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HomeExclusiveHow Many Solar Panels Can I Get On My Roof

How Many Solar Panels Can I Get On My Roof

Other Ways To Measure Your Roof

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If you have a proper safety harness, you could go up on the roof and take a direct measurement with a tape measure. Thatâs risky for personal safety, and walking with a heavy foot on your roof can damage your shingles. So I donât recommend that.

Instead, if you have a rectangular section of roof, you could take the measurement from the ground. This should be more accurate than using a tool based on satellite photos.

Take your measurements from the corners of the roof where they meet the ground: Vector art courtesy macrovector_official/

Once you have X and Y, multiply them to get the area on the ground. So, if your X = 25 feet and Y = 12 feet, your area on the ground would be 300 feet². But thatâs not the area of the roof, because it is sloping. We need to do a little trigonometry.

You need to measure the angle of the roof, and you can do that with a smartphone app like Measure for iOS or Bubble Level for Android. Measure comes pre-installed on iPhones, so you should have it already.

Of course, this isnât as accurate as going up on a ladder to take a measurement, but it sure is a lot easier, and good enough because weâre just doing this exercise to get a rough estimate of our panel count.

To take a measurement, stand underneath the roof section you want to measure, and hold up the edge of your phone so that itâs parallel with the roof. Hereâs what it looks like using Measure: Measuring your roof slope from the ground

Can Solar Panels Be Installed On A Metal Roof


Many metal roofs are lightweight, and solar panels should not be a problem for them. However, you need to make sure that when mounting solar panels on metal roofs the weight is spread out over more than one part of the roof, to prevent sagging in the middle.

A durable metal roof has the ability to last between 50-60 years, outlasting the average lifespan of a solar panel. This will ultimately eliminate multiple installation fees, as the roof will not need to be replaced along with the solar panels.

Preserve Peace Of Mind

Rooftop solar panels with battery storage generate electricity and provide a backup power solution. During an outage, Brightbox keeps preferred circuits powered. Our energy storage system enables you to run four 15-20 Amp, 120V circuit breakers for approximately 8 to 12 hoursenough to keep essentials humming until the sun rises.

Solar cant change the weather. But, having electricity during an outage gives you peace of mind and a value beyond money.

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Size Of Your Home And Available Roof Space

Larger homes tend to consume more electricity, and they generally need more solar panels. However, they also have the extra roof space necessary for larger solar panel installations. There may be exceptions to this rule for example, a 2,000-square-foot home with new Energy Star appliances may consume less power than a 1,200-square-foot home with older, less-efficient devices.

When it comes to installation, solar panels can be placed on many types of surfaces. However, your roof conditions may limit the number of solar panels your home can handle.

For example, if you have a chimney, rooftop air conditioning unit or skylight, you’ll have to place panels around these fixtures. Similarly, roof areas that are covered by shadows are not suitable for panels. Also, most top solar companies will not work on asbestos roofs due to the potential health risks for installers.

Solar Panel Roof Load Calculator: Will My Roof Support Solar Panels

How Many Solar Panels Can I Fit On My Roof?

Everyone is looking for sustainable and cheaper energy sources thanks to the ever-rising prices of fossil fuels.

A majority of people have decided to go solar to reduce their dependence on the grid power and become . Use solar on your roof is a great way to generate power completely behind the meter.

Having a roof to place the solar panels is a crucial prerequisite for the PV system installation process.

But most people wonder, will my roof support solar panels? A solar panel roof load calculator helps you to establish the size and the weight of the solar panels that your roof can accommodate.

When you want to install solar panels, it is vital to understand certain features of the roof and the solar panels.

Solar panels differ in weights and sizes depending on the manufacturer and the brand. It is essential to determine whether your rooftop can support the solar panels before you plan a installation.

In this article, we will look at some of the core factors that determine whether a roof can support the PV system.

The solar panel roof load calculator is crucial when you want to establish the size and the weight of the solar panels that your roof can support.

