conditions and given a wattage that rates their energy production under ideal conditions. If you buy a 350-Watt panel, that doesn’t mean it will produce that much power all the time, but different power ratings are an excellent way to compare solar panels.


    Much is made of solar panel efficiency, and it’s important. Efficiency is a measure of what percentage of the sun’s light a particular solar panel can convert into electricity. efficient panels can produce more electricity per unit area than less efficient ones.

    But, importantly, less efficient solar panels can still produce a high wattage if they are large enough. If you have plenty of space for your home solar panel installation, then don’t fall into the trap of valuing expensive, highly efficient panels over larger, cheaper panels that produce the same amount of electricity.

    Twenty-five-year output

    when you check the warranty of your solar panels, you will see that it guarantees a performance level after twenty-five years. This performance is measured as a percentage of its as-new power output. This number is an excellent measure of solar panel quality since it is effectively the manufacturer’s best guess of their product’s durability.

    The higher the warrantied twenty-five-year percentage, the better the product.

    Temperature coefficient

    the temperature coefficient of a solar panel tells you how much heat impairs its performance. Solar panels are designed to operate optimally at temperatures up to 25°C or 77°F. The temperature coefficient tells you by what percentage performance reduces for every degree centigrade above this temperature.

    Measurement Example What it means
    Size 1558mm x 1048mm x 46 mm Panel height, length and depth
    Watts Per Square Meter 200 The panel produces 200 W of energy per square meter
    Wattage 350W The panel can produce 350 Watts of power
    Efficiency 21% The panel can convert 21% of solar light energy into electricity
    Twenty-five-year output 91% After twenty-five years, the panel is guaranteed to produce 91% of its starting power
    Temperature coefficient -0.4%/°C The panel’s performance goes down by 0.4% for every degree Celsius above twenty-five

    What products do these companies sell?

    LG offers a range of domestic solar panels, including the NeON series and the NeON R series, in a few variations. The NeON is a powerful panel producing 355-375 W from sixty solar cells at an impressive efficiency of 21.7%

    The Neon 2 is a more affordable solar panel with a lower but still impressive efficiency of 19.8%, producing 350-365W in their sixty-panel models.

    Sunpower’s X series is their flagship solar panel, with high efficiency and top-of-the-range specifications. We’ll compare this with LG’s premium Neon panel.

    many, solar, panels, need, sunpower

    Like LG, Sunpower produces a more affordable panel, branded the E series. I’ll compare this product with LG’s Neon 2.

    Both companies produce several other products, but these are their most representative products and so the best to compare.

    Comparing top of the range LG and Sunpower solar panels

    Both company’s top-of-the-range panels have very similar specifications.

    Even though the Sunpower is marginally more efficient, the LG delivers the most watts per square meter, but the difference is negligible.

    Sunpower has a marginally better temperature coefficient, and the X series offers better performance after twenty-five years, but again not by much.

    So the two panels are extremely close in all regards, but in terms of overall performance, the Sunpower X-Series is the very marginal winner.

    Comparing cheaper LG Sunpower solar panels

    when it comes to their more affordable products, the differences between the LG Neon and the Sunpower E-series are a little more marked.

    The temperature coefficients are around the same, and Sunpower has a slightly better twenty-five-year output. However, this doesn’t guarantee the panel will work better after twenty-five years, just that Sunpower thinks that it will.

    But this time, the LG is ahead of Sunpower in the most critical categories. The LG Neon 2 is quite a bit more efficient than the Sunpower, allowing the panel to produce 5% more energy per square meter than its rival. This is a big difference and gives LG’s Neon 2 solar panel the edge over Sunpower.

    Sunpower E-Series LG Neon 2 Best
    Power output 327W 365W N/A
    Size 1558mm x 1046mm x 46mm 1,700mm x 1,016mm x 40mm N/A
    Watts per square meter 200 211 LG
    Efficiency 20.4% 21.1% LG
    Warrantied 25-year output 92% 90.1% Sunpower
    Temperature coefficient -0.35%/ °C -0.34%/ °C LG
    Size 1558mm x 1046mm x 46mm 1,700mm x 1,016mm x 40mm N/A

    What about the price?

    You will notice that I haven’t got to price yet, and “how much?” is often the first question you ask when you’re buying something, isn’t it?

    vary depending on where and when you buy your solar panels, but it’s reasonably safe to say that LG’s solar panels are cheaper than Sunpower’s. If you want the best performance for your buck, then LG’s solar panels are better than Sunpower.

    So which panels should I choose?

    If money is no object and you want the best performing top-of-the-range solar panel, then Sunpower’s X-series is just marginally better than LG’s Neon. Depending on the in your region, if the NeON is cheaper than the X-series, it may represent better value for money.

    When it comes to the battle of the mid-range solar panels, the outcome is much clearer, LG’s neon 2 performs better than Sunpower’s E-Series, and it’s cheaper, so LG comes out on top.

    If you have any questions or Комментарии и мнения владельцев on this article on LG versus Sunpower solar panels, please share them with us below.

    Sunpower panel size

    Determining how many solar panels you’ll need for your home means first knowing what your goals are. Do you want to minimize your carbon footprint? Maximize your return on your investment? Save as much money as possible? Most people want to save money while minimizing their environmental impact.

    To calculate how many solar panels you need, you need to know the following: how much energy your household uses; your roof’s usable surface area; the climate and peak sunlight in your area; the wattage and relative efficiency of the photovoltaic (PV) panels you’re considering; and whether net metering is available.

    One simple way of answering the “How many solar panels do I need” question is to consult a professional installer, who can give you a free home solar evaluation.

    How much solar power will you need?

