A typical Malaysian terrace house needs about 9 to 12 solar panels (5.58 to 7.44 kWp) for a monthly TNB bill of RM200 to RM500, depending on roof area (30-50 sqm) and consumption. This guide helps you calculate how many panels your terrace house needs, 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 (620W) | Monthly Bill |
|---|---|---|---|---|
| Single Storey | 25-35 sqm | 5.58 kWp | 9 panels | RM 200-300 |
| Double Storey (Intermediate) | 30-45 sqm | 6.20-7.44 kWp | 10-12 panels | RM 350-500 |
| Double Storey (End Lot/Corner) | 50-70 sqm | 7.44-11.16 kWp | 12-18 panels | RM 500-800 |
| 3-Storey Terrace | 30-45 sqm | 6.20-7.44 kWp | 10-12 panels | RM 400-500 |
Important: Trexon catalogue systems use 620W panels. There is no 4 kW, 5 kW or 10 kW package; the nearest catalogue sizes are used throughout this guide. Systems above 7.44 kWp (5 kWac inverter) need a three-phase supply.
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 the 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 System Size (kWp)
Formula: System Size (kWp) = Monthly kWh / 105
The "105" factor is 30 days a month x 3.5 peak sun-hours a day, the basis we use for catalogue generation. It is the size that would generate about 100% of your consumption; because exported power is credited at only RM0.2703/kWh (versus RM0.4443/kWh avoided when you use solar at home), you may choose a size below this.
Example: 607 kWh / 105 = 5.78 kWp, so choose the nearest catalogue size: 6.20 kWp (RM 16,999, Solis).
Step 3: Convert kWp to Number of Panels
Formula: Number of Panels = System Size (kWp) x 1,000 / Panel Wattage
Example: 6.20 kWp x 1,000 / 620W = 10 panels
Step 4: Verify Roof Area Sufficiency
Allow about 2.8 sqm per panel (including spacing for access and shading avoidance).
Formula: Required Roof Area = Number of Panels x 2.8 sqm
Example: 10 panels x 2.8 sqm = 28 sqm minimum
If your roof is smaller, reduce the system size.
Detailed Sizing by Terrace House Type
Estimate on the RP4 domestic tariff (from 1 Jul 2025), before AFA, the 1.6% RE Fund and service tax; 3.5 sun-hours a day; about 40% of solar used at home and the rest exported and credited at the 27.03 sen Energy Charge (capped at what you import) for 10 years under Solar ATAP; no tariff increases. Your bill and roof will change the figures. Prices are Solis catalogue prices (Huawei adds RM3,000, Sungrow adds RM5,000).
1. Single Storey Terrace (22' x 75' or 20' x 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 200-300 (about 556-739 kWh)
Recommended System:
- System Size: 5.58 kWp
- Number of Panels: 9 panels (620W each)
- Cost: RM 15,999
- Monthly Savings: about RM 143-184
- Payback Period: about 7.2-9.3 years (including Solar ATAP export bill credits)
Layout Example (9 panels = 5.58 kWp):
- 2 rows (5 + 4 panels), portrait orientation
- About 25 sqm of roof area
- Fits on: Single-storey terrace with gable roof (one plane available)
2. Double Storey Intermediate Terrace (22' x 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 (about 800-986 kWh)
Recommended System:
- System Size: 6.20-7.44 kWp
- Number of Panels: 10-12 panels
- Cost: RM 16,999-17,999
- Monthly Savings: about RM 207-291
- Payback Period: about 5.2-6.8 years (with ATAP)
Layout Example (10 panels = 6.20 kWp):
- 2 rows x 5 panels OR 2 planes (5 panels each)
- About 28 sqm of roof area
- Fits on: Hip roof (2 planes) or gable roof (1 plane)
3. Double Storey Corner/End Lot (24' x 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 (about 986-1,500 kWh)
Recommended System:
- System Size: 7.44-11.16 kWp
