How to Calculate the Right Solar System Size for Your Home:
✅ Step 1: Check Your Monthly Electricity Usage
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Mention how to check from electricity bills (average kWh/month).
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Example: If your average monthly consumption is 300 units (kWh), note it down.
✅ Step 2: Understand Solar Generation in Your Region
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India gets an average of 4-6 hours of effective sunlight/day.
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Add a solar generation factor chart for major Indian cities:
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Lucknow: 4.5 kWh/kW/day
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Delhi: 4.6 kWh/kW/day
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Mumbai: 4.2 kWh/kW/day
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Hyderabad: 5.0 kWh/kW/day
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✅ Step 3: Use This Formula
Where:
Monthly Solar Generation per kW = Generation Factor (kWh/day)×30
Example:
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Consumption = 300 units/month
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Location = Lucknow (4.5 kWh/day)
Monthly Solar Generation per kW=4.5×30=135 units
Required System Size= 300/135 = 2.22kw
So, recommend a 2.5 kW solar system.
Step 4: Check Roof Space Availability
Before finalizing your solar system size, it’s important to ensure your rooftop has enough usable area. As a general rule:
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Each 1 kW solar system requires about 100 sq. ft. of shadow-free rooftop space.
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Panels should ideally face south for maximum electricity generation in India.
Here’s a simple reference table to estimate the roof space you’ll need:
| System Size (kW) | Approx. Roof Area (sq. ft.) |
|---|---|
| 1 kW | 100 |
| 2 kW | 200 |
| 3 kW | 300 |
| 5 kW | 500 |
| 10 kW | 1000 |
Step 5: Choose the Right Solar System Type
In India, there are three main types of rooftop solar systems you can install for your home. The best option depends on your area’s net metering policy, power cut frequency, and backup needs.
Types of Solar Systems:
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On-Grid Solar System:
Connected to the main electricity grid. Surplus solar power is exported to the grid using net metering, reducing your electricity bill. This is ideal for homes in cities and towns where power cuts are rare. -
Off-Grid Solar System:
Operates independently of the main grid with battery storage. It’s suitable for remote areas without reliable electricity or where frequent power cuts happen. -
Hybrid Solar System:
A combination of both — connected to the grid with battery backup. This system supplies power to your home, exports excess energy to the grid, and keeps backup batteries charged for emergencies.
Our Recommendation:
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If net metering is available and you rarely face power cuts, go for an On-Grid system.
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If your area faces frequent outages, consider a Hybrid system.
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If there’s no grid connection or heavy power disruption, opt for an Off-Grid system.
🔸 Bonus: Estimate Your Monthly Savings
Installing a solar system significantly lowers your electricity expenses. Here’s an approximate savings estimate based on system size:
| System Size (kW) | Approx. Monthly Savings (₹) |
|---|---|
| 1 kW | ₹1,000–₹1,200 |
| 2 kW | ₹2,000–₹2,400 |
| 3 kW | ₹3,000–₹3,600 |
| 5 kW | ₹5,000–₹6,000 |
| 10 kW | ₹10,000–₹12,000 |
Note: Actual savings depend on your electricity tariff, daily sunlight hours, and the system’s performance in your location.
🔸 Conclusion
Choosing the right solar system size is essential for maximizing your savings, ensuring proper system efficiency, and getting the best returns on your investment. By accurately assessing your power consumption, checking your rooftop space, selecting the appropriate system type, and estimating your savings — you can make an informed, confident decision.
Want professional guidance?
Reach out to our solar experts today for a free consultation or site survey. Let us help you design the perfect solar solution for your home.
