How many solar panels do I need to run a typical 3-BHK house in Bangalore?
TL;DR: A typical 3-BHK household in Bangalore uses around 300-600 kWh/month - that usually needs a 3-6 kW solar system (about 10-18 panels using modern 350W modules). For small businesses, we show a 10 kW example and roof needs.
Quick answer
Panel count depends on your monthly electricity consumption and panel wattage:
| Usage Type | Monthly Consumption (kWh) | System Size Needed | Panel Count (350W panels) |
|---|---|---|---|
| Light Usage 3-BHK | 250-350 kWh | 3-4 kW | 9-12 panels |
| Average 3-BHK | 400-500 kWh | 5 kW | 14-15 panels |
| High Usage 3-BHK (AC/EV) | 600-800 kWh | 6-8 kW | 17-23 panels |
| Small Business / Shop | 800-1,200 kWh | 10 kW | 28-30 panels |
💡 Pro tip: Check your last 3 months of electricity bills and calculate your average monthly consumption. That's the best starting point for sizing your system.
How we calculate panel count (simple formula & example)
Here's the step-by-step process we use to size your system:
Calculate daily consumption from monthly bills
Example: 450 kWh/month ÷ 30 days = 15 kWh/day
Calculate system size needed (kW)
Daily consumption ÷ peak sun hours ÷ system efficiency
15 kWh ÷ 5 peak sun hours ÷ 0.75 efficiency = 4 kW
(We use 5 peak sun hours for Bangalore and 75% system efficiency to account for inverter/wiring losses)
Calculate panel count
System size (watts) ÷ panel wattage = number of panels
4,000W ÷ 350W per panel = 11.4 → 12 panels
(Always round up to the nearest whole number)
Estimate roof space needed
Panel dimensions: ~2m × 1m = 2 sq meters (~21.5 sq ft) per panel
12 panels × 21.5 sq ft = ~260 sq ft roof space
(Add 20-30% extra for spacing, walkways, and mounting structure)
✅ Result for this example: A 4 kW system with 12 panels (350W each) requiring approximately 260-340 sq ft of usable roof space.
Example: typical 3-BHK scenarios (low / average / high usage)
Here's how different usage patterns affect panel count and cost:
Scenario A: Light Usage 3-BHK (No AC, minimal appliances)
Monthly consumption: 250-350 kWh
Typical appliances: LED lights, fans, fridge, TV, laptop/router, washing machine (occasional use)
System Size
3-4 kW
Panel Count (350W)
9-12 panels
Roof Space Required
~250-300 sq ft
Typical Cost Range
₹1.5-2.5 lakh
Scenario B: Average 3-BHK (1 AC, normal appliances)
Monthly consumption: 400-500 kWh
Typical appliances: All basics + 1 AC (used 4-6 hours/day), water heater, microwave, induction cooktop
System Size
5 kW
Panel Count (350W)
14-15 panels
Roof Space Required
~350-400 sq ft
Typical Cost Range
₹2.5-3.5 lakh
⭐ Most Popular: This is the most common system size for Bangalore 3-BHK apartments and villas.
Scenario C: High Usage 3-BHK (Multiple ACs, EV charging)
Monthly consumption: 600-800 kWh
Typical appliances: All basics + 2-3 ACs (heavy use), electric vehicle charging, water purifier, dishwasher, high power appliances
System Size
6-8 kW
Panel Count (350W)
17-23 panels
Roof Space Required
~450-600 sq ft
Typical Cost Range
₹3.5-5.5 lakh
Note: Costs shown are approximate on-grid system costs without battery backup. Add ₹1.1-1.8 lakh for a 6 kWh battery if you want night backup.
10 kW system overview (panel count, roof area, typical use-cases)
A 10 kW system is typically used for large homes, independent villas, or small commercial establishments like shops, clinics, or offices.
10 kW System Specifications
Panel Count
28-30 panels
(using 350W panels)
With 400W panels: 25 panels | With 300W panels: 33-34 panels
Roof Space Required
~700-800 sq ft
(usable, unshaded area)
Equivalent to approximately 65-75 sq meters
Daily Production (avg)
~35-40 kWh/day
(assuming 5 peak sun hours)
Annual: ~13,000-14,500 kWh
Typical Cost Range
₹5.5-7.5 lakh
(on-grid, no battery)
Add ₹2-4 lakh for battery backup (depends on capacity)
Typical Use Cases:
Large Independent Villas
4+ BHK with multiple ACs, pool pumps, EV charging
Small Retail Shops
Showrooms, grocery stores with refrigeration
Small Clinics / Offices
Medical clinics, dental offices, IT startups
Small Restaurants / Cafes
With AC and kitchen equipment (partial offset)
💼 Commercial benefit: 10 kW systems can offset 800-1,200 kWh/month, potentially saving ₹6,000-10,000/month on commercial electricity rates. ROI typically 5-7 years.
Roof and shading considerations for Bangalore homes
📐Usable roof area vs total area
Not all roof space is usable. Subtract areas with water tanks, chimneys, AC outdoor units, solar water heaters, and shaded sections. Typically, 60-70% of total roof area is usable for panels.
🌳Shading from trees and buildings
Even partial shading can significantly reduce output. We use satellite imagery and site visits to identify shading patterns throughout the day/year. In Bangalore, south-facing roofs with minimal shading are ideal.
🏗️Roof type and structure
RCC flat roofs (common in Bangalore apartments) are ideal - easy to install and maintain. Sloped tile roofs need specialized mounting. We assess structural load capacity before installation (~15 kg/sq meter for typical systems).
🧭Orientation and tilt
South-facing panels produce the most energy in Bangalore (latitude ~13°N). We install at 10-15° tilt for optimal annual production. East-west orientations also work but may reduce output by 10-15%.
🔍Apartment rooftop considerations
For apartments, check if your society allows individual solar installations or requires rooftop-sharing arrangements. Some societies offer collective rooftop solar with allocated capacity per flat. We help navigate society approvals.
📸 Free Roof Assessment: We provide a detailed 3D roof layout showing exact panel placement, shading analysis, and production estimates before you commit.
Get started on your Solar journey today.
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