How To Find Out How Many Solar Panels I Need

Frequently Asked Questions Related To How Many Solar Panels Power A House

Do you still have an electricity bill with solar panels?

Once you install solar panels, youll still receive a monthly electricity bill. However, it should be lower/close to zero, or even negative! If youre still experiencing high utility bills after installing solar panels, you may need to reconsider the size of your system. Especially if you have added electricity loads since your solar installation , your current system size just might not cut it anymore.

Are there disadvantages to powering a home with solar panels?

The two main disadvantages of solar energy are the high upfront costs and intermittency, meaning that solar energy isnt available 24/7 due to the simple fact that the sun doesnt shine at night. Luckily, that problem can be partially sorted with solar energy storage. Check out our article about the advantages and disadvantages of renewable energy to learn more.

Are solar panels worth it?

Depending on your electricity prices, your energy needs, your desire to be eco-friendly, and your homes geographic location, solar panels are definitely worth installing. While the initial investment in solar panels is high, they do pay off over time by cutting down on your electricity bill. On average, EnergySage solar shoppers break even on their solar investment in about eight years.

Putting It All Together

With those variables in mind, we can roughly estimate the number of solar panels for home that you’ll need. In this example, we’ll use the average annual energy consumption, solar panel wattage and hours of sunlight that we mentioned earlier.

Let’s say that your property receives four hours of sunshine each day, and you’re purchasing 325-watt solar panels. In that case, each panel can generate 1,300 watt-hours per day . Assuming that your energy usage is in line with the average of 29 kWh per day, you’d need 23 325-watt panels to create enough electricity for your home.

Determine The Generation Capacity Of Your Potential Solar Panels

Different solar panels have different power generation capacities. Some companies sell them at 320 watts, others at 280 watts, and others still at 250 watts. Some high efficiency panel designs can even produce up to 400 watts or more per panel. We shall use 280 watts for this example.

Simply divide the total watts above by the total wattage output of your solar panel to determine how many solar panels you will need:

5,400 / 280 = 19.3 solar panels needed to cover total electricity usage

In this example, the homeowner would need a solar power system with around 20 solar panels to provide all of their energy needs over the course of a year. Solar installers typically factor in many more variables when sizing a solar power system, but this number serves as a good baseline when thinking about your own solar power plans.

When you work with Palmetto to design your perfect solar power system, we take care of the entire process, including the calculations required to find out how many solar panels you need, so you won’t have to worry about the details.

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Compare Solar Energy Plans

These are some energy deals on offer for customers with solar panels. These types of electricity plans are specifically for solar customers, and usually feature a higher feed-in tariff than standard power plans. Be sure to check all rates, fees and charges before signing up a deal.

• SA

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Ausgrid network in Sydney but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 3900kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Citipower network in Melbourne but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4000kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners. Our database may not cover all deals in your area, and please check retailer websites for up to date information.

Calculate Your Solar System Size Here Is The Math

Now that you know your goals and annual electricity company, you have all of the ingredients to determine your ideal system size. Here is the formula to use:

kWh per month /  = kW solar system size

For example, if you use 1,000 kWh per month and have an average of 6 hours of sunlight per day. That would be 1,000 divided by 6 hours * 30. Which would provide a 5 kW system sized.

A 5 kW solar energy system size means that it produces 5 kWh for every hour of direct sunlight. So this means that for your solar energy system to produce 1,000 kWh per month, you need 6 hours of direct sunlight per day and a 5 kWh solar energy system size.

If you were only to get 3 hours of direct sunlight exposure, you would require a 10 kW sized solar energy system. Therefore, the amount of sunlight that your home is exposed to significantly impacts how large of a system you require. If your kWh per month on average is less than this number, then you know your solar energy system will cover all your energy needs.

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What Is The Best Solar Panel Size

The best solar panel size is a system that suits your energy needs. As the price of solar continues to fall, it may be worth looking into a bigger PV system with higher panel efficiency. Ultimately, the best size panels for your property will depend on whats most important to you a cheaper brand with lower upfront installation costs or investing in panels with greater output capacity?

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• List of solar battery companies in Australia

The Number Of Cells And Solar Panel Size

As you might already know, the cells are the core of a solar panel.

