Introduction
So you’re living in a 3BHK home and thinking about switching to solar? Good call! With rising electricity prices and falling solar panel costs, there’s never been a better time to make the switch in India.
But how many solar panels do you actually need to run your 3BHK house? Let’s break it down in simple terms.
Estimating Your Power Consumption
Before we start throwing numbers around, we need to know one thing: how much electricity do you use?
Here’s a rough estimate for a typical 3BHK household:
| Appliance | Daily Usage (kWh) |
|---|---|
| Lights & Fans (10-12) | 3–4 kWh |
| Fridge | 1–2 kWh |
| AC (1–2 units) | 4–6 kWh |
| Washing Machine | 0.5–1 kWh |
| Water Heater/Geyser | 1–2 kWh |
| TV, Computers, Others | 1–2 kWh |
📦 Total Daily Usage: 10 – 15 kWh
🗓 Monthly Usage: 300 – 450 units (kWh)
Electricity Consumption Breakdown
Let’s assume your monthly bill is for 500 units (kWh). That would be a medium to heavy usage household.
This would include:
- 2 ACs
- A fridge, geysers, washing machine
- LED lights and 3–4 fans in each room
- Regular gadget charging and TV usage
Understanding Solar Panel Capacity
Most solar panels available in India today range between 330W and 550W per panel.
➡ For example, a 400W panel generates about 1.6 kWh/day under optimal conditions (assuming 4 sun hours/day in India).
So, to generate 15 kWh/day (for a 3BHK), you’d need:
👉 15 ÷ 1.6 ≈ 10 panels of 400W capacity
How to Calculate the Number of Panels
Formula:
Total Energy Required per Day (kWh) ÷ Average Daily Output per Panel (kWh) = Number of Panels
If your home needs 15 kWh/day, and a panel gives 1.6 kWh/day, then:
15 ÷ 1.6 = 9.4 panels, round up to 10 panels
Factors That Affect Panel Count
- Location: Cities like Jaipur, Ahmedabad, Hyderabad get more sun than places like Shillong or Delhi in winter.
- Panel Efficiency: Higher-efficiency monocrystalline panels need fewer units.
- Roof Space: Panels need about 10 sq. ft. each, so 10 panels = 100 sq. ft.
- Tilt and Orientation: South-facing roofs are ideal.
Example Configurations for 3BHK Homes
✅ Low Power Use (300 units/month)
- System Size: 2.5 kW
- Panels Needed: 6–7 (400W each)
- Monthly Savings: ₹2,000+
✅ Medium Use (500 units/month)
- System Size: 4 kW
- Panels Needed: 10 (400W each)
- Monthly Savings: ₹3,500+
✅ Heavy Use (800+ units/month)
- System Size: 6 kW
- Panels Needed: 14–15
- Monthly Savings: ₹6,000+
How Much Rooftop Space Do You Need?
- Each 400W panel takes up 10–12 sq. ft.
- 10 panels = 100–120 sq. ft.
- For a 3BHK, make sure your terrace has clear, shadow-free space of at least 120–150 sq. ft.
On-Grid or Off-Grid for 3BHK Homes?
- On-Grid System is best for cities with stable power supply. You can use net metering to sell excess power.
- Off-Grid System is ideal for areas with frequent power cuts but needs battery backup, increasing the cost.
Cost Estimation for a 3BHK Solar Setup
| System Size | Approx. Cost (₹) | After Subsidy (₹)* |
|---|---|---|
| 3 kW | ₹1.5L – ₹2L | ₹90,000 – ₹1.2L |
| 4 kW | ₹2L – ₹2.6L | ₹1.2L – ₹1.6L |
| 5 kW | ₹2.5L – ₹3.2L | ₹1.5L – ₹2L |
*Assuming 20–40% MNRE subsidy for residential rooftops
Maintenance and Payback Period
- Cleaning: 1–2 times/month
- Inverter Replacement: Every 8–10 years
- Panel Life: 25+ years
- Payback Time: 4–6 years
- Lifetime Savings: ₹10L – ₹15L for a 3BHK home
Final Thoughts
If you live in a 3BHK home and want to reduce your electricity bills or go green, a 3–5kW solar system with 8–12 panels is ideal. It’s efficient, cost-effective, and pays for itself in just a few years.
Just make sure to:
- Get a professional site assessment
- Check your state subsidy
- Choose a trusted solar brand
FAQs
1. Can I run AC and fridge on solar power in a 3BHK?
Yes, a 4–5kW system can easily power ACs, fridge, and other appliances.
2. How much does a 4kW solar system cost in India?
Around ₹2 – ₹2.6 Lakhs (₹1.2L – ₹1.6L after subsidy).
3. Will I still get electricity from the grid?
Yes, if you’re using an on-grid system with net metering.
4. How much roof area is needed for a 5kW system?
Approximately 120–150 sq. ft. of shadow-free space.
5. Can I add more panels later?
Yes, modular setups let you scale up as needed.
