How To Size My Solar Panel System?

It’s crucial to consider the size of your property when calculating how many solar panels you’ll need. To fully offset their electricity demand, the average homeowner would require 28 to 34 solar panels. Based on the size of your home, the chart below provides an estimate of how many panels you could require.

Divide the size of your solar system by the wattage of each panel to get the number of panels you’ll need (which averages around 320 watts).

If you want a 4 kW system, for example, divide 4 kW (or 4,000 watts) by 320 watts to get 12.5. Round up to 13, which is the number of panels you’ll require.

You can also figure out how many panels you’ll need for each appliance separately. This method is advantageous if you need to add panels due to increased usage or while purchasing a new appliance.

Divide the appliance’s average annual wattage by the panel wattage to arrive at this figure. A 600 kWh refrigerator, for example, would require two solar panels (600 / 320).

Calculate Your kWh Usage

  • Take a look at your electric bill to see how many kilowatt-hours (kWh) you used. To look at peaks and valleys in usage across a year, you’ll need a complete year’s worth of data. The use of your A/C and heating systems increases your energy consumption in the summer and winter.
  • Calculate your average monthly kWh consumption. To calculate your average monthly use, add up your kWh usage over the last 12 months and divide by 12. In the summer, when the sun is at its strongest, your grid-tied system will likely to overproduce.

Use our home appliances power consumption table to find out how many kWh your appliances would use per month to better evaluate your home’s energy usage.

The energy your system creates can be banked with your utility as a credit that can be used later if your utility has a favorable net metering policy. Check with your local utility company to see if they will give you credit.

Look Up Your Peak Sun Hours

The average peak solar hours vary a lot depending on where you live and how hot it is. To get the most of solar electricity, you’ll need to figure out how many peak hours of sunlight you’ll get:

  • Look up your peak sun hours on a sun hours chart to see how many hours per day the sun produces the most sunshine.
  • Write down the daily average of peak solar hours in the city closest to you.

Calculate the Size of Your Solar System

To determine the size of your solar system, multiply your daily kWh energy need by your peak sun hours to get the kW output. Then divide the kW output by the efficiency of your solar panels to get an estimate of how many solar panels you’ll need for your system.

For my home, how many kW solar panels do I require?

So, how many solar panels do you need to power a home based on these factors? You’ll need to figure out two things to estimate how many solar panels you’ll need without a professional assessment: how much energy you use and how much electricity your panels will produce.

Calculating How Many Kilowatt-Hours Your Home Uses

The average American home uses 10,649 kWh of energy per year, according to the latest figures from the US Energy Information Administration (EIA). This, however, differs from state to state. Consider the following scenario:

Add up the kWh indicated on your last 12 power bills to get a better idea of how much energy you consume annually. The size of your home, the number of occupants, your electricity usage patterns, and the energy efficiency rating of your home gadgets will all influence these figures.

Solar Panel Specific Yield

After you’ve calculated how many kWh your home needs annually, you’ll need to calculate how many kWh each of your solar panels produces over the course of a year. This will vary depending on the type of solar panel used, the roof’s characteristics, and the location’s peak sunlight hours.

In the solar power industry, a common metric used to estimate system capacity is “specific yield or “specific production. This is the annual kWh of energy produced for each kilowatt of installed solar capacity. The amount of sunshine accessible in your location has a big impact on your yield.

Check credible sources like the World Bank solar maps or the National Renewable Energy Laboratory’s solar radiation database to obtain a better sense of the specific yield that can be attained in your location. Divide your annual kWh usage by the specific yield per kilowatt of solar capacity to find how many kW are required to power a home.

For example, if your home uses 15,000 kWh of energy per year and solar panels in your area produce 1,500 kWh/kWp, you’ll need a system with a capacity of roughly 10 kilowatts. Paradise Energy Solutions has also devised a general formula for estimating the size of solar panel system you’ll require.

Simply multiply your annual kWh by 1,200 to get the required solar capacity in kilowatts. So, if your total energy consumption during the last 12 months is 24,000 kWh, you’ll require a 20 kW system (24,000 / 1,200 = 20).

How much should my solar system be oversized?

A reasonable rule of thumb when constructing your system is that your solar panels should be 10-20% larger than your inverter. Due to higher efficiency losses from heat in warmer climes, this can be extended up to 30%.

We commonly couple the 290W Enphase IQ7+ micro-inverter with a solar panel in the 320W-350W range for micro-inverters.

The SolarEdge HDWave 7.6kW string inverter can be used with a solar array ranging from 8360W to 9120W. On a 7,600-watt inverter, for example, you might utilize three strings of 335W panels, each with nine panels, for a total of 9,045 watts.

