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All you need to know about 20kW Solar System

Updated: Mar 8

Investing in solar can give you a return of 10 to 12.5% per annum in the USA with ZERO risk another good part is that as the charges on grid power increase, your profit in terms of saving will increase too. Thus, what are waiting for? Take a FREE solar survey and start investing in solar today.

However, before investing you have all the right to know the cons and pros of investing in a 20kW solar system. A 20kW solar system can generate power twice more than the average demand in the USA and it requires more space than you could imagine.

Content list:


How much power does a 20 kW solar system produce?

In the US states with peak sun hours between 4.5 and 5, 20kW of solar system can produce 2,700 kWh each month (90kWh per Day). In contrast, 20kW of solar system can produce 1,680 kWh each month (56kWh per Day) in the states where the peak sun hours are between 3.5 and 4. Get a FREE Solar Survey and Check the true potential of your rooftop.

Here peak sun hours differ from daylight hours. Peak sun hours are defined as the time of day when the intensity of sunshine is greatest. In other words, most electricity is generated by solar panels during peak sun hours. Refer below map showing the peak sun hours per day in different states of the US.

Now, for ease of your understanding, we have prepared a map for your quick reference that illustrates how much electricity a 1 kW solar system may produce each day in various US states. >> Refer to the below map.

From the above map, you can calculate how much power your 20kW solar power will generate, or you can do reverse calculations to find out how much solar you need to generate any specific amount of power.


Furthermore, the ability to generate power from solar panels is affected by a variety of additional factors, some of which may also result in a minor loss in the power generation of a solar system. A brief overview of these additional aspects is provided below.

Factors affecting the power generation of the solar system:

The Direction of Your Roof Slope: In the United States a south-facing solar panel, generates the highest amount of power. This is because the United States is located in the Northern Hemisphere of the Earth, and the SUN is always in the southern portion of the sky in the Northern Hemisphere.

Hence installing solar panels on the south-facing slope of your rooftop will generate the highest amount of power.

Installing solar panels on the south-facing slope of your rooftop will generate the highest amount of power.

Furthermore, if you do not have a south-facing rooftop that does not mean that you cannot install solar panels, but that means you will need a slightly higher size of the solar system. However, you need to take a solar survey to find the correct number of solar panels you need.

Shading: Solar panels (or solar cells) that got less sunlight than the others operated as loads, reducing current, output, and efficiency. Determining a shadow-free area on the rooftop is, therefore, necessary before installations.

However, if your rooftop (or part of the rooftop) has some shadow for a short period, then you do not need to worry, you can install solar panels there too.

Roof Angle: The power generating capacity of solar power plants is also impacted by the rooftop inclination angle. Solar systems installed on rooftops with an inclination of 20 to 30 degrees produce less electricity than those with a larger incline angle.

Again, a higher inclination does not exclude the use of solar power, but it does necessitate a larger solar system, the size of which can only be determined by conducting a solar survey.

Dirt: The capacity of solar panels to produce energy is reduced when dusty particles build up on them, which obstruct sunlight. Although you must clean it more regularly, living in a duty neighborhood does not exclude you from using solar power


Without a solar survey, it is challenging to estimate the precise amount of power a solar system can generate on a certain rooftop when all of these factors are considered.


What can a 20kW Solar system run?

A 20kW Solar System can generate 90,000 Wh of power in a day and this much power is enough to run the following loads. Moreover, you will be still left with 16,000 Wh of Power during laundry day and 22,000 Wh during a non-laundry day.

  • Blender - 500 watt (15 Min)

  • Coffee Machine - 1000 watt (15 Min)

  • Dishwasher - 1200 watt (30 Min)

  • Espresso Machine - 800 watt (15 Min)

  • Freezer – Upright – 15 cu. ft. - 1240 Wh/Day (24 Hr.)

  • Fridge – 20 cu. ft. (AC) - 1411 Wh/day (24 Hr.)

  • Kettle – Electric - 1200 watt (15 Min)

  • Microwave - 1000 watt (15 Min)

  • Oven – Electric - 1200 watt (15 Min)

  • Toaster - 850 watt (15 Min)

  • Box Fan - 200 watt (4 Hr.)