    To determine your home’s average energy requirements look at past utility bills. You can calculate how many solar panels you need by multiplying your household’s hourly energy requirement by the peak sunlight hours for your area and dividing that by a panel’s wattage. Use a low-wattage (150W) and high-wattage (370W) example to establish a range (ex: 17-42 panels to generate 11,000 kWh/year). Note that how much sunlight your roof gets and factors such as roof size and battery storage will figure in as well.

    If you work with SunPower, our solar experts will handle all these calculations for you. But to give you some idea of how many solar panels are needed for the average home (or for your home in particular), here is a sample set of questions that a solar professional might use to figure it out:

    How many watts do you currently use?

    Look at your electricity bill for average usage. Look for “Kilowatt Hours (or kWh) Used” or something similar, and then note the time period represented (usually 30 days). If your bill doesn’t show kilowatt hours used, look for beginning and ending meter readings and subtract the previous reading from the most recent one.

    You want daily and hourly usage for our calculations, though, so if your bill doesn’t show a daily average, just divide the monthly or annual average by 30 or 365 days, respectively, and then divide again by 24 to determine your hourly average electricity usage. Your answer will be in kilowatt-hours (kWh). (And just in case you are wondering, a kilowatt-hour is how much power you are using at any given time multiplied by the total time the power is being used.)

    A small home in a temperate climate might use something like 200 kwh per month, and a larger home in the south where air conditioners account for the largest portion of home energy usage might use 2,000 kWh or more. The average U.S. home uses about 900kWh per month. So that’s 30 kWh per day or 1.25 kWh per hour.

    many, solar, panels, need, sunpower

    Your average daily energy usage is your target daily average for to calculate your solar needs. That’s the number of kilowatt-hours you need your solar system to produce if you want to cover 100 percent of your energy needs.

    It’s important to note that solar panels don’t operate at maximum efficiency at all times. (See Solar 101: How Does Solar Energy Work?). Weather conditions, for example, can temporarily reduce your system’s efficiency. Therefore, experts recommend adding a 25 percent “cushion” to your target daily average to ensure you can generate all the clean energy you need.

    How many hours of sunlight can you expect in your area?

    The peak sunlight hours for your particular location will have a direct impact on the energy you can expect your home solar system to produce. For example, if you live in Phoenix you can expect to have a greater number of peak sunlight hours than if you lived in Seattle. That doesn’t mean a Seattle homeowner can’t go solar; it just means the homeowner would need more panels.

    The Renewable Resource Data Center provides sunlight information by state and for major cities.

    Now multiply your hourly usage (see question No. 1) by 1,000 to convert your hourly power generation need to watts. Divide your average hourly wattage requirement by the number of daily peak sunlight hours for your area. This gives you the amount of energy your panels need to produce every hour. So the average U.S. home (900 kWh/month) in an area that gets five peak sunlight hours per day would need 6,250 watts.

    What affects solar panel output efficiency?

    Here’s where solar panel quality makes a difference. Not all solar panels are alike. Photovoltaic (PV) solar panels (most commonly used in residential installations) come in wattages ranging from about 150 watts to 370 watts per panel, depending on the panel size and efficiency (how well a panel is able to convert sunlight into energy), and on the cell technology.

    For example, solar cells with no grid lines on the front (like SunPower ® Maxeon cells) absorb more sunlight than conventional cells and do not suffer from issues such as delamination (peeling). The construction of our cells make them stronger and more resistant to cracking or corrosion. And a microinverter on each panel can optimize power conversion at the source, in contrast to one large inverter mounted on the side of the house.

    Because of these wide variations in quality and efficiency, it’s difficult to make generalizations about which solar panels are right for you or how many you’ll need for your home. The main takeaway is that, the more efficient the panels are, the more wattage they can produce, and the fewer you will need on your roof to get the same energy output. Conventional solar panels usually produce about 250 watts per panel, with varying levels of efficiency. In contrast, SunPower panels are known to be the most efficient solar panels on the market.

    To figure out how many solar panels you need, divide your home’s hourly wattage requirement (see question No. 3) by the solar panels’ wattage to calculate the total number of panels you need.

    So that average U.S. home in Dallas, Texas, would need about 25 conventional (250W) solar panels or 17 SunPower (370W) panels.

    What is the effect of solar panel size?

    If you have a small or unusually shaped roof, solar panel size and numbers are important considerations. With a large usable roof area, perhaps you can sacrifice some efficiency and buy more larger panels (at a lower cost per panel) to get to your target energy output. But if your usable roof area is limited, or if it’s partially shaded, being able to use fewer smaller high efficiency panels may be the best way to make the most possible power over the long term, ultimately saving you more money.

    Typical residential solar panel dimensions today are about 65 inches by 39 inches, or 5.4 feet by 3.25 feet, with some variation among manufacturers. SunPower panels are 61.3 inches by 41.2 inches.

    These dimensions have remained more or less unchanged for decades, but the efficiency and output from that same footprint have changed dramatically for the better. In addition, SunPower designs entire systems to have virtually no gaps between panels and uses invisible framing and mounting hardware to keep the rooftop footprint as tight, efficient and attractive as possible.

    Knowing the answers to the above questions will give you an idea of the ideal number of panels for your electricity generation needs — or at least a realistic range. Next, a professional installer needs to assess your roof architecture, angle to the sun and other factors to see if and how you’d be able to physically arrange the right number of panels on your roof to achieve your daily energy production goals.

    You should also consider net metering as you’re considering figuring out your ROI for your solar system. Net metering is how your utility company credits you for producing excess solar energy when the sun is shining and then lets you draw from those credits when you’re using conventional power grid at night, if you don’t have a solar battery storage system.

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