The average Malaysian terrace house needs 8-12 solar panels (4-6 kW system) based on roof area (30-50 sqm) and monthly electricity bills (RM 300-600). This comprehensive guide helps you calculate the exact number of solar panels your specific terrace house requires, accounting for roof type, consumption patterns, and shading.
Quick Answer: Solar Panel Count by Terrace House Type
| Terrace Type | Roof Area | System Size | Number of Panels (550W) | Monthly Bill |
|---|---|---|---|---|
| Single Storey | 25-35 sqm | 3-4 kW | 6-8 panels | RM 200-350 |
| Double Storey (Intermediate) | 30-45 sqm | 4-5 kW | 8-10 panels | RM 350-500 |
| Double Storey (End Lot/Corner) | 50-70 sqm | 6-8 kW | 12-15 panels | RM 500-800 |
| 3-Storey Terrace | 30-45 sqm | 4-6 kW | 8-12 panels | RM 400-700 |
Important: This assumes 550W panels (standard in 2026). If your installer uses 450W panels, multiply panel count by 1.22. For 600W panels, multiply by 0.92.
Step-by-Step: How to Calculate Solar Panels for Your Terrace House
Step 1: Determine Your Monthly Electricity Consumption
Check your TNB bill for "Current Month Consumption" (in kWh). Average last 6 months for accurate sizing.
Example TNB Bill:
- January: 620 kWh
- February: 580 kWh
- March: 640 kWh
- April: 590 kWh
- May: 610 kWh
- June: 600 kWh
- Average: 607 kWh/month
Step 2: Calculate Required System Size (kW)
Formula: System Size (kW) = Monthly kWh ÷ 120
The "120" factor accounts for:
- 30 days/month
- 4 peak sun hours/day (Malaysia average)
- 80% system efficiency (inverter loss, wiring loss, temperature derating)
Example: 607 kWh ÷ 120 = 5.06 kW → Round up to 5 kW system
Step 3: Convert kW to Number of Panels
Formula: Number of Panels = System Size (kW) × 1,000 ÷ Panel Wattage
Example: 5 kW × 1,000 ÷ 550W = 9.09 → 10 panels (always round up)
Step 4: Verify Roof Area Sufficiency
Each 550W panel needs ~2.8 sqm (including spacing for access and shading avoidance).
Formula: Required Roof Area = Number of Panels × 2.8 sqm
Example: 10 panels × 2.8 sqm = 28 sqm minimum
If your roof is smaller, reduce system size or use higher-wattage panels (600W = 2.6 sqm/panel).
Detailed Sizing by Terrace House Type
1. Single Storey Terrace (22' × 75' or 20' × 70')
Typical Characteristics:
- Built-up Area: 1,000-1,200 sqft
- Roof Area: 25-35 sqm (after accounting for hips, vents, water tanks)
- Occupants: 2-4 people
- Monthly Bill: RM 200-350 (350-600 kWh)
Recommended System:
- System Size: 3-4 kW
- Number of Panels: 6-8 panels (550W each)
- Cost: RM 11,500-15,500
- Monthly Savings: RM 220-280
- Payback Period: 4.5-5.5 years (including Solar ATAP export bill credits)
Layout Example (8 panels = 4 kW):
- 2 rows × 4 panels (portrait orientation)
- Total dimensions: 4.4m (width) × 7.0m (length) = 30.8 sqm
- Fits on: Single-storey terrace with gable roof (one plane available)
2. Double Storey Intermediate Terrace (22' × 75')
Typical Characteristics:
- Built-up Area: 1,600-2,200 sqft
- Roof Area: 30-45 sqm
- Occupants: 4-6 people
- Monthly Bill: RM 350-500 (600-850 kWh)
Recommended System:
- System Size: 4-5 kW
- Number of Panels: 8-10 panels
- Cost: RM 15,500-21,000
- Monthly Savings: RM 280-420
- Payback Period: 2.5-2.8 years (with ATAP)
Layout Example (10 panels = 5 kW):
- 2 rows × 5 panels OR 2 planes (5 panels each)
- Total dimensions: 5.5m × 7.0m = 38.5 sqm
- Fits on: Hip roof (2 planes) or gable roof (1 plane)
3. Double Storey Corner/End Lot (24' × 80' or wider)
Typical Characteristics:
- Built-up Area: 2,400-3,200 sqft
- Roof Area: 50-70 sqm (more planes available)
