# How Many Solar Panels Do I Need? Calculator Shows Correct Sizing (Free)

Written by Georgette Kilgore

Solar Panels | March 29, 2024

When deciding on a solar panel system for a house, the first question that arises is, how many solar panels do I need?8

The answer is dependent on many factors, including:

• Existing monthly and annual electricity bill
• Existing monthly and annual power usage
• The consistency of the power production
• Daily power usage needs, calculated in kWh per day
• Direct sunlight per day
• Size of the roof in square footage
• The efficiency of preferred solar panel1

These factors all play a role in the size of solar panel you’ll need, as well as how many. Which is why using a solar panel calculator that shows the correct sizing free is such a great time saver.

## How Many Solar Panels Do I Need?

So where to start when answering the question, how many solar panels do I need, is with the calculator of solar panel needs.

### How To Calculate Solar Panel Needs

How to calculate solar panel needs requires the following information: How many hours of direct sunlight is available in the specific state on average every day?

The below table indicates the number of solar hours in the largest cities in every state:

 State City Solar Hours kWh per 1kW Alabama City: Birmingham 5.26 solar hours 1,422 kWh per 1kW City: Huntsville 5.08 solar hours 1,418 kWh per 1kW City: Mobile 5.49 solar hours 1,540 kWh per 1kW City: Montgomery 5.43 solar hours 1,513 kWh per 1kW Alaska City: Anchorage 3.40 solar hours 1,053 kWh per 1kW Arizona City: Flagstaff 6.21 solar hours 1,695 kWh per 1kW City: Phoenix 6.52 solar hours 1,753 kWh per 1kW City: Tucson 6.54 solar hours 1,807 kWh per 1kW City: Flagstaff 6.21 solar hours 1,695 kWh per 1kW City: Phoenix 6.52 solar hours 1,753 kWh per 1kW City: Tucson 6.54 solar hours 1,807 kWh per 1kW Arkansas City: Little Rock 3.40 solar hours 1,401 kWh per 1kW California City: Bakersfield 6.16 solar hours 1,714 kWh per 1kW City: Fresno 5.96 solar hours 1,636 kWh per 1kW City: Los Angeles 6.13 solar hours 1,708 kWh per 1kW City: Modesto 5.96 solar hours 1,652  kWh per 1kW City: Oakland 5.62 solar hours 1,598 kWh per 1kW City: Oxnard 6.04 solar hours 1,702 kWh per 1kW City: Riverside 6.28 solar hours 1,790 kWh per 1kW City: Sacramento 5.83 solar hours 1,620 kWh per 1kW City: Salinas 5.61 solar hours 1,598 kWh per 1kW City: San Bernardino 6.20 solar hours 1,714 kWh per 1kW City: San Diego 5.70 solar hours 1,627 kWh per 1kW City: San Francisco 5.56 solar hours 1,593 kWh per 1kW City: San Jose 5.86 solar hours 1,667 kWh per 1kW Colorado City: Colorado Springs 5.72 solar hours 1,614 kWh per 1kW City: Denver 5.69 solar hours 1,59 kWh per 1kW City: Fort Collins 5.19 solar hours 1,455 kWh per 1kW Connecticut City: Bridgeport 4.63 solar hours 1,307 kWh per 1kW City: Hartford 4.68 solar hours 1,273 kWh per 1kW Florida City: Fort Lauderdale 5.74 solar hours 1,662 kWh per 1kW City: Jacksonville 5.52 solar hours 1,478 kWh per 1kW City: Miami 5.77 solar hours 1,623 kWh per 1kW City: Orlando 5.64 solar hours 1,570 kWh per 1kW City: Tallahassee 5.41 solar hours 1,446 kWh per 1kW City: Tampa 5.76 solar hours 1,610 kWh per 1kW Georgia City: Atlanta 5.26 solar hours 1,470 kWh per 1kW City: Savannah 5.34 solar hours 1,459 kWh per 1kW Hawaii City: Honolulu 5.87 solar hours 1,683 kWh per 1kW

(Image: PhotoMIX-Company17)

