Electricity is expensive, but the tariff varies across different states in India. For example, if you live in Mumbai, you are paying the highest electricity bill in the country.
On the other hand, Delhi, Hyderabad, and the other metros are just slightly behind with their electricity tariff. Is there a way to reduce your electricity bills?
The answer is YES.
You can use alternate modes of generating current, such as solar energy.
India is blessed with an average of 2200 to 3000 hours of sunshine annually, depending on where you live. So every household can generate sufficient electricity by harnessing solar energy. Therefore, you must wonder, ‘How many solar panels are needed to run a house in India.’
Do we have a straightforward calculator?
Unfortunately, the answer is NO because various factors decide the number of solar panels required to power a house in India. Therefore, you require multiple inputs before you can decide on the number.
- How much electricity do you consume for domestic purposes?
- Do you have sufficient space to install these solar panels on your roof?
- How many hours of sunshine does your house get daily?
- What are the wattage and the efficiency of the photovoltaic (PV) solar panels you use?
Solar panel calculator For India
Before we start calculating the number of solar panels you need for your home, let us clarify a few terms for your better understanding.
- The power unit is a watt, and 1000 watts equals one kw. So, for example, if you have a 750 watts motor, it is 0.75 kw.
- One unit of electricity consumed by a house equals one kwh (kilowatt hour). So, for instance, a one kw heater will consume one kwh or 1 unit of power if it runs for one hour.
Let us now see how many power units a one kw solar panel produces
Calculating the power generating capacity of a one kw solar panel is essential to decide on the number of solar power panels needed to run the home. We have seen that India receives 2200 to 3000 hours of sunlight annually. It amounts to 6 to 8 hours daily on average.
Let us assume a conservative figure of 5 hours daily because the sunlight is strongest from 10 am to 3 pm.
We must also account for factors like cloudy days, dust accumulation on solar panels, and shadow formation. That explains why solar panel manufacturers assume an average power loss of around 20%. That leaves us with a figure of 4 hours of peak sunlight.
Therefore, a one kw solar panel will generate four kwh power or four units per day.
Next, a one kw solar panel has three PV panels, each capable of generating 330 wp. So each 330 wp solar panel will generate 330 wp x 4 hours = 1.32 kwh or 1.32 units of electricity per day.
We have done the essential groundwork for calculating the number of solar power panels required for your home. This figure should remain constant on average across India. Of course, some areas in Tamil Nadu, Gujarat, and Rajasthan receive more sunlight hours per day. But, we shall stick to this calculation for everyone’s benefit.
Method of calculating the number of solar panels required for a home in India
You can calculate this figure in two ways. We shall explore both for your benefit.
Method 1
- Collect the electricity bills from January to December for the previous year. Some states have bi-monthly bill generation. Accordingly, you collect the bills for the entire year (12-month period).
- Note down the power units consumed by the household. It will be different every month. For example, you might consume less power in winter because you do not use the AC.
- Add the units and divide them by 12 to get the monthly average power consumption.
- Since a one kw solar panel generates four kwh or four units of power daily, the average monthly generation is 120 units.
- Divide the monthly average power consumption by 120 to get the number of one kw solar panels.
- Finally, multiply the number of one kw solar panels by 1000 and divide the result by 330 wp to get the required solar panels for your home.
Method 2
- Calculate the total electricity consumption for the previous year.
- Divide this figure by 365 to get the average daily power consumption in units.
- Since one kw solar panel produces four kwh of power, divide the average daily consumption by 4 to get the number of one kw solar panels.
- Multiply this result by 1000 and divide it by 330 to determine the number of solar panels required for your home.
Shall we explain this better using a real-life example?
We need not go far to collect data because we shall calculate using my power consumption. FYI, I live in 2000 square feet home (3BH house) in Chennai with two air conditioning units. Here is my bi-monthly energy consumption for 2022.
| Bill Date | Units Consumed |
|---|---|
| 14.02.2022 | 800 |
| 13.04.2022 | 910 |
| 15.06.2022 | 1236 |
| 12.08.2022 | 1000 |
| 15.10.2022 | 1050 |
| 16.12.2022 | 670 |
| Total Units for the year | 5666 |
We shall now calculate the number of solar panels using the abovementioned methods.
| Method 1 | Method 2 |
|---|---|
| Total Annual Consumption = 5666 units | Total Annual Consumption = 5666 units |
| Average monthly consumption = 5666 / 12 = 472 | Average daily consumption = 5666 / 365 = 15.52 |
| Number of one kw panels required = 472 / 120 = 3.93 | Number of one kw panels required = 15.52 / 4 = 3.88 |
| Number of solar panels required = 3.93 x 1000 / 330 = 11.90 | Number of solar panels required = 3.88 x 1000 / 330 = 11.76 |
| Thus, the total number of panels required for my home is 12. | Thus, the total number of panels required for my home is 12 |
How much will a solar rooftop project cost?
The cost of installing a rooftop solar power plant depends on its size. For example, we have seen that my house requires 12 panels, entailing the installation of a four kw solar plant.
Consumers can use this calculator to refer to the MNRE current benchmark cost and determine the total project cost.
The factors affecting the project cost include your rooftop area, the solar panel capacity, and your budget. Subsidies and loan facilities are available for installing solar rooftop projects.
Frequently Asked Questions on Solar Panels for Home
Generally, a one kw solar system with three solar panels should suffice for an average Indian home. This solar plant can comfortably power a refrigerator, TV, laptop, and three to four fans and lighting for the entire house. However, your requirement will increase if you wish to include AC, mixer grinders, water heaters, and other power-guzzling equipment. You can use our calculation formula to determine your requirements accordingly.
It depends on your power consumption, the space available on your rooftop, and your budget. We have discussed an example of a 2000 sq ft house with moderate power consumption. Consumers can use the same formulas to calculate their specific requirements.
We have described the entire calculation procedure in detail. As a result, consumers can follow the guidelines and calculate their solar panel requirements comfortably.
Generally, a one kw solar panel system should suffice for an average Indian home. However, the requirements vary according to power consumption. If your power consumption is high, your requirement for solar panels is high.
A four kw solar panel system should be ideal for a 4-bedroom house. However, much depends on the actual power consumption by the household. Our calculation procedure can help consumers calculate their precise requirements. A four kw solar panel system generally has 12 solar panels.
A four-kw solar rooftop system is perfect for a house with two air conditioners.
It depends on your average power consumption. Our calculator can prove helpful in determining the solar power plant capacity required for your home.
Yes. One kw solar power plant should be sufficient to meet minor requirements. However, this power plant is not recommended for running ACs. You will need a minimum of a three kw solar power plant to run one AC in your home.
Solar power plants generate direct current from the sunlight falling on the panels. This current is fed into a solar inverter to convert into an AC for domestic consumption. The AC generated can power your home appliances. In addition, any surplus current can be connected to the primary electrical grid.
Yes. The net metering system enables you to sell surplus electricity generated by the solar power system to the primary grid. As a result, you get reduced electricity bills.
Source: solarrooftop.gov.in, scroll.in, nytimes.com