- Occupants: 5-8 people
- Monthly Bill: RM 500-800 (850-1,400 kWh)
Recommended System:
- System Size: 6-8 kW
- Number of Panels: 12-15 panels
- Cost: RM 22,000-30,000
- Monthly Savings: RM 480-700
- Payback Period: 2.3-2.6 years (with ATAP)
Layout Example (15 panels = 8 kW):
- 3 planes: Front (5 panels), Back (5 panels), Side (5 panels)
- Total dimensions: 15 panels × 2.8 sqm = 42 sqm (spread across 3 planes)
- Fits on: Corner lot with 3 roof planes available
4. 3-Storey Terrace (20' × 70' or 22' × 75')
Typical Characteristics:
- Built-up Area: 2,000-3,000 sqft
- Roof Area: 30-45 sqm (but smaller footprint due to height)
- Occupants: 4-7 people
- Monthly Bill: RM 400-700 (700-1,200 kWh)
Recommended System:
- System Size: 4-6 kW
- Number of Panels: 8-12 panels
- Cost: RM 15,500-24,000
- Monthly Savings: RM 280-500
- Payback Period: 2.6-3.0 years (with ATAP)
Layout Challenges:
- Roof area is SMALLER than 2-storey (narrower footprint)
- Scaffolding required (RM 800-2,000 extra cost)
- Steep roof pitch (>30°) may require additional mounting bracing
How TNB Bill Amount Determines Solar Panel Count
Quick sizing by monthly TNB bill (rule of thumb):
| Monthly Bill (RM) | Consumption (kWh) | System Size (kW) | Number of Panels (550W) | Roof Area Needed |
|---|---|---|---|---|
| RM 150-250 | 300-450 kWh | 2.5-3.5 kW | 5-7 panels | 14-20 sqm |
| RM 250-350 | 450-600 kWh | 3.5-5 kW | 7-10 panels | 20-28 sqm |
| RM 350-500 | 600-850 kWh | 5-7 kW | 10-13 panels | 28-36 sqm |
| RM 500-700 | 850-1,200 kWh | 7-10 kW | 13-19 panels | 36-53 sqm |
| RM 700-1,000 | 1,200-1,700 kWh | 10-14 kW | 19-26 panels | 53-73 sqm |
Pro Tip: Size for 80-90% of your consumption, not 100%. Oversizing wastes roof space and capital (excess export credits at RM 0.218/kWh are lower than avoided consumption at RM 0.516-0.571/kWh).
FAQ: Solar Panels for Terrace Houses Malaysia
How many solar panels for a terrace house in Malaysia?
8-12 panels (4-6 kW) for typical double-storey intermediate terrace (RM 350-600 monthly bill). Single-storey: 6-8 panels (3-4 kW). Corner lot: 12-15 panels (6-8 kW). Use formula: (Monthly kWh ÷ 120) × 1,000 ÷ 550W = number of panels.
Can I fit solar panels on a small terrace house?
Yes, if you have >20 sqm usable roof area. A 3 kW system (6 panels) needs ~17 sqm. Even small terrace houses (20' × 60') typically have 25-30 sqm available. Use higher-wattage panels (600W) if space is tight.
What if my terrace house roof is too small for my electricity needs?
Size solar for 70-80% of consumption, not 100%. For example, if you need 10 kW but only have space for 6 kW, install 6 kW. You'll still save RM 480/month (vs RM 0 without solar). Alternatively, reduce consumption (LED bulbs, efficient AC) before sizing solar.
Do I need permission from my terrace house neighbor to install solar?
No, if panels are on YOUR roof within YOUR property boundary. However, if panels overhang neighbor's airspace or cast shadows on their property, you may face disputes. Keep panels >0.5m from property line to avoid issues.
Can I add more solar panels to my terrace house later?
Yes, but you'll need to re-apply for Solar ATAP (separate application). Easier and cheaper to size correctly upfront. Expansion costs 10-15% more per kW due to mobilization, permits, and second TNB commissioning. Install maximum capacity your roof can fit from Day 1.
Ready to size your solar system? Use our instant solar calculator or book the RM100 priority site visit from Trexon. We'll measure your roof, analyze shading, and design the optimal layout.