- Number of Panels: 12-18 panels
- Cost: RM 17,999-24,999
- Monthly Savings: about RM 291-418
- Payback Period: about 5.0-5.2 years (with ATAP)
Layout Example (16 panels = 9.92 kWp):
- 3 planes: Front (6 panels), Back (5 panels), Side (5 panels)
- 16 panels x 2.8 sqm = about 45 sqm (spread across 3 planes)
- Fits on: Corner lot with 3 roof planes available
4. 3-Storey Terrace (20' x 70' or 22' x 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 400-500 (about 828-986 kWh)
Recommended System:
- System Size: 6.20-7.44 kWp
- Number of Panels: 10-12 panels
- Cost: RM 16,999-17,999
- Monthly Savings: about RM 230-291
- Payback Period: about 5.2-6.2 years (with ATAP)
Layout Challenges:
- Roof area is SMALLER than 2-storey (narrower footprint)
- Scaffolding may be required (extra cost)
- Steep roof pitch (>30 degrees) may require additional mounting bracing
How TNB Bill Amount Determines Solar Panel Count
Quick sizing by monthly TNB bill (rule of thumb, RP4 tariff):
| Monthly Bill (RM) | Consumption (kWh) | System Size (kWp) | Number of Panels (620W) | Roof Area Needed | Payback (Solis) |
|---|---|---|---|---|---|
| RM 200 | about 556 kWh | 5.58 kWp | 9 panels | about 25 sqm | about 9.3 years |
| RM 300 | about 739 kWh | 5.58 kWp | 9 panels | about 25 sqm | about 7.2 years |
| RM 400 | about 828 kWh | 6.20 kWp | 10 panels | about 28 sqm | about 6.2 years |
| RM 500 | about 986 kWh | 7.44 kWp | 12 panels | about 33 sqm | about 5.2 years |
| RM 600 | about 1,163 kWh | 8.68 kWp | 14 panels | about 39 sqm | about 5.3 years |
| RM 1,000 | about 1,597 kWh | 11.78 kWp | 19 panels | about 53 sqm | about 3.6 years |
Pro Tip: Do not oversize. Excess export credit is worth only RM 0.2703/kWh against RM 0.4443/kWh (RM 0.5443 above 1,500 kWh a month) for solar you use at home, and credit that is not used up in the billing period is forfeited. Oversizing also wastes roof space and capital.
FAQ: Solar Panels for Terrace Houses Malaysia
How many solar panels for a terrace house in Malaysia?
About 9 panels (5.58 kWp) for a single-storey terrace with a RM200-300 bill, 10-12 panels (6.20-7.44 kWp) for a double-storey intermediate terrace (RM350-500 bill), and 12-18 panels (7.44-11.16 kWp) for a corner lot (RM500-800 bill). Use the formula: (Monthly kWh / 105) x 1,000 / 620W = number of panels.
Can I fit solar panels on a small terrace house?
Yes, if you have at least about 25 sqm of usable roof area. The smallest catalogue system, 5.58 kWp (9 panels), needs about 25 sqm. Even small terrace houses (20' x 60') typically have 25-30 sqm available.
What if my terrace house roof is too small for my electricity needs?
Size solar for the roof you have. For example, if your RM700 bill suggests 9.92 kWp but you only have space for 6.20 kWp, install 6.20 kWp: on a RM700 bill that still saves about RM 232 a month, compared with no saving 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 a neighbor's airspace or cast shadows on their property, you may face disputes. Keep panels more than 0.5m from the property line to avoid issues.
Can I add more solar panels to my terrace house later?
Yes, but you will need to re-apply for Solar ATAP (separate application). It is easier and cheaper to size correctly upfront, because expansion repeats mobilization, permits, and TNB commissioning. Install the capacity your roof can fit and your bill justifies from the start.
Ready to size your solar system? Use our instant solar calculator or get a free quote from Trexon. We'll review your roof photos, analyse shading, and design the layout.