The number of cells determines the output voltage of the panel, but it will also determine the solar panel size.

The more cells in the panel, the bigger the panel and the higher possible output voltage.

From this principle, intuitively you might sense that the 72-cell panel of the figure above, apart from being bigger, will have a higher voltage than the 60-cell one.

So, the more cells are connected in the panel, the higher the output voltage. But, for the voltage to add up the cell must be connected in series.

This is graphically explained in the figure below.

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What Affects Solar Panel Efficiency

The efficiency of a solar panel is affected by a number of factors, but two of the most prominent are the type of panel it is and how much sunlight it receives.

• Type of panel: As mentioned, there are three types of solar panels: monocrystalline, polycrystalline and thin-film. Because of the way they’re manufactured, monocrystalline panels are the most efficient.
• Amount of sunlight: If your home is heavily shaded, your roof orientation isn’t optimal, your panels aren’t facing the best angle or your panels are dirty, they won’t perform as well.

Rating Of Charge Controller

As we have calculated above that the charging current for 200Ah battery is 20-22 Amperes , therefore we can use a charge controller about 30-32 Amp.

Note: The above calculation is based on ideal case, so it is recommended to always choose a solar panel some bigger then we need, because, there are some losses occurs during battery charging via solar panel as well as the sunshine is not always in ideal mood.

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Mathematical Formula To Determine How Many Solar Panels You Need

Heres the actual formula, used by EnergySage, that you can use youre hoping to determine how many solar panels youll need:

• Number of panels = system size / production ratio / panel wattage
• Using the numbers weve determined so far, we get:
• Number of panels = 11,000 kW / 1.6 / 300 W

That equates to about 20 to 25 solar panels to do the job. You can use this same formula to determine how many solar panels youll need to power your home. Or, you can use the easier route, which is to look at your energy bill to determine what youll need.

Getting Started With Solar System Sizing

Before you begin to size a solar system, youll want to figure out the main constraints on the project and use those restrictions as the starting point for the design. You can approach the project from one of three angles:

• Budget constraints: Build a system within your target budget.
• Space constraints: Build a system that is as space-efficient as possible.
• Energy offset: Build a system that offsets a certain percentage of your energy usage.

Take into consideration other sizing factors and common stumbling blocks that may impact how to size a solar system:

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Physical Size Of Solar Panels

A 5kW solar system may produce enough energy to power your home, but you may not have enough roof space for a system of that size. Solar panels for households typically come in the standard dimensions of 1.70m x 1.00m, thats around 1.7m2 for every panel installed. However, the wattage output of the panels will likely vary between 250W and 360W for a more efficient module.

As a guide, youll need 4 x 250W panels, or 3 x 330W for every 1kW of your solar system. If youre considering a 5kW system, thats between 15 and 20 solar panels that will require anywhere between 25.5 34m2 of roof space.

Find How Much Energy Solar Panels Produce In Your Area

Now that you know how much electricity your home uses in a month, you need to find the amount of sunlight your area receives. This is usually measured in something called peak sun hours, which is essentially the intensity of sunlight in your area.

You can find the average number of daily peak sun hours for your state here. This number is how much sunlight you receive daily, but we need to know how much you receive monthly. To do this, simply multiply your states daily peak sun hours by 30.

The monthly peak sun hours you get tells you how many kWh of electricity 1 kilowatt of solar panels will produce in your area in one day. So, if your state receives 150 monthly peak sunlight hours, 1 kW of solar will produce 150 kWh of electricity per month.

Not sure about the differences between kW and kWh? Read our guide about kW versus kWh and what they mean.

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How To Calculate Solar Panel Size Needed

If you are looking into purchasing solar panels to be installed on your roof, then you are in for a fantastic experience. They are a brilliant way to provide energy for your home and lower your annual energy bills in one go. Plus, they are environmentally friendly and require hardly any maintenance. However, before you buy, it is important to have a rough idea of the panel size and amount that you will need. Make sure you consult a professional and accredited installer about this, but this page can act as a rough guide.

A Different Way To Figure Out Solar Usage

If youre not interested in doing the math on your own, simply look at your utility bills to figure out how much energy youre using. Doing this allows you to multiply your energy usage by the number of hours of strong sunlight your home gets, then dividing that result by the wattage of the panels youre thinking of installing.

