Solar Calculator

Climatebiz has worked with thier in-house energy experts and developers to create a unique solar calculator which assists you in sizing the correct solar system based on your home’s location, roof direction/tilt angle, and the amount of electricity you consume each month. 

Use our solar calculator below to determine the solar system size your home requires:

Solar Panel Calculator

On average, U.S. homeowners can save about $1,500 a year by installing solar panels – $37,500 over the lifespan of a solar system. Do you want to find out how much you could save with solar? Click the button below and complete 5 simple steps to get your free personalized solar savings estimate.

How To Use Our Solar System Calculator

1. Insert your home’s ZIP code 

With this information, we can determine your location’s Global Horizontal Irradiation, also known as peak sun hours. A peak sun hour equates to 1 hour in which the sun’s solar irradiance (sunlight) produces an average of 1000 W/m². Anything over 4 hours daily is considered great for solar energy production. The more peak sun hours your location has, the better equipped it is for solar panels. 

2. Insert the pitch of your roof

Most roofs have a sloping pitch of between 18.4° and 36.9°. The best roof pitch angle for solar panels is between 30 – 40°. At these low angles, enough surface area of the photovoltaic cells will be exposed to the sun’s irradiation. Thus, generating sufficient amounts of solar energy.

3. Insert the direction of your roof

This input can significantly affect your solar calculator’s value outcome. If your home is located in the Northern Hemisphere, you ideally want your panels facing towards the true south, and if you are located in the Southern Hemisphere, you want your solar panels facing true North.

4. Enter your monthly electricity consumption

This metric allows our solar calculator to recommend the best solar system size to offset your energy consumption. You can find your home’s monthly kWh consumption on your utility bill. 

5. Select a solar panel power rating

This allows our solar calculator to determine how many solar panels your home will need and how much space your overall solar system will require. The most common solar panel power ratings for residential installations are 370 watts, 400 watts, and 500 watts

How Our Solar Panel Calculator Works

Solar Resource Data

Solar resource data is solar irradiance and meteorological data that describe the conditions at the location of your home’s solar system. The Climatebiz solar calculator uses hourly typical meteorological year (TMY) data from the NREL National Solar Radiation Database (NSRDB). 

Module Type

Our solar calculator assumes that you install monocrystalline solar panels with a nominal efficiency of 19% and a temperature coefficient of -0.35 %/°C.

Array Type

Our solar calculator automatically assumes you are installing a fixed roof mount solar system. Most residential installations utilize this array type. At a later stage, we may include the option to select between a ground-mount, one-axis, and two-axis solar array. 

System Losses

Included in our calculators model equations is the performance losses you would expect in a real solar system. The default value we use for system losses is 12% and is based on the categories below:

  • Soiling: 2%
  • Shading: 3%
  • Snow: 0%
  • Mismatch: 2%
  • Wiring: 2%
  • Connecting: 0.5%
  • Light-Induced Degradation: 1.5%
  • Nameplate Rating: 1%

Tilt Angle

Think of tilt angle as the angle from horizontal of the photovoltaic modules. For most fixed solar panel arrays, the tilt angle is the angle from horizontal of the array where 0° = horizontal and 90° = vertical. Best practices include setting the tilt angle to the latitude of the system’s location. Doing this will maximize the system’s total electrical output over the year.


Upon calculation, our solar calculator displays annual and monthly energy production estimates in kilowatt-hours, along with the monthly and annual average peak sun hours (kWh/m2 per day) located in your area. It also displays the estimated roof area required for your recommended solar system.

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  1. Wouldn’t it had be easier to put numbers 0.98so (for soiling) or such not (1-0.002) would make much easier to understand

    • Hey Michael, thanks for the feedback. We’ll be releasing an upgraded version of our solar calculator next month and we’ll take your comment into consideration.

      Is there anything else you’d like to see in the calculator?

  2. Compared this to my 4.8 kW tesla system. Unfortunately my roof has both east and west facing. Actual production for my june was 877kwh. But overall your calculations were pretty spot on. Great job!

    • Avatar
      Kyle Browning July 19, 2022 at 9:49 pm

      Thanks David, let us know if there is anything more you’d like to see in a future solar calculator update.

  3. What about ground mount? You don’t include that for calculation, why not?