In both situations, the manufacturers offer a considerably wider range of panelsEnphase recommends 235W-440W panels for the IQ7+, while SolarEdge specifies a maximum of 11,800 watts for their 7.6kW HD-Wave. These parameters specify what the inverters can safely handle, however we propose the tighter ranges above to assist users get the most out of their system for the money they spend. Keep in mind that this will vary based on your environment and other production-related factors.

For 2000 kWh per month, how many solar panels do I need?

A monthly energy use of 2000 kWh equates to approximately 66 kWh per day. The solar panels you install must produce 66 kWh per day and 2000 kWh per month to offset 100 percent of this energy demand.

A solar energy system capable of producing 2000 kWh per month would be made up of 27 to 66 conventional home solar panels. The amount of solar power you require, or the number of solar panels you require, is mostly determined by your location.

For example, a person in Colorado Springs, CO would need 34 330 watt residential solar panels, whereas a person in Columbus, OH would need roughly 44 of the same solar panels to provide 2000 kWh of energy per month (on average).

For a residence of 2000 square feet, how many solar panels do I need?

People frequently inquire about the number of solar panels they will require dependent on the size of their property. However, for solar electric system design, the amount of electricity you use is more significant than the size of your home. This is primarily due to the wide range of ways in which people consume power.

Let’s imagine two family dwell in 2,000 square foot houses next door to each other. A young man and his fiance live in Home A; they both work long hours and frequently socialize with friends in the evenings. As a result, they use very little electricity and only pay around $40 each month.

Two parents and their two teenage children live in Home B. They are either using power to filter their pool or operating the heater or air conditioner, while the teenagers are always on their iPads, opening the refrigerator, or watching TV. Because there are more people living in the residence and their lifestyle necessitates more energy, their monthly electricity expenses are around $325.

Despite the fact that they live in identical homes, the family in Home B would most likely need to invest in more solar panels to reduce their electricity consumption than the couple in Home A.

Even if the residences consumed the same amount of electricity, one may have better solar exposure or less shade than the other, resulting in more or less panels.

The quantity of energy you use now is also significant because most utility companies in Los Angeles and Orange County limit the size of your solar system based on how much energy you use now. This figure is usually calculated by looking at how much electricity you used in the previous year.

There are, of course, certain exceptions to the rule. If you’ve just been in your home for a few months or want to put solar panels on a property that’s still being built, most utility companies will let us estimate your usage based on the square footage of your home.

The Los Angeles Department of Water and Power, for example, calculates this type of average as 2 watts per square foot. A 4,000-watt solar array would be authorized for a 2,000-square-foot residence. A system of this size could range from 12 to 18 solar panels, depending on the type of panel you choose. Keep in mind that the formula for estimating usage differs based on your electrical provider.

Another exception is sometimes allowed for persons who anticipate an increase in their electricity consumption. We can estimate the additional demand and put it into the solar panel design and cost if you plan to buy an EV (electric car) or install central air, for example. The utilities, on the other hand, are finicky! They’ll require proof of purchase in addition to the solar system application.

For 1000 kWh per month, how many solar panels do I need?

A solar panel system that produces 1,000 kWh per month is required. 24.69 solar panels = 1000 kWh / 40.5 kWh Whew! We arrived at our conclusion after a lot of arithmetic.

What is the daily output of a 5kW solar system?

In extremely cloudy conditions, a 5kW solar system is quite likely to produce less than 1kW.

The majority of solar PV inverter brands will display Daily kWh, Energy Today, or something similar. If necessary, see your inverter’s handbook. This is the total quantity of energy your system has produced since it began in the morning.

There are numerous elements to consider in order to precisely anticipate how much energy your solar system will produce each day. However, there is a VERY basic formula that will give you an approximate estimate.

That’s all there is to it! As a result, a 5kW solar system should produce roughly 20kWh per day on average. You’ll probably notice a lot more power produced on brilliant solar days in the summer, perhaps up to 30kWh, and a lot less power produced during cloudy winter days, perhaps less than 10kWh. However, over the course of a year, it should average roughly 20kWh. You don’t have to be out there with a pen writing it all down, but if you want to check the daily total shortly before dark, that’s fine. Divide the result by four to get a number that is near to the size of your solar array.

If you believe your system isn’t operating well, you should consider cleaning your solar panels. If that doesn’t solve the problem, call your solar installer to see what else may be done. Check out our article on how to tell if your system is up to par.

For a 10kW system, how many solar panels do I need?

Another popular choice among our residential and commercial customers is the 10kW Solar System. On a daily basis, the 10kW Solar system can extract an average of 37kWh of energy from the sun (see below table 10kW SYSTEM OUTPUT IN MAJOR CITIES). A 10kW Solar System typically includes 27 to 33 panels (depending on the wattage of the Solar panels available; for example, to reach 10kW, you only need 27 of the 370w Solar panels) and a 10kW Inverter. The total solution would contain 27 to 33 CEC Approved Solar Panels, a 10kW CEC Approved inverter (Three Phase), Roof Mounting, and an Australian-approved electrical kit.

