How many solar panels are needed to supply electricity to an entire house

Solar energy is a good replacement for a centralized grid. Panels help save your budget, reduce energy costs, and in the long run also help you make money. The battery life is up to 30 years, they do not require complex maintenance and are completely autonomous.

The area of ​​the home indirectly affects the number of batteries that will be needed to fully provide solar energy. The more spacious the house, the greater the number of electrical devices, lighting and heating sources. And the more we need a power generation system. If we take only this into account, in order to obtain the optimal amount of electricity, you need to install batteries at the rate of one element per 10 square meters of the house (approximate number).

If you take an average solar panel power of 300 watts and assume that it produces approximately 1.5 kWh of energy per day (depending on location and conditions), you can roughly estimate how many panels will be needed to cover your energy needs.

In addition to the size of the room, many other parameters influence the number of batteries.

When choosing the number of solar panels for a private home, it is important to consider, first of all, factors such as the power of each panel and the total annual electricity consumption in the house. It is also worth considering what the coefficient of efficiency (COE) of each panel is.

The first factor that affects the number of solar panels is the energy consumed per year. This data can be found in your electricity bills or in your personal account on your company’s website. To determine their exact number, it is better to take data for two to three years. Take into account your future needs: are you planning to add to your family or vice versa, someone will leave your home, are you going to work online.

Estimating the power of the batteries is the next factor that determines how many you will need. The power of one solar panel can be found from its documentation. Most batteries are between 370 and 400 watts. The more powerful the panel, the fewer of them will be needed.

Most panels are about 20% efficient. To calculate efficiency, the actual daily energy output is divided by the rated power of the battery.It is impossible to obtain a one-to-one ratio in this case. After all, in the documentation the rated power of the panel is how much solar energy it can produce in a test version, that is, when creating the most ideal conditions. In reality, the efficiency will be lower, since energy production is simultaneously influenced by several factors: shade, temperature conditions, as well as the angle of the battery, its condition, cleanliness, and how many hours the sun is at its zenith.

These are the main factors. These can include: battery size, number of hours of peak sunlight, roof condition and size. Determine your goals and needs: do you need to fully cover your energy consumption or partially reduce costs.

And based on this data, you can calculate how many panels are needed so that solar energy can fully supply residential premises with electricity.

Once you have calculated how much energy you use per year, the power of solar panels, as well as their productivity factor, it is possible to determine the required number of batteries.

Practice shows that the average efficiency index fluctuates around 1.3–1.6. If it is difficult for you to calculate the productivity coefficient of a solar panel, then you can use option 1.6.

After you have received all the inputs, you need to substitute them into the formula:

Approximate calculation:

Let's say the annual electricity consumption is 9,125 kWh and the solar panel power is 400 W. Moreover, its efficiency is 1.6. In this case we get:

As a result, 15 batteries are needed to convert solar energy into the required amount of electricity.

Another way to calculate:

Peak sun hours are those times when the light intensity is 1,000 watts per square meter. This indicator depends on the geographical location of the home, climate and weather conditions. If we take as an example a consumption of 25 kWh (25,000 Wh) per day, the average peak sunshine time in Cyprus is 5.12 hours per day, the battery power is 400 W, we get the following calculation:

If you round up, that's 13 panels.

This number is approximate, so for an accurate calculation it is better to contact specialists.

The system parameters that are needed in each specific case are easy to calculate. To do this, you need to substitute your values ​​into the formula:

For greater clarity, let’s substitute the data from previous calculations. As a result we get:

When choosing batteries for a private home, as well as their quantity, you should pay attention to seasonal fluctuations. For example, in winter there is less solar energy, and therefore you need to add a small reserve of power to your calculations for such a case, so that at the wrong time you are not left without electricity.

Possible restrictions related to the installation location should also be taken into account. This could be the shadow of buildings or trees that falls on the house, the angle of the roof and its condition. If you take these factors into account when calculating the average number of solar panels for a home, you can get maximum efficiency from the system.

Using solar energy is not only a way to reduce your electricity bills, but also a great contribution to protecting the environment. Our company’s specialists will calculate the cost of installing batteries and possible savings for free. Contact us.