  • Ceiling Fan - 120 watt (24 Hr.)

  • Central Air Conditioner – 24,000 BTU NA - 3800 watt (12 Hr.)

  • Water Heater – Electric - 4500 watt (1 Hr.)

  • Well Pump – 1/3 1HP - 750 watt (1 Hr.)

  • Clothes Dryer – Electric - 3000 watt (1 Hr.)

  • Clothes Washer - 800 watt (1 Hr.)

  • Iron - 1200 watt (1 Hr.)

  • TV – LCD - 150 watt 12 Hr.

  • Satellite Dish - 25 watt 12 Hr.

  • Video Game Console - 150 watt 2 Hr.

  • CFL Bulb – 40 Watt Equivalent - 11 watt (x2) 20 Hr.

  • CFL Bulb – 60 Watt Equivalent - 18 watt (x2) 20 Hr.

  • Compact Fluorescent 20 Watt - 22 watt (x2) 20 Hr.

  • Compact Fluorescent 25 Watt - 28 watt (x2) 20 Hr.

  • LED Bulb – 40 Watt Equivalent - 10 watt 20 Hr.

  • LED Bulb – 60 Watt Equivalent - 13 watt 20 Hr.

  • Desktop Computer/Laptop - 200 watt 8 Hr.

  • LCD Monitor - 100 watt 8 Hr.

  • Modem - 7 watt 24 Hr.

  • Printer - 100 watt 15 Min

  • Router - 7 watt 24 Hr.

  • Smart Phone – Recharge - 6 watt 2 Hr.

  • Tablet – Recharge - 8 watt 2 Hr.

Furthermore, many factors can affect the power consumption of a house and the best way to determine the same is by checking the monthly electricity bill.


Solar panels for 20kW solar system

Size of solar panel: The number of solar panels required for a particular solar power system to generate the required amount of power is directly proportional to the rated power of the solar panels you will have, here Higher-power solar panels generate more power and occupy less space. A 400-watt solar panel is 28% bigger than a 250-watt solar panel but it generates 60% more power.

A 400-watt solar panel is 28% bigger than a 250-watt solar panel but it generates 60% more power.

Furthermore, in terms of weight per square foot, 400-watt solar panels are only 24% heavier than 250-watt panels. Hence, going with a 400-watt panel instead of 250-watt will save 60% of space on your rooftop but with a 24% high per-square-foot load. Remember in most cases going with 60% less space is always a good investment than a 24% lesser load. However, to be 100% sure you will need a solar survey to check how much load your rooftop can take.

Now, here is some interesting information on the solar panel size: In every quarter, the rated power of a single solar panel module increases with a slight increase in its dimensions. However, the per-watt cost of the highest-rated single solar module is also the highest. Hence, to find the most optimized price for your solar system you may need to go with a smaller-size solar panel which has been available in the market for the last year. In 2023, 380-watt & 400-watt solar panels are most suitable for rooftop installation.

Type of solar panel: Solar panels are classified into monocrystalline and polycrystalline. Monocrystalline solar panels are more expensive than polycrystalline panels. Monocrystalline, on the other hand, is more efficient and smaller. Hence, monocrystalline panels are most preferable for USA rooftops due to less space and high efficiency.

How many solar panels are for a 20 kW system?

You will need 50 numbers of 400-watt or 53 numbers of 380-watt solar panels for a 20 kW solar power system.

Rooftop area required for the installation of 20kW solar system:

50 numbers of 400-watt solar panels will cover (50x22.7=) 1,135 square feet of rooftop space. However, you cannot cover the whole rooftop with solar panels you need space on a rooftop for the cleaning of solar panels, as per the thump rule you can cover 40 % to 50% of your rooftop with solar panels. Hence, for installing 20 kW of solar system you require 2,270 square feet of house.

However, if you do not have that much space then going with a smaller size solar system will also, help you to overcome high utility bills.


Also Read :


Cost for 20 kW solar system in the USA.

