Solar Panels: You have two geysers at home—how many solar panels do you need?

Solar Panels: Having two geysers at home—often used for hot water in the bathroom and kitchen—can lead to a hefty electricity bill. If you are considering installing solar panels on your roof to avoid these high costs, it is essential to understand the calculations first.

Solar Panels: Many households need hot water in both the bathroom and the kitchen, often leading to two separate geysers. However, when both are switched on, there is a significant surge in electricity consumption, resulting in a very high monthly electricity bill. To avoid this, many people are now installing rooftop solar power systems.

The biggest question, however, is: if a home has two geysers—whether used simultaneously or at different times—what capacity (in kilowatts) should the solar system be? Without the correct capacity, the system could either become overloaded or fail to provide sufficient power. Let’s look at what kind of solar setup and wiring you would need to support two geysers.

How much power capacity is needed for two geysers?

Before calculating the requirements, it is crucial to determine the total power load in your home. Typically, Indian households use 15 to 25-liter storage geysers, which have a capacity of approximately 2,000 watts (2 kW). Additionally, a smaller geyser used in the kitchen or elsewhere usually consumes between 1,500 and 2,000 watts.

This means that if you turn on both geysers at the same time, they alone will draw a substantial load of 3.5 to 4 kilowatts (3,500 to 4,000 watts). Besides water heaters, a home typically has other appliances like lights, fans, and Wi-Fi routers. Therefore, the energy demand extends beyond just the water heaters to the rest of the household.

Which solar system should you choose?

If you want to power two water heaters using solar energy, a 5 kW solar system would be the most suitable choice for your home. Modern monocrystalline PERC and bifacial solar panels—with capacities ranging from 540W to 550W—are widely available in the market. To set up a 5 kW system, you would need approximately 9 to 10 such panels installed on your roof.

For these 9 to 10 panels, you will need about 450 to 500 square feet of open space on your roof that receives direct, unshaded sunlight throughout the day. This system generates an average of 20 to 25 units of electricity per day. With this amount of power, your two water heaters can easily run for one to two hours a day, while also covering the energy requirements of other essential household appliances.

Which system should you select?

When choosing a solar system for two water heaters, it is important to consider the type of inverter and the overall system configuration. If your area experiences infrequent power cuts, an on-grid solar system is the ideal choice. There is no hassle regarding batteries, and any excess electricity generated during the day is fed directly into the grid, which significantly lowers your electricity bill. You can also avail of a good subsidy under the government’s 'Surya Grih' (Solar Home) scheme.

If you live in an area where power consumption is high and you wish to run your electrical appliances entirely on solar power, an off-grid system would be the right choice. However, this requires batteries, which can substantially increase the initial cost. Therefore, make your decision only after carefully considering your budget and your specific electricity requirements.