How To Calculate the Efficiency of Solar Panels for Your Home Without Too Much Effort?

Solar Panels

Homeowners who have decided to install solar systems face several questions at once. Determining the energy production rate needed to provide electricity to the home is one of them. This is an essential feature to pay attention to. After all, it ensures the return on investment and the correct selection of systems of all features.

According to EnergySage research, it takes 17-21 solar panels to cover the energy needs of a typical home. However, these indicators may change, as several factors must be used for the calculation in each case. We suggest you learn about the main ones and understand how to create a calculation formula from them.

Solar PV Efficiency: How to calculate the cell and module efficiency

What Factors Are Important for Solar Panel Calculations?

Solar panel systems are an inexpensive purchase that is designed to last. That is why it is necessary to be responsible for the choice of such structures. First, you should decide on the installation provider. To do this, you can search for it by searching for “solar companies near me”, then compare their conditions and choose the best offer according to your requirements.

Identifying the number of solar panels needed for the home’s systems is the next step. It should be noted that this indicator is determined individually. There is nothing complicated in this, but some calculations will still have to be performed. Several characteristics must be used in the process.

The Level of Quality of Solar Panels

On sale, you can find dozens of varieties of solar systems from different companies. It may seem that they are all the same, however, the designs have several differences. After all, manufacturers use different technologies and materials.

If you want to choose reliable, durable, and productive solar panels for yourself, then you should consider the products of proven companies. Such structures usually have higher efficiency indicators, so you can save on their number.

Annual Energy Consumption of the House

This indicator is extremely important, as it will help to quickly determine the efficiency of solar electricity. It is very easy to find out the amount of annual electricity consumption. It is enough to review your account for the previous year.

If it is difficult to obtain such data, you can use the usual formula. The monthly consumption figure must be multiplied by 12. However, the figures may differ, so you should contact the relevant services and find out the exact data.

Correlation of Panel Type and Performance Level

When performing solar panels efficiency calculation, you should also pay attention to the type of solar panels. The level of system productivity depends on this direction. There are currently 3 varieties on sale:

Amorphous The efficiency level is 8-12%
Polycrystalline The productivity of the specified structures is at the level of 15-19%
Monocrystalline In the case of monocrystalline models, the efficiency is 16-23%

As can be seen from the indicators, mono- and polycrystalline solar systems provide the best results. Amorphous varieties are currently almost not in use due to their short service life and low level of efficiency.

Also read: Find the Best Solar Energy Company for Your House

Total Power

A system’s total capacity to generate electricity must also be taken into account when calculating solar panel power. It is called the power level. This value is calculated in Watts and is determined by a simple formula. The total power is equal to the sum of the powers of all the solar panels that make up the installation.

One such component usually produces 300 to 400 watts. If you want to install 5 such units, you will receive a structure with a power of 1500 or 2000 W, respectively. However, one should not forget that the manufacturer indicates such an indicator because of optimal lighting conditions. That is, the numbers correspond to the values when sufficient solar radiation is provided.

Features of the Roof

Solar panel output calculation is not possible without taking into account the slope and orientation of the roof. The level of efficiency depends on these characteristics. Professionals recommend installing solar panels facing south. In this case, maximum performance indicators are ensured. If the solar panels are placed in a different position, the level of efficiency can drop from 1 to 20%.

Under these conditions, more solar panels may be in need to generate enough electricity to power all household systems. In addition, the angle of inclination is important. For best results, you need to install the panels at an angle so that they provide maximum results at any time of the year.

Geographical Location of the House

If you want to calculate solar panel efficiency over time, then in the process you also need to use data about geographic location. Lighting conditions vary from state to state, so it’s worth choosing systems with the appropriate performance.

For example, in one of them, the structures will produce 1300 kW per hour per 1 m2, and in the other – 1750 kW per hour per 1 m2. This means that more modules need to be installed where lighting conditions are not optimal.

How Many Solar Panels Should Be Placed in the House?

To determine this figure, it is worth using all the listed criteria. However, you can focus mainly on the indicators of annual electricity consumption in the house. Here is an approximate ratio of this data to the number of solar panels.

Number of solar modules The volume of annual electricity consumption
16-20 8-10 thousand kW per hour
10-15 6-8 thousand kW per hour
7-9 4-6 thousand kW per hour
4-6 2-4 thousand kW per hour
2-4 Less than 2 thousand kW per hour

If it is difficult to navigate these indicators, then you can choose the average value. Experts indicate that most homeowners install between 4 and 17 modules of solar systems. In addition, a simple formula can be used to calculate the number of solar panels.

It consists in using 3 main indicators: the production coefficient, the power of the solar panels, and the amount of electricity used. To calculate the required number of panels using these indicators, you need to divide the total power by the production factor and the panel power. This method is usually used by specialists of companies engaged in the production of solar systems.


Calculation of the number of solar panels is an important indicator that is necessary in the process of purchasing installations. That is why it is quite essential to learn to define it taking into account certain factors. The values are the annual amount of electricity consumption, the geographical location of the house, the slope of the roof, the total power of the systems, and the technology by which the solar panels are made. However, an easier and better solution may be to contact specialists or use a special calculator on company websites.

Written by
Barrett S

Barrett S is Sr. content manager of The Tech Trend. He is interested in the ways in which tech innovations can and will affect daily life. He loved to read books, magazines and music.

Leave a comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Articles

Augmented Reality

Exploring the World of Augmented Reality: Applications and Future Prospects

Augmented reality (AR) has transcended the realm of science fiction, becoming an...

Wife's Instagram Messages

How Can You Track Your Wife’s Instagram Messages

From a platform for sharing photographs and stories to a place to...

OCR Document

A Complete Guide on Using OCR to Digitize Your Documents

To save, retrieve, and share information efficiently in this increasingly digital environment,...

Large PDF Compressor

Small Size, Big Impact: The Benefits of Compressed PDFs for Businesses

Businesses rely heavily on electronic documents for their daily operations. Portable Document...