 State City Solar Hours kWh per 1kW Idaho City: Boise 5.17 solar hours 1,439 kWh per 1kW Illinois City: Chicago 4.55 solar hours 1,307 kWh per 1kW City: Springfield 4.62 solar hours 1,331 kWh per 1kW Indiana City: Fort Wayne 4.61 solar hours 1,317 kWh per 1kW City: Indianapolis 4.72 solar hours 1,342 kWh per 1kW Iowa City: Des Moines 4.79 solar hours 1,362 kWh per 1kW Kansas City: Kansas 5.04 solar hours 1,464 kWh per 1kW Maryland City: Baltimore 4.83 solar hours 1,437 kWh per 1kW Massachusetts City: Boston 4.72 solar hours 1,339 kWh per 1kW City: Springfield 4.88 solar hours 1,391 kWh per 1kW Michigan City: Detroit 4.60 solar hours 1,325 kWh per 1kW City: Grand Rapids 4.48 solar hours 1,280 kWh per 1kW Minnesota City: Duluth 4.37 solar hours 1,278 kWh per 1kW City: Mpls/St Paul 4.62 solar hours 1,320 kWh per 1kW Mississippi City: Jackson 4.47 solar hours 1,277 kWh per 1kW

(Image: RoyBuri18)

 State City Solar Hours kWh per 1kW Missouri City: Kansas 5.04 solar hours 1,414 kWh per 1kW City: Springfield 5.16 solar hours 1,412 kWh per 1kW City: St. Louis 4.99 solar hours 1,387 kWh per 1kW Nebraska City: Lincoln 5.02 solar hours 1,436 kWh per 1kW City: Omaha 5.02 solar hours 1,425 kWh per 1kW Nevada City: Las Vegas 6.37 solar hours 1,764 kWh per 1kW City: Reno 5.99 solar hours 1,697 kWh per 1kW New Hampshire City: Concord 4.83 solar hours 1,303 kWh per 1kW New Jersey City: Newark 4.74 solar hours 1,313 kWh per 1kW New Mexico City: Albuquerque 6.41 solar hours 1,805 kWh per 1kW New York City: Buffalo 4.34 solar hours 1,221 kWh per 1kW City: New York City 4.58 solar hours 1,310 kWh per 1kW City: Syracuse 4.21 solar hours 1,159 kWh per 1kW North Carolina City: Charlotte 5.18 solar hours 1,419 kWh per 1kW City: Wilmington 5.29 solar hours 1,493 kWh per 1kW North Dakota City: Bismark 4.72 solar hours 1,364 kWh per 1kW Ohio City: Cincinnati 4.68 solar hours 1,301 kWh per 1kW City: Cleveland 4.68 solar hours 1,290 kWh per 1kW City: Columbus 4.57 solar hours 1,296 kWh per 1kW City: Dayton 4.70 solar hours 1,330 kWh per 1kW City: Toledo 4.62 solar hours 1,326 kWh per 1kW

(Image: Kindel Media19)

 State City Solar Hours kWh per 1kW Oklahoma City: Oklahoma 5.54 solar hours 1,579 kWh per 1kW Oregon City: Portland 4.09 solar hours 1,118 kWh per 1kW Pennsylvania City: Philadelphia 4.78 solar hours 1,334 kWh per 1kW City: Pittsburgh 4.46 solar hours 1,210 kWh per 1kW Rhode Island City: Providence 4.74 solar hours 1,334 kWh per 1kW South Carolina City: Charleston 5.38 solar hours 1,489 kWh per 1kW South Dakota City: Sioux Falls 4.88 solar hours 1,441 kWh per 1kW Tennessee City: Clarksville 4.48 solar hours 1,394 kWh per 1kW City: Knoxville 5.00 solar hours 1,397 kWh per 1kW City: Memphis 5.18 solar hours 1,470 kWh per 1kW City: Murfreesboro 4.97 solar hours 1,404 kWh per 1kW City: Nashville 4.91 solar hours 1,390 kWh per 1kW Texas City: Amarillo 6.08 solar hours 1.735 kWh per 1kW City: Dallas 5.50 solar hours 1.552 kWh per 1kW City: Houston 5.33 solar hours 1.476 kWh per 1kW City: San Antonio 5.54 solar hours 1.545 kWh per 1kW Utah City: Salt Lake 5.32 solar hours 1,554 kWh per 1kW Vermont City: Montpelier 4.30 solar hours 1,219 kWh per 1kW Virginia City: Richmond 5.06 solar hours 1,360 kWh per 1kW Washington City: Seattle 3.97 solar hours 1,157 kWh per 1kW City: Spokane 4.38 solar hours 1,228 kWh per 1kW

Entering the solar hours per day into an online solar panel calculator and adding the annual kWh consumed at the premises divided by kWh per 1kW (as indicated in the table), will determine the size of the solar system required.9

Read More About: Carbon Footprint: Solar Panel Manufacturing In 1 Simple Explanation

### How Many kW Hours Does a Solar Panel Produce?

The next question in determining the answer to the question, how many solar panels do I need, is calculating the kW per solar panel.

The majority of solar panels are capable of producing up to 400 watts of power. The real-life output does however depend on direct sunlight, positioning and shading.10

In general, a solar power array consisting of 30 solar panels would be more than sufficient to power a residential home.

