How Many Solar Panels Do You Need: Panel Size And Output Factors
How many solar panels does the average house need? How many solar panels do I need for a 3-bedroom house? How many solar panels do I need for a 2000 sq. ft. home? These are all common questions for an aspiring solar homeowner. Determining how many solar panels youll need for your home requires first knowing what your goals are.
Do you want to minimize your carbon footprint? Maximize the 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:
Your average energy requirements
Your current energy use in watts
The climate and amount sunlight in your area
The efficiency of the solar panels youre considering
The physical size of the solar panels youre considering
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 to get to your target energy output. But if your usable roof area is limited, or if its 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.
Calculate The Cost Of Solar Panels
One standard solar panel produces about 1.24 kWh per day, and costs around 65 to 75 cents per watt. Solar panels from well-known manufacturers run as high as one to two dollars per watt.
Based on your results from the solar panel calculator above, you can multiply your recommended wattage by 65 or 75 cents to get a ballpark cost for all of your solar panels.
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How Do I Calculate Solar Panels For My Home
Once you have found your daily energy consumption, it can be used to size your solar panels.
It needs to be said that solar panel power ratings are not an accurate reflection of the actual power generation in real-life conditions.
In fact, there are many losses associated with a working home solar system. As much as 23% is normally lost and must be deducted from the solar array power rating see infographic below:
Infographic showing solar panel losses solar calculations must consider losses
The calculator I provide later on in the post takes these losses into account, but for this example Ill go through the process manually step-by-step.
Suitability In Remote Areas
In cases where the home or property in question is not connected to the local grid or now power is available in an area, installing off-grid solar systems is one of the best and one of the most affordable options. There are several initiatives going on in Africa to help these energy poverty areas.
Further, the installation of the off-grid system is significantly simpler than that of the traditional electrical grid. This is especially so in remote areas where homes are often located far away from electricity poles
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Planning A Home Solar Electric System
There are a number of steps to follow when planning to power your home with solar energy. After choosing which option is best for you to use solar , follow the steps afterward that apply to you. Your solar energy installer and local utility company can provide more information on the exact steps you will need to take to power your home with solar energy.
How To Size A Solar System That Really Works
Figuring out the proper size of a solar system, how many solar panels are needed, is one of the most asked questions we receive. Especially sizing an off-grid system involving a battery bank is considered black magic, even by experienced solar installers! This article will help you determine what you need to get the job done, both for grid-tie and off-grid systems.
Before we get started, a note of caution: The Internet is full of people that claim they are running their whole house off of a little 100 Watt solar panel! Unfortunately reality is usually not that good. Solar photovoltaic power works! In fact, it works very well and very reliably, though even modest energy use can take more solar panels than one would expect. This article will explain where the numbers come from so you will know exactly what it takes!
The first split-in-the-road is grid-tie vs. off-grid. For a grid-tie system there usually is net-metering available, which means that during the sunny summer months we can overproduce and store the excess on the grid as a credit, for later use in winter when the solar system falls short. An off-grid system cannot do that of course, it uses batteries to store excess to get us through the night, and it needs to be sized a little different. We will start with a look at grid-tie solar systems.
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Select An Appropriate Solar Charge Controller
Solar charge controllers have two primary functions within an off-grid solar power system. Firstly, it facilitates and optimizes the process of charging the deep cycle batteries using the energy generated by the solar panel. Secondly, they prevent electricity from flowing out the batteries and through the solar panels when there is no sun.
Solar charge controllers, therefore, protect the battered bank by ensuring it does not get overcharged. Subsequently, this enhances the longevity of the batteries.
One must ensure that the solar charge controller chosen can take in the voltage of the solar panel array and output this power to the battery banks energy reserves. It is also equally as important to ensure that the solar charge controller has the required capacity to handle the current from the solar panel array.
To get an estimate of how many amps a controller needs, one needs only to divide the wattage of the solar panel arrays by the voltage of the battery bank. Alternatively, one may opt to many the short-circuit current of the solar panel array by 1.56.
According to experts, using MPPT controllers can result in between 15 and 30% more power produced from the solar array as compared to a PWM solar controller. However, MPPT controllers are also more expensive than PWM solar charge controllers.
Get Free And Instant Quotes From Installers In Your Area
We hope the above points are helpful to you. Take 30 seconds to complete our Solar Quote Comparison Request form, or feel free to give your Solar Choice broker a call on 1300 78 72 73 to further discuss what size installation best suits your budget and energy needs. Our service is 100% free to our residential customers.
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Choose The Right Solar Panels
If you have a small or odd-shaped roof, solar panel size is an important consideration when deciding on the size of a solar system. Take these factors into account:
- With a large usable roof area, you can buy more larger panels to get to your target energy output.
- If your usable roof area is limited or partially shaded, using fewer smaller high efficiency panels will ultimately be the most cost-effective, long-term solution. You can add more panels later on to accommodate increased energy needs.
Solar System Sizing Table
If youre considering solar panels for your home, youll get the most value from them by directly self-consuming the energy that they produce during the daylight hours. The simple reason for this is that using the solar yourself allows you to avoid purchasing expensive energy from the grid instead of earning only a small credit for sending it into the grid. This is a crucial fact about going solar in Australia today.
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How Do Solar Panels Work
Simply put, solar panels absorb photons that then tap electrons free. Once theyre free from the atoms, it creates electricity! Solar panels take in light and directly turns it into a flow of electricity to use.
- Solar panel cells absorb sunlight
- They convert the light into DC power.
- All systems need some type of inverter to convert that power to AC power.