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Factors That Determine How Many Solar Panels You Need

You may think that the size of your house determines how many solar panels you need, but it doesnt! To really understand how many solar panels your solar energy system needs, you need to determine the following:

  • Your energy usage: The more electricity you use, the more solar panels you need to cover your electricity costs
  • Sunlight in your area: Homes in areas that receive less sunlight will need more solar panels to eliminate their electricity bills than those in sunnier states. As a rule of thumb, the southwestern United States gets the most sun in the country, while the northeast gets the least
  • Panel wattage: The wattage of the solar panels you choose, also called the power rating, determines how much energy the panels will produce and most solar panels installed today have a power rating of about 320 watts per panel fewer panels are needed when you install panels with high wattage ratings

Below, solar expert Will White breaks down everything you need to know to figure out how many solar panels you need to power your home.

What If You Need Additional Solar Power

After reviewing the different factors, the amount of solar power you can generate, given your space, may not be enough. If this happens, you can reduce your power consumption and make your home more energy-efficient by getting more energy-efficient appliances.

If you do not want to make lifestyle changes or switch your appliances to more energy-saving options, you can install ground-mounted solar panels instead of a rooftop system.

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Considering Adding A Battery

If you are planning on installing a panel and battery system, the system size equation can change. Your solar panels need to generate enough to directly power your appliances during the day and charge your battery. If you can afford a 6.6kW system and have the roof space, then you may not need to buy more solar panels to charge your battery. The size increase depends on how much battery storage you believe you need and, your solar expectations during winter months. Consider the example for a Brisbane property below:

Electricity use:

  • Daylight use = 10kWh
  • Winter electricity 20kWh

A 6.6kW solar system in Brisbane would generate, on average, nearly 28kWh per day. Enough in theory to power the households electricity day and night, in this instance, 25kWh.

The output of a 6.6kW system in Brisbane:

  • Average daily output = 27.7kWh
  • Winter daily output = 18.9kWh

The winter output of the 6.6Kw system of 18.9kWh nearly generates enough to power the total daily electricity use, which includes charging the battery then drawing on that power at night. However, if the winter electricity demand was higher and more like the daily average of 25kWh, then the household should consider a system size of 8.5kW or more.

How Much Do Solar Panels Cost On Average

Why I put Solar Panels On my Roof Lots Of Greek Numbers

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.

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Are Solar Shingles Better Than Solar Panels

The main reason why people are more interested in solar shingles than solar panels is that shingles look more aesthetically pleasing. They definitely give your roof a nicer look, but are they really better than traditional solar panels? Lets assess the situation:


  • Have a higher home value


  • Less efficient in comparison to conventional panels
  • Higher module temperatures
  • Only a few contractors offer this option

It is apparent that solar shingles have quite a few drawbacks.

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Type Of Solar Panel And Efficiency Rating

High-efficiency panels can deliver more watts per square foot, which means you need to purchase fewer of them to reach your electricity generation target. There are three main types of solar panels: monocrystalline, polycrystalline and thin-film. In general, monocrystalline panels are the most efficient solar panels, followed closely by polycrystalline panels. Thin-film panels are the least efficient.

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Factors To Consider When Determining How Many Solar Panels You Need

When determining how many solar panels you need, its important to start by thinking about what your goals are and why you want to go solar in the first place. Do you want to maximize your return on investment? Do you want to save as much money as possible? Do you want to reduce your upfront costs? Do you want to have the biggest environmental impact and reduce your carbon footprint as much as possible? Most people want a balance of these goals, and may have other priorities as well, so its helpful to get a clear idea of what your specific end goals are before you start designing a solar power system.

Once you have your goals in mind, then you can determine how many solar panels you need to get there. This calculation is going to depend on how much energy your family uses, how much roof area you have available for solar panels, the location of your home and the angle of your roof, how much sunlight shines in your part of the country, the efficiency of the solar panels youre using, and if your local utility offers net metering. Plus, you also need to consider your budget, because a large solar power system might produce more energy, but its going to cost more for the initial installation as well.

Here are a few things you should think about when determining how many solar panels you need for your roof.

How Many Watts Do You Currently Use

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Look at your electricity bill for average usage. Look for Kilowatt Hours Used or something similar, and then note the length of time represented . If your bill doesnt 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, so if your bill doesnt 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 kW.

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 900 kWh per month. So thats 30 kWh per day or 1.25 kWh per hour.

Your average daily energy usage is your target daily average to calculate your solar needs. Thats the number of kilowatt-hours you need your solar system to produce if you want to cover most if not all of your electricity needs.