The below table indicates the minimal, maximum, and average electricity output of popular solar panel brands (in Watts):

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output Amerisolar 240 W (Output) 330 W (Output) 285 W (Output) Astronergy 350 W (Output) 370 W (Output) 360 W (Output) Axitec 250 W (Output) 385 W (Output) 302 W (Output) BenQ Solar (AUO) 250 W (Output) 295 W (Output) 277 W (Output) Boviet Solar 320 W (Output) 340 W (Output) 330 W (Output)

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output Canadian Solar 225 W (Output) 410 W (Output) 320 W (Output) CentroSolar 250 W (Output) 320 W (Output) 278 W (Output) CertainTeed Solar 70 W (Output) 400 W (Output) 308 W (Output) ET Solar 255 W (Output) 370 W (Output) 306 W (Output) First Solar 420 W (Output) 460 W (Output) 440 W (Output)

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output GCL 310 W (Output) 330 W (Output) 320 W (Output) Grape Solar 160 W (Output) 285 W (Output) 237 W (Output) Green Brilliance 230 W (Output) 300 W (Output) 266 W (Output) Hansol 250 W (Output) 360 W (Output) 304 W (Output) Hanwha 365 W (Output) 385 W (Output) 375 W (Output)

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output Heliene 250 W (Output) 370 W (Output) 306 W (Output) JA Solar 260 W (Output) 410 W (Output) 329 W (Output) JinkoSolar 315 W (Output) 410 W (Output) 367 W (Output) Kyocera 260 W (Output) 330 W (Output) 295 W (Output) LG 315 W (Output) 415 W (Output) 365 W (Output)

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output LONGi 305 W (Output) 455 W (Output) 387 W (Output) Mission Solar Energy 300 W (Output) 390 W (Output) 334 W (Output) Mitsubishi Electric 270 W (Output) 280 W (Output) 275 W (Output) Neo Solar Power 310 W (Output) 330 W (Output) 320 W (Output) Panasonic 320 W (Output) 370 W (Output) 340 W (Output)

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output Peimar 310 W (Output) 310 W (Output) 310 W (Output) Peimar Group 270 W (Output) 330 W (Output) 301 W (Output) Phono Solar 260 W (Output) 350 W (Output) 294 W (Output) QCELLS 285 W (Output) 430 W (Output) 358 W (Output) REC 275 W (Output) 450 W (Output) 347 W (Output)

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output RECOM 265 W (Output) 370 W (Output) 308 W (Output) Recom Solar 310 W (Output) 350 W (Output) 330 W (Output) ReneSola 245 W (Output) 320 W (Output) 277 W (Output) Renogy Solar 250 W (Output) 300 W (Output) 268 W (Output) RGS Energy 55 W (Output) 60 W (Output) 58 W (Output)

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output Risen 270 W (Output) 390 W (Output) 329 W (Output) S-Energy 255 W (Output) 385 W (Output) 334 W (Output) Seraphim 255 W (Output) 340 W (Output) 294 W (Output) Silfab 300 W (Output) 390 W (Output) 335 W (Output) Solaria 350 W (Output) 430 W (Output) 375 W (Output)

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output Solartech Universal 310 W (Output) 325 W (Output) 318 W (Output) SunPower 320 W (Output) 435 W (Output) 355 W (Output) SunSpark Technology 310 W (Output) 310 W (Output) 310 W (Output) Talesun 275 W (Output) 415 W (Output) 365 W (Output) Talesun Solar Co. 400 W (Output) 400 W (Output) 400 W (Output)

 Solar Panel Manufacturer Minimum Output Maximum Output Average Output Trina 265 W (Output) 415 W (Output) 337 W (Output) Trina Solar Energy 260 W (Output) 320 W (Output) 288 W (Output) Upsolar 270 W (Output) 365 W (Output) 311 W (Output) Vikram Solar 320 W (Output) 340 W (Output) 330 W (Output) Winaico 325 W (Output) 340 W (Output) 332 W (Output)

### Solar Power Calculation Formula

Calculating the energy produced by a solar panel can be done by implementing the following solar power calculation formula:11

5 hours of direct sunlight x 290 watts (premium panel wattage) = 1,450 wh or 1.5 kWh.

This means that the total output of a single solar panel would be around 550 kWh every year.

### Solar Panels kWh Calculator

A solar panel kWh calculator takes into account the solar cell efficiency as well as the size of the solar panel.

When calculating the kWh of an entire solar panel array, the above example can be employed:

5 hours of direct sunlight + 30 solar panels on the roof (290 W each) = 8.7 kW system.

