How many solar panels are needed for a 3kW system?

It depends on the wattage of the panels. If you use modern 540W or 550W Mono PARC panels, you only need about 6 panels. If you use older 330W Poly panels, you would need about 9-10 panels.

How much roof area is required for 1kW solar?

As a rule of thumb, you need approximately 100 square feet (10 sq meters) of shadow-free roof area for every 1 kW of solar capacity. This includes space for the panels and maintenance walkways.

Which panel wattage should I choose?

We recommend choosing high-wattage panels (500W+) as they are more efficient and require fewer mounting structures, reducing the overall balance of system (BOS) cost.

Does panel orientation matter?

Yes. In India, panels should ideally face SOUTH to capture maximum sunlight throughout the day. The tilt angle is usually equal to your city's latitude (e.g., 19 degrees for Mumbai).

Solar Panel Requirement Calculator India (2026)

Calculating Your Roof's Solar Potential

One of the biggest constraints for urban homeowners in India is roof space. Understanding how many panels can fit on your terrace is the first step in system design. This calculator helps you convert your electrical requirement (bill or kW) into physical panel count and area.

The Evolution of Panel Size & Efficiency

Solar technology has moved fast. Just 5 years ago, the standard panel was a 330W Polycrystalline module. Today, the standard is 550W Mono PERC, and the premium option is 580W+ TopCon Bifacial technology.

Why High-Wattage Panels are Better:

Less Space: A 3kW system needs ~9 Poly panels but only ~6 Mono PERC panels.
Lower BOS Cost: Fewer panels mean fewer clamps, rails, and civil work for the structure.
Better Aesthetics: Modern black panels look sleeker on your home.

Rule of Thumb: Space Calculation

While expert installers do a detailed Shadow Analysis using software like SketchUp or Helioscope, you can use a simple rule of thumb for estimation:

1 Kilowatt (kW) = 100 Sq. Ft. (approx)

This includes:

Module Area: A standard 550W panel is approx 2.2 meters x 1.1 meters (~25 sq ft).
Spacing: You cannot place panels edge-to-edge everywhere. You need gaps for thermal expansion and maintenance (cleaning walkways).

Shadow-Free Area is Key

The calculation assumes Shadow-Free area. Even a small shadow from a water tank, staircase mumty, or neighbor's building can ruin the generation of an entire string of panels.

If you have partial shadows, consider using Micro-inverters (Enphase) or Power Optimizers (SolarEdge), which allow each panel to work independently.

Frequently Asked Questions

1. Can I mix different wattage panels?

It is generally NOT recommended to mix different wattages (e.g., mixing old 330W with new 550W) in the same string as it causes mismatch losses. The entire string will perform at the level of the lowest panel.

2. What is the weight of these panels?

A standard residential solar panel weighs between 20 kg to 28 kg. A typical RCC roof in India can easily support this dead load without any structural reinforcement.

3. Can I install panels on a tin shed?

Yes, tin sheds are excellent for solar as they usually provide an elevated, shadow-free platform. Special "Short Rail" fixtures are used to clamp panels directly to the shed ribs without drilling holes (penetration-free).

Conclusion

Use this calculator to get a preliminary idea of the BOM (Bill of Materials) for your solar project. Knowing the number of panels helps you verify the quote provided by your solar installer.

Solar Panel Calculator - Check Requirement

Efficiency Tip

Plan your Roof Layout 🏠