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Solar Panel Output Per Day

Work out how much electricitymeasured in kilowatt hours your panels would produce each day by using this formula:

Size of one solar panel x 1,000

That figure x Efficiency of one solar panel

That figure x Number of sun hours in your area each day

Divide by 1,000

Read more on efficiency below.

To estimate the number of sun hours in your area, use this calculator.

Example

• Divide by 1,000:
• 1,440 ÷ 1,000 = 1.44 kWh per day

*The number of sun hours varies greatly throughout the year , and will be much lower during winter months in particular.

How Much Will It Cost To Install Solar Panels

The cost of solar panels will depend on a number of factors, including the size of your home, the amount of sunlight your location receives, and the type of solar panels you choose. However, on average, you can expect to pay around $10,000-$20,000 for a complete solar panel installation.

There are several ways to finance a solar panel installation, including through a loan or lease agreement. Some utility companies also offer incentives and rebates for installing solar panels. Be sure to research what incentives are available in your area before making a decision about whether or not to install solar panels.

Solar panel technology is constantly improving, so it’s important to shop around and compare quotes from several installers before making a final decision. By investing in solar panels, you can help reduce your carbon footprint and save money on your energy bills.

If you’re considering installing solar panels, be sure to consult with a qualified installer to get an accurate estimate of the costs involved.

We have covered solar panel costing more inthis article, so do check it out!

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Calculate How Many Solar Panels You Need For Your Home

The average American home needs between 19 and 23 solar panels based on the average electricity usage of 877 kilowatt-hours per month. Installing that many solar panels would cost between $13,000 and $16,200 after the federal solar tax credit.

However, chances are your energy usage doesnt line up exactly with the U.S. average, plus the number of solar panels you need depends on several other factors, like the location of your home and what kind of solar panels you choose.

So how exactly do you figure out how many solar panels you need? Weve got you covered.

Calculate how many solar panels you will need to power your specific home

Table Average House Size In Square Feet 10 Us States Compared

Historical values for irradiance can be found for your location on sites like GlobalSolarAtlas.info. The average irradiance value for the USA is 5.322 kWh/m2/day, so Ill use that value of peak-sun-hours for our calculation.

How many solar panels how much solar do I need to power an average house in the USA?

Using average US values, you can find the theroretical solar power output by dividing the daily kWh by the irradiance value in daily peak-sun-hours:

Solar power required = 30000 watt-hours/5.3 peak-sun-hours = 5660 watts

If 300 watt solar panels were used, the number of solar panels for the average US house would be:

5660 watts / 300 watts = 18.86 solar panels

However, all solar PV systems have losses of about 23%. This can be taken into account my multiplying the solar power required by 1.4:

Adjusted solar output = 5660 x 1.4 = 7924 watts

Using 300 watt solar panels, the actual number of solar panels needed would be:

7924 watts / 300 watts = 26 solar panels

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Can I Go Off

When it comes to creating and supplying your own electricity, there is possibly no greener technology more accessible and efficient than solar panels.

For the most part, going off-grid with solar panels is 100% possible. However, it is just one piece to the puzzle.

In order to maintain a healthy prolonged off the grid lifestyle, you will need some place to store all that solar energy generated by your solar panels.

And just like solar panels are the most accessible and efficient for electricity production, solar batteries/solar power stations, are the absolute best technology out there to store your off-grid solar energy.

So in essence, you can go off-grid with solar panels and some sort of storage system.

Solar Panel Size Dimensions

If you refer to the physical solar panel size dimensions, we can start off by saying that each manufacturer has its own optimal dimensions. This largely depends on their own technology.

As you might already know, solar panels are comprised of an arrangement of cells. Depending on the number of cells in the panel they are larger or smaller.

Traditionally, solar panels come in two different configurations: 60-cell and 72-cell. However, if you go to Panasonic or SunPower, they offer 96-cell panels.

But solar energy does not stop in large rigid solar panels.

You can also find small solar panels, and they are ideal to mount on motorhomes, boats, and caravans. Check out our guide on the best boat solar panels.

Solar panels also come in flexible and foldable configurations, making them more practical and easy to carry in case youd like to take them on your hiking or camping trips.

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