If the 5 solar hours are multiplied by 8.7 kW, it equals 43.5 kWh of electricity production per day.

Furthermore, if 43.5 is multiplied by 365 days, it equals 15,800 kWh of electricity production per year.

This should be more than sufficient for a residential home, as the average electrical energy consumption per household in the US is around 10,600 kWh.2

## 60 kWh Per Day Solar System

A 60 kWh per day solar system (6 kW system) is one of the most common solar systems in the US.12 A 60 kWh per day solar system is capable of producing up to 900 kWh per month. This is sufficient for many households, considering that the average US household consumes around 893 kWh of electricity every month.

However, it may not be a one-size-fits-all solution, because different households consume electricity in different ways.

Among the renewable energy sources, solar has the least amount of carbon emissions produced. Regardless, everyone has a personal carbon ecological footprint and can measure it using a calculator.

## How Many Solar Panels For 60 kWh Per Day?

A common question about a 60 kWh per day solar system is, how many solar panels for 60 kWh per day?

A 6 kW system requires on average between 16 and 18 solar panels, depending on the watt output per panel.3

## 70 kWh Per Day Solar System

A 70 kWh per day solar system with 275 – 320 W solar panel output will require between 25-28 solar panels.

In general, a single solar panel measures 1.7m2, which means the roof area required is around 48m2.

## How Many Solar Panels Do I Need?

Tying in with the question, how many solar panels do I need, is the common question, how many solar panels to power a house?

The answer depends on energy usage, solar hours, and the brand of solar panels.

## How Many Solar Panels To Power A House?

How many solar panels to power a house depends on:13

• The required electricity
• Solar hours
• Wattage per panel

Existing electricity usage should be calculated by combining a full year’s consumption and dividing it by 12.

Daily peak sun hours per month is determined by multiplying the particular state’s solar hours by 30. If the state receives 150 solar hours, 1 kW of solar will be sufficient to produce 150 kWh of electricity each month.

Monthly electricity consumption should then be divided by the solar hours to find the exact solar system size required in kW.

The example is as follows:

893 kWh consumed energy / 135 monthly solar hours = 6.61 kW of solar power

### How Many Solar Panels Do I Need For A 4-Bedroom House?

The next question then is, how many solar panels do I need for a 4-bedroom house?

Once the size of the required solar system is determined, the size can be multiplied by 1,000 to convert the size from kW to W.14

The same example: 6.61 kW solar x 1,000 = 6,610 W of solar

Then the system size (in watts) can be divided by the watts of the solar panels. (The average US solar panel is 370 W.

6,610 W solar / 370 W panel = 18 panels

An average 4-bedroom house in the US would require a 7.75 kW solar array, consisting of 375 W panels. The number of panels would be around 21.4

The below table indicates the number of panels required per typical bedroom size:

 Number of bedrooms Average system size Number of panels (375W) Number of panels (315W) 1 bedroom 1.94 kW 6 panels 7 panels 2 bedrooms 3.88 kW 11 panels 13 panels 3 bedrooms 5.82 kW 16 panels 19 panels 4 bedrooms 7.75 kW 21 panels 25 panels 5 bedrooms 9.69 kW 26 panels 31 panels 6 bedrooms 11.63 kW 32 panels 37 panels

### Solar Panel Sizing Calculator

A solar panel sizing calculator requires the following inputs:

• Battery type + configuration
• Chosen solar array configuration
• Type of solar panels
• Inverter type
• Feedback should then be tweaked according to personal requirements5

### How Many Solar Panels Do I Need For 400 kWh Per Month?

How many solar panels do I need for 400 kWh per month:15

• 8 panels (375 W per panel)
• 10 panels (315 W per panel)

### How Many Solar Panels Do I Need For 500 kWh Per Month?

How many solar panels do I need for 500 kWh per month:

• 10 panels (375 W per panel)
• 12 panels (315 W per panel)

### How Many Solar Panels Do I Need For 700 kWh Per Month?

How many solar panels do I need for 700 kWh per month:

• 14 panels (375 W per panel)
• 16 panels (315 W per panel)

### How Many Solar Panels Do I Need For 1500 kWh Per Month?

How many solar panels do I need for 1500 kWh per month:

• 28/29 panels (375 W per panel)
• 34/35 panels (315 W per panel)

### How Many Solar Panels Do I Need For 3000 kWh Per Month?

How many solar panels do I need for 3000 kWh per month:

• 58 panels (375 W per panel)
• 69 panels (315 W per panel)6

### How Many Solar Panels Do I Need For 4,000 kWh Per Month?

How many solar panels do I need for 4,000 kWh per month:

• 29 panels (375 W per panel)
• 34 panels (315 W per panel)

### How Many Solar Panels Do I Need For 5000 kWh Per Month?

How many solar panels do I need for 5000 kWh per month:

• 36 panels (375 W per panel)
• 43 panels (315 W per panel)

## How Many Solar Panels Do I Need Calculator?

How many solar panels do I need calculator:16

• Energy consumption in kWh per year
• Solar hours per day
• Bill offset in percentage
• Environmental factor in percentage
• Solar system size (estimated)
• Required roof area (in m2)
• Number of panels required
• Required area in m27

Using the above information and solar calculators will provide a definite answer to the question, how many solar panels do I need?