- The electricity is then sent through wires into your home
- That powers everything connected to it
- Any excess of electricity produced is then fed into the electric grid
Solar systems are not complicated and easy to understand once you have the basics down. Now that you understand how they work, lets take a look at how long they last
How Much You Want To Spend
Another big factor – one that probably influences your backup-energy goals – is how much you want to spend on batteries for your solar system. Unless you pay high demand charges, solar storage battery banks probably wont save you any money .
You may be able to use the 26% Federal Solar Tax Incentive. But in 2021, this scales back to 22% and drops to 10% for commercial systems only. Another incentive that may be available to businesses and commercial solar system owners is accelerated depreciation.
If your system is in Maryland, theres an extra incentive you could take advantage of: the . This incentive offers 30% off the cost of an energy storage system installed during 2019 but is capped at $5,000 for homes and $75,000 for businesses.
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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 cant 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 subscribers 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 subscribers annual electricity costs as possible.
Final Thoughts On How Much Solar Power Do I Need For My House
The best advice is to reach out to an experienced solar panel installer. The average installer team does one or two home installations a day. Therefore, they will be able to see all the factors that would impact your specific site.
And now you know pretty much everything you need to know about solar power production and how much solar energy it takes to power your home. We hope you found this as enjoyable to read as we found it to write. Now go out, and enjoy the sunshine!
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How To Determine How Many Solar Panels You Will Need
Taking into account the factors in the section above, a simple formula to use to estimate the size of the system that you need is kWh per year / 1200 = the size system you need . Our actual system design will take many other factors into account, but this should be a good estimate. Once we have the kW needed, we will select the number of panels by reviewing your available roof space and your target budget. For example, if space is an issue, we will need to select a higher efficiency panel to keep the footprint small and the production high. Likewise, a cheaper panel could be selected if there is more available space to work with.
You can do the math or better yet, use the examples we compiled for you to get a ballpark idea of the number of panels youll need. We suggest contacting a solar installation professional to determine the exact size for a system that best fits your needs. In the meantime, this chart is a good reference point.
Note: A 330W solar panel covers roughly 19.5 sq. ft.
Most homeowners will need a 5 kW to 20 kW solar system. This would obviously vary depending on a few factors, such as: if you have a heated pool or use electric heat.
A $120 average monthly electric bill will need a 10 kW solar system to cover their annual energy usage. A 10 kW solar system will utilize 32 330W solar panels and cover roughly 624 sq. ft.
Few Things About Solar Panel Output Efficiency
Solar panel type and quality make a significant difference in terms of solar output and efficiency. Not all solar panels are the same.
For instance, monocrystalline photovoltaic solar panels are known to be the most efficient solar panels on the market, but also the most expensive.
Their two main advantages over the other types of solar panels such as polycrystalline or thin film panels is that 1) they absorb more sunlight than conventional cells and their output efficiency is not affected that much by temperature and 2) they occupy less space. These are an ideal option if you do not have enough roof space for standard panels.
On the other hand, polycrystalline panels are cheaper, they are less efficient and therefore occupy more space, but offer a better return on investment than monocrystalline panels.
Because of these wide differences in quality and efficiency, its up to you to decide which solar panels are right for your home.
The main takeaway is that, the more efficient the panels are, the more power they can produce, and the fewer photovoltaic panels you will need on your roof to get the same energy output as you would get with polycrystalline or thin film solar panels.
Overall, if money is not an issue, monocrystalline panels are the best option.
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Calculate A Solar Energy System Requirement
You need to match the kilowatt hours of your solar PV system to the kilowatt hours that your appliances will use. To approximately estimate the energy requirement for a period of time, we need to multiply the hourly power consumption by the number of hours of intended use. An example for the same would be a 40W appliance in domestic use that will be used for 2 hours per day. The daily energy consumption for it would be 40*2 = 80 Wh.
Repeat that exercise for every appliance individually to calculate the daily energy requirement for your solar energy system. Add in any appliance that will use power while connected to the solar panel. The result will give you an indicative total energy requirement for the solar panel to produce for the day. You can work out the number of panels needed a few ways.
You calculate how many solar panels you may need by dividing the maximum hourly solar energy system output by the wattage output of one single panel. The number of solar panels of the size used in the calculation will theoretically meet that energy demand during a sunny day.
Another way is to multiply the households hourly energy requirement by the peak sunlight hours for the area. Then divide that answer by the wattage of the solar panel intended to be used.
How Much Does A Solar Panel Cost
Prices have been coming down steadily over the years. The total cost will depend on how many kilowatts of power your array will generate. According to consumer reports, after solar tax credits are accounted for, the cost for a solar panel system on an average-sized house in the U.S. in 2021 ranges from $11,000 to $15,000.
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Solar Panels For A 1500 Square Foot House
The average home in the United States is roughly 1500 square feet. With a home of this size, the typical electric bill comes in around $100 month. In order to cover the electricity for this home, you would need an estimated 15-18 solar panels.
For example, a typical fridge may be rated for 250 watts and runs for 4 hours a day. 250 watts X 4 = 1000W. A 1k watt is equal to 1 kWh of energy in a day.
This, of course, is a general estimate and eclectic usage, sunlight hours, location, and the type of panels can change this amount.
How Much Does The Shape Of My Roof Matter
In short, a lot! Solar panels on average are about 3×5 feet in size and depending on how much energy you need them to produce, you might need 20 panels, thats 300 square feet of solar panels that need to fit on your roof. Along with the space you need, you also need to look at what direction your roof is oriented. A true southern-facing roof plane is the ideal spot to install panels in North America. If your roof only has space for panels on a plane that is facing a different direction, solar can still be a good option, you just may need to add additional panels to make up for lost hours of solar production. An expert solar installer will assess your roof to optimize the placement of panels.
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