How much roof area do I need for a 5kW rooftop solar system?

If you’re planning a 5kW rooftop solar system, the real question isn’t just “how big is my roof?”—it’s how much shadow-free, usable area you have after leaving space for access, tilt, and obstacles.

Quick answer (rule-of-thumb)

For most Indian homes, plan 350 to 600 sq ft of shadow-free roof area for a 5kW system.

• Compact / modern panels + tight layout: ~350–450 sq ft
• Conservative planning (easy access + tilt spacing): ~500–650 sq ft

Government/discom FAQs commonly cite ~10–12 sq. m per 1 kW (≈ 100–120 sq ft per 1 kW) as a planning thumb rule, which translates to ~50–60 sq. m (540–650 sq ft) for 5kW.

Why the range is so wide

A 5kW system’s panel “footprint” can be surprisingly small, but the usable roof area required grows because of:

• Row spacing (to avoid panels shading each other if tilted)
• Walkway/service clearance (future cleaning, waterproofing, antenna/water tank access)
• Parapet walls and obstacles (overhead tanks, stair headroom, solar water heater, pipes)
• Tilt angle choice (higher tilt usually needs more spacing)
• Mounting style (flush/low-tilt vs elevated structure)

Panel footprint vs usable roof area (what installers actually design for)

1) Panel footprint (just the panels)

Modern high-watt panels are physically large. For example, a common ~540–550W class module is roughly 2278 × 1134 mm (about 2.58 m² per panel).

A typical 5kW setup might use:

• 10 panels × 550W ≈ 5.5kW DC (often “5kW” inverter pairing depends on design)
• Panel footprint ≈ 10 × 2.58 = ~25.8 m² (≈ 278 sq ft) before spacing

2) Usable roof area (what you should plan for)

Once you add gaps, structure, and access:

• Low-tilt / compact layouts: ~30–40 m² (≈ 323–430 sq ft)
• Higher tilt + comfortable walkway: ~45–60 m² (≈ 485–650 sq ft) — matches the conservative 10–12 m² per kW guideline.

Roof area estimate table for a 5kW system

These are practical planning ranges (shadow-free usable area):

Mounting / layout style	Typical usable area for 5kW
Very compact (low tilt, tight rows)	350–450 sq ft
Standard residential (tilt + basic access)	450–600 sq ft
Conservative (more spacing + wide walkway)	550–650 sq ft

 

How to estimate your roof area in 5 minutes (without fancy tools)

Step 1: Calculate total terrace area

Measure length × width (in feet).

Example: 30 ft × 20 ft = 600 sq ft

Step 2: Remove “not usable” zones

Subtract space for:

• Water tank + plumbing zone
• Stair headroom
• Solar water heater (if present)
• Satellite dish/antenna
• Parapet shadow zones (especially in winter mornings/evenings)

Step 3: Check for shadows

If any part gets shadow from:

• Neighbor’s building
• Trees
• Overhead cables
• Lift room / mumty

Treat that area as not usable, especially during 9am–3pm.

What matters more than roof size

Shadow-free area (non-negotiable)

Even partial shading can reduce output significantly, so clear sunlight is key.

Orientation & tilt

• South-facing (typical) gives best annual yield for most of India
• East-West layouts can be more compact on space (often used when roof is tight), with a small generation trade-off

Roof strength & waterproofing

Panels last 25+ years—so ensure:

• waterproofing is done before installation if required
• structure is strong enough for mounting loads

A useful tool to sanity-check your plan

The National Portal for Rooftop Solar (MNRE) has a calculator that takes available rooftop area as an input and suggests a capacity (indicative).

FAQ (quick)

1. Can I fit 5kW on a 500 sq ft roof?
• Often yes, if most of it is shadow-free and you use a compact layout. If you have many obstacles or need wide spacing, it can get tight.
2. If I have only ~350 sq ft, is 5kW still possible?
• Sometimes—using higher watt panels and compact mounting. But shading and access clearance become critical.
3. Does inverter type change roof area?
• Not much. Roof area is mainly about panel count, layout, and spacing, not the inverter.