## How Much is the Average Per Month Solar System Cost of a Residential Solar Array?

The average cost of a residential solar array is around \$2.94 per W.

## How Much Kw Solar Panel Required For Home?

An average household in the US that consumes 1000 kWh would require 26-30 panels of 320 W each.

## How Many Solar Panels Do I Need?

Calculating the required number of solar panels is dependent on the following calculation: Household hourly consumption x solar hours by area divided by the panel wattage.

## References

1Coastal Solar. (2022, August 9). Find How Many Solar Panels You’ll Need – In 8 Easy Steps. Coastal Solar. Retrieved November 20, 2022 from <https://coastalsolar.com/many-solar-panels-will-need/>

2Aggarwal, V. (2022, November 1). What is the Output of a Solar Panel? | EnergySage. EnergySage Blog. Retrieved November 20, 2022 from <https://news.energysage.com/what-is-the-power-output-of-a-solar-panel/>

3guide, s. (2021, December 28). How Much Electricity Does a Solar Panel Produce? SolarReviews. Retrieved November 20, 2022 from <https://www.solarreviews.com/blog/how-much-electricity-does-a-solar-panel-produce>

4SolarReviews. (2022, August 19). How Many Solar Panels Do I Need? | Solar Calculator. SolarReviews. Retrieved November 20, 2022 from <https://www.solarreviews.com/blog/how-many-solar-panels-do-i-need-to-run-my-house>

5TheSunPays. (n.d.). Solar System Sizing Tool & Calculator – TheSunPays. TheSunPays. Retrieved November 20, 2022 from <https://shop.thesunpays.co.za/pages/solar-system-sizing-calculator>

6Unbound Solar. (2019, November 26). How many solar panels do I need to power my home? Unbound Solar. Retrieved November 20, 2022 from <https://unboundsolar.com/blog/how-many-solar-panels-to-power-my-home>

7Raman, M., & Darcy, M. (2022, November 4). Solar Panel Calculator. Omni Calculator. Retrieved November 20, 2022 from <https://www.omnicalculator.com/ecology/solar-panel>

8Office of ENERGY EFFICIENCY & RENEWABLE ENERGY. (2022). Solar Rooftop Potential. Department of Energy. Retrieved November 20, 2022, from <https://www.energy.gov/eere/solar/solar-rooftop-potential>

9Tennessee Valley Authority. (2022). Tennessee Valley Solar Calculator. Tennessee Valley Authority. Retrieved November 20, 2022, from <https://edt.tva.gov/>

10Government of India. (2022). Ministry of New and Renewable Energy. National Portal for Rooftop Solar. Retrieved November 20, 2022, from <https://solarrooftop.gov.in/rooftop_calculator>

11ESRL Global Monitoring Laboratory. (2022). NOAA Solar Calculator. ESRL Global Monitoring Laboratory. Retrieved November 20, 2022, from <https://gml.noaa.gov/grad/solcalc/>

12NREL PVWatts Calculator. (2022). Solar Resource Data. PVWatts Calculator. Retrieved November 20, 2022, from <https://pvwatts.nrel.gov/pvwatts.php>

13United States Government. (2022, August 31). Deciding Whether to Install Solar Panels on Your Home? A New NIST Web Tool Can Help. National Institute of Standards and Technology. Retrieved November 20, 2022, from <https://www.nist.gov/news-events/news/2022/08/deciding-whether-install-solar-panels-your-home-new-nist-web-tool-can-help>

14Gov.uk. (2022). Solar photovoltaic (PV) cost data. GOV.UK. Retrieved November 20, 2022, from <https://www.gov.uk/government/statistics/solar-pv-cost-data>

15Government of India. (2022). Schemes. MNRE. Retrieved November 20, 2022, from <https://mnre.gov.in/solar/schemes>

16United States Government. (2022). Solar Power for Your Home. Federal Trade Commission | Consumer Advice. Retrieved November 20, 2022, from <https://consumer.ftc.gov/articles/solar-power-your-home>