Its important to note that solar panels dont operate at maximum efficiency 24 hours a day. . Weather conditions, for example, can temporarily reduce your systems 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.

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Size And Rating Of Your Solar Panels

Solar panels can vary in size and rating, leading to different sized systems for the same amount of energy output. Some panels might be smaller but have a higher watt rating, which means theyre more efficient than a larger panel with a lower rating. Thats why you must consider the efficiency of the panels when determining the total solar panel system size for your roof.

While the efficiency of solar panels might vary, solar panel sizes typically dont, as most companies have a standard solar panel square footage to make installation easier. The standard solar panel size dimensions are about 65 inches by 39 inches, which is roughly 17.5 square feet.

Why Does The Biggest System Not Have The Largest Savings

There may be days throughout the year where you consume more energy than your solar system produces, and days where you consume less. Many electric utilities add up all the excess energy that you generate during the year, and subtract it from your total energy consumption during that year. You only have to pay the difference. This is called net metering.

Some utilities will not give you full credit for generating electricity beyond what you consumed that year. Therefore, to maximize your savings, you want to base your system size on your expected electricity usage, without generating a lot of net excess over the year that you cant use.

Our recommended system size on your order is based on offsetting your current energy usage, determined by the average electric bill that you enter. If you plan to add an electric vehicle or other electric appliances in the future, you may want to consider getting a larger system size.

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Will I Have The Ability To Monitor How Much Power I Am Generating Or Using Throughout The Month

Yes. There are actually a couple of different ways you can monitor your usage. There are some basic indication lights on the hardware itself that lets you know your solar array is connected and producing electricity. You can also monitor the net-meter installed by the power company which has a few different screens. These screens indicate how much power has been sent and received by the power company.

But perhaps the best way to monitor your overall performance is with the MyEnlighten Mobile App, the monitoring platform created by Enphase Energy. With this app you will be able to see clear indicators when your system is operating normally and if there are any issues with any of your panels. You can also monitor how much energy you have produced and consumed that day. The app keeps a detailed log of your systemâs power production throughout the day in 15-minute periods, both currently and through the time of installation. At the end of the year, you will also be able to see how much power you produced, along with your most productive months.

What Size Solar Energy System Do I Need

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First off, youll need to evaluate how much energy you typically consume in a given month. Knowing this will help you calculate how big of a residential solar energy system youll need to install. Keep in mind that your energy consumption will fluctuate given the time of year and where you live. Youre going to use up a lot more energy during hot summer months and during the dead of winter when your air conditioning unit and your heater are likely running non-stop, compared to in the fall and spring when the outside temperatures are more mild and dont warrant as much electricity to run your heating and cooling units.

The average household in the United States consumes about 11,000kWh of electricity per year. And the average size of solar energy systems installed in most homes is 5kW. To break it down a little further, one kilowatt hour is equal to 1000 watts of power used in one hour. Youll need to gather data from your utility bills over the last year, and most utility companies will calculate your average automatically if you ask, to determine what your average monthly/yearly rate of energy consumption is. This will inform how many solar panels youll need to install in your home to equip your energy needs.

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How Much Solar Power Can You Generate By State

Of course, there are many assumptions that we used that differ for every solar panel system. One of the major difference-makers is geographic location, which directly impacts the hours of quality sunlight your solar panel system will get. We used 5 hours per day as our average aboveheres how that number changes geographically, while still assuming an average roof size of 1,700 square feet and 320 watt solar panels:

How much solar energy can you generate on your roof by state?


*Assumptions: 17.5 square foot/320-watt solar panels, 5 sun-hours per day

How Much Power Does Your Home Use Annually

To calculate how many panels you need. It would help if you determined how many solar panels are necessary to offset the amount of kWhs across a full year. Based on the average amount you consume daily or monthly, you can calculate how many kWhs of power your home consumes on an annual basis. A kWh is a unit of measurement for the amount of energy that the utility company uses to gauge how much electricity your home consumes. Your electricity cost is based on kWh and how much you consume.

The easiest way to determine your annual kWh consumption is by taking the average daily usage and multiplying it by 365 . This number is typically found on your electricity bills first page, near the bar chart graph.

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