After the detection of the 26% Federal Solar Tax Credit, the per watt price of solar systems in the USA ranges from $2.1 to $ 2.95 depending on the caliber of the tools used in installation and the labor force needed to install it. As a result, the cost of a solar system for a 20 kW solar system in the USA ranges from $42,000 to $59,000. Get a FREE Solar Quote, Now.

Federal Solar Tax Credit: The Solar Investment Tax Credit (ITC), often known as the Federal Solar Tax Credit, is the best solar-related incentive available in the nation. 26% of the entire cost of your solar installation can be deducted from your federal taxes thanks to this incentive.

In addition to the aforementioned, you might also need to spend a little extra for the solar installation because there are a variety of variables that can affect how much a solar system costs, like the rooftop's accessibility and the battery backup. Some of the most important variables are listed below.

Factors affecting the cost of the solar system.

Rooftop type: Solar Installation cost for a flat rooftop is higher than inclined rooftop because a flat rooftop requires more structure and takes more time for installation than an inclined rooftop. However, installing on a rooftop with a higher angle of inclination needed a man-lifter crane, which raised the cost of installation.

Age of Rooftop: An old rooftop may require repairing before the installation of solar panels. Installing, solar panels on rooftops without inspection may lead to much higher repair costs.

Solar inverter type: For rooftop solar systems there are two types of solar inverters are used, that is micro-inverters and string inverters. Micro-inverters are directly mounted on each solar panel, whereas string inverters are mounted in your houses and DC cables from all solar panels are connected to string inverters.

Going with a string inverter is cheap; however, the performance of micro inverters is very much better in terms of efficiency as well as in the expendability of the solar system. Furthermore, string inverters come with 5 years of warranty, whereas micro-inverters come with 25 years of warranty. Hence, in the long term, microinverters are more economical than string inverters.

Battery Backup: If you need a battery, backup with solar for backup power during a power outage then you will need to pay more for the same. The cost to pay for battery backup is subject to the size of the battery bank.


How to choose solar installation company.

Choosing a solar installer in a crowded marketplace is tricky and requires a lot of research. Here we'll tell you how you can find the right solar company in 6 easy steps.

Step #1 Credentials: Always check the credentials of the solar company, a right solar company must have all the credentials required for installing solar systems.

Organizations such as the North American Board of Certified Energy Practitioners (NABCEP) issue industry-standard credentials, which are commonly regarded as the gold standard among renewable energy system installers.

Make certain that the solar installer you select is licensed, bonded, and insured to install residential solar installations in your region. Also, don't forget to ask whether they will use subcontractors on your job and double-check their credentials.

Step #2 Customer service: A great solar installation requires great customer service.

However, depending on only online reviews is not the right parameter to check customer service, because people tend to submit negative experiences more than positive ones.

Hence don’t hesitate to ask for one or two references in your or nearby area that can serve as a reference and if possible visit these sites.

Step #3 Credibility and Expertise: It must have expertise and credibility for installing solar equipment and be knowledgeable about all aspects of the process. A good rule of thumb is to sign with installers who have at least three years of experience.

A good rule of thumb is to sign with installers who have at least three years of experience.

Step#4 Addressing Roof Conditions: When you hire a solar contractor, one of the first things they should do is inspect your roof. Inquire with your installer whether they recommend roof repair before installation. Also, make sure you understand who is responsible for any roof damage or leaks that may occur.

Step #5 Warranties: Before, signing up the company understands how their warranties work, and what the key points of their contracts are. Both the workmanship and installed equipment have different warranty periods. Always, go with the solar company, which has transparencies with their warranty conditions.

Always, go with the solar company, which has transparencies with their warranty conditions.

Step #6 Never select a company only on price: A low-quality solar panel and installation material can make a huge difference. Always choose a solar company based on the feedback and reviews, if a solar company doesn’t have many or any references but quotes are very low, just strikeout them out from your list.

If possible, visit their installed solar system (one old and one newly installed) and talk with the property owner. This will help you to understand their work finishing and how solar makes a change in people's lives.



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