What if your solar system is overly large?

When considering solar panel installation, you’ll need to decide how large of a system to purchase. We’ll go over the top reasons to oversize a solar panel system in this article.

Installing a PV array with a rated DC power that is greater than an inverter’s rated AC output power is known as oversizing a PV array, sometimes known as undersizing a PV inverter. It can be a useful tool for system designers that want to supply the most energy for the least amount of money.

An Oversized Solar Panel System Will Produce “Excess Power

Solar panels rarely produce the amount of energy that they are capable of. It is possible to install more panels without sacrificing power. In addition, the increased panel capacity allows the inverter to function at a higher efficiency, virtually making up for the lost capacity. When the total capacity of the solar panels exceeds the capacity of the inverter, the panels are said to be “oversized,” and the inverter is said to be “overclocked.” When your grid operator limits the inverter size you may install, oversizing solar panels can save you money while simultaneously increasing your energy generation. Solar panels produce energy only when they have access to the sun’s rays during ideal weather conditions. Oversized solar panel arrays create more DC power than their inverters can convert to AC power, resulting in wasted energy.

Lower the specific cost of energy delivered

A reduced cost of electricity can be delivered (lower $/kWh) by oversizing a PV array. Oversizing a PV array will raise the system’s PV module and array racking costs. The higher energy generation is achieved at a lower $/kW introduced cost since this can be done without requiring increasing the amount of rating of other balance of system components. As a result, the system’s specific cost of energy delivery is reduced. The yearly energy generation of a system can be enhanced by more than 28 percent by oversizing a PV array with a 5kW inverter for just a 10% increase in the overall cost of installation, according to a Sunny Design comparison.

Reduce inverter costs

The DC energy output of a PV array can be better matched to the rated AC power of an inverter by oversizing it. This means that a lower AC rated (and thus cheaper cost) inverter can be used. This can lower the relative cost of inverters when compared to the whole cost of the system.

Achieve favorable energy output when installing inverters in limited space

Due to limits imposed by the owner or local electrical regulations, inverters are often required to be put in specified locations. This may mean that the number of inverters required for a perfectly sized system cannot be installed at a given location. It may be possible to achieve roughly the same annual energy yield with fewer installed inverters by oversizing PV arrays. For example, a 100kW PV array using three Sunny Tripower 25000TL inverters (i.e. 75kW of inverters) would produce around 2% less energy annually than a PV array with four Sunny Tripower 25000TL inverters using Sunny Design (i.e. 100kW of inverters). This translates to an almost 2% reduction in energy output for a 25% reduction in inverters.

Better match the inverter to the PV array, in the event an inverter needs to be replaced

If an inverter fails after the warranty period has expired, it is not always possible to replace it with a similar model. In such circumstances, an inverter with a different AC yield force can be purchased and installed. The existing PV array could be better matched to the inverter’s capacity and the system owner’s replacement cost could be reduced by using an inverter with a lower AC output power.

Make the most of East-West PV arrays

PV arrays are orientated towards the equator in order to maximize energy output (south-facing in theNorthern Hemisphere, north-facing in the Southern Hemisphere). With these optimal direction conditions, the array plane available for putting PV modules may not always be as good as other less ideal array planes. A PV array may be part of some east-facing strings and some west-facing strings in instances when the area accessible for east and west-facing directions is bigger. Because the output power of an east and west PV array peaks at different times, it is possible to vastly enlarge a PV array (example, install a DC input power equal to the inverter AC output power for each of the east and west PV arrays). Taking advantage of an inverter’s scaling capability in this way can result in higher energy output and more consistent AC output on a daily basis.

There are a variety of reasons to install a large PV array. Oversizing a PV array can use an inverter’s rated AC output and give a cheaper cost/watt system, resulting in a lower specific cost of energy produced ($/kWh), because PV arrays rarely operate at their full peak power. When oversizing PV arrays, it’s vital that the inverter’s critical input limits are never exceeded. When trying to design a PV system with an enormous PV array, Sunny Design is the best tool to use. It is critical to follow local electrical requirements consistently and to hire adequately competent system designers and installers.

Is it possible to have too many solar panels?

Is it possible for a solar system to be too big? Yes, the entire array may be too huge for your current power consumption requirements, but this may not be a major issue. Here’s something else to think about.

If your solar array is still connected to the grid, whatever energy it generates that isn’t used by your home or company is fed into the local electricity system.

If this occurs, your local utility company may compensate you with solar credits, which you previously used to pay for energy from the communal grid. So having that problem isn’t such a horrible thing.

The extra energy produced by your solar array evaporates and is wasted if it is not connected to the grid and you are off-grid.