Emit Solar | Home Solar Panels | Easy Ownership
In Malaysia, solar is mainly about savings – so it is tempting to install the biggest system your roof can fit. But bigger is not always better.
Past a certain point, extra panels can add more cost than savings. The goal is to find your “Goldilocks” size – not too big, not too small but just right.
Here’s how to find it.
A quick rule of thumb
Solar systems are measured in kWp (kilowatt-peak) – that’s the size. In Malaysia, a simple estimate is:
1kWp ≈ 100kWh per month (over a year)
So:
- A 5 kWp system makes about 500kWh a month
- An 8kWp system about 800kWh a month
To size yours, compare that to the kWh usage on your TNB bill – not the Ringgit total.
Your bill amount can change because of tariffs, taxes, rebates and surcharges. Your kWh usage shows how much electricity your home actually consumes.
From there, three things decide your number.
What your roof allows
This is the hard limit. A bigger roof can fit more panels, and each kWp usually needs about 5m² of space. But the total roof area is not the same as solar usable area. A few things affect how much space can actually be used:
Panels cannot be installed to the edge.
Clear margins are needed for maintenance access and fire-safety – packing them edge-to-edge isn’t allowed, or wise.
Roofs come in sections.
Most roofs split into several faces, often at angles, and each is planned separately.
Panels are rectangular.
They cannot fill every corner of an angled section, so some space is always lost to the layout.
Some areas may be shaded or unsuitable.
Water tanks, walls, trees, neighbouring houses, and roof structures can reduce usable space.
So we do not size a system based on raw roof area. We size it based on the part of your roof that can realistically and safely support the panels.
How you use electricity
Your Consumption Today
Easy part: read the monthly kWh off your TNB bill. That’s your baseline.
Your Future Consumption
A solar system lasts decades, and the universal trend is for households to use more power over time, not less. But how much your usage grows depends a lot on the home and life changes ahead – so it’s worth planning for the big ones.
For example:
|
IF YOU ADD…
|
ROUGHLY ADDS
|
|---|---|
|
An electric vehicle
|
200kWh /month
|
|
More air-conditioning
|
~100kWh per HP /month
|
|
A fish pond or pool pump
|
~100kWh /month
|
An EV makes a bigger system more worthwhile, especially if you charge it during the day. That’s when solar gives you the highest value – because power comes straight from your roof instead of the grid.
Where the money works out
Not all the kilowatt-hours your panels make are worth the same. Solar saves you two ways – and one is worth far more than the other. This is the heart of the “just right” idea.
100% Value
Solar Electricity you use directly
Use electricity while your panels are generating and you don’t use TNB supply – a saving of RM0.44/kWh, or RM0.54 on the higher tariff.
>60% Value
Solar Electricity you sell to TNB
Excess Solar Electricity you don’t use is sold to TNB for a credit – RM0.27/kWh, or RM0.37 on the higher tariff.
Why smaller can pay back faster
Here’s the part that surprises people. Say you use 1,000kWh a month, and about 30% of it in daytime. That means you use about 300 kWh during solar hours. That daytime usage is fixed by your habits – it doesn’t increase just because you install more panels.
10kWp
generates ~1,000kWh/month
Used directly (best value): ~300kWh
Sold to TNB (lower value): ~700kWh
Share at best value: 30%
MORE PANELS, MORE COST
7kWp
generates ~700kWh/month
Used directly (best value): ~300kWh
Sold to TNB (lower value): ~400kWh
Share at best value: 43%
LESS COST, OFTEN FASTER PAYBACK
Same daytime savings, less to spend – so the smaller system can pay for itself sooner. The trick is not going too small either: you still want enough panels to cover your daytime use across the morning and evening, not just at midday.
That balance point is your “Goldilocks” size.
Three ways to size – which one’s you?
OPTION A
Maximise your roof
Fit as many panels as the roof safely allows
The most generation. Best if you’re planning big future loads like an EV, since the extra capacity is there waiting.
If your current usage is much lower than your system’s generation, payback may take longer because more energy is exported at a lower value.
OPTION B
Maximise savings
Size to match your usage.
This captures the most savings Solar ATAP allows, without generating more than your home can benefit from.
This option usually gives the best total savings but it may not always give the fastest payback.
OPTION C
Maximise your payback
Fits your daytime consumption.
Smaller solar system means less to spend on the system and a higher share of your Solar Electricity is used directly at the best value.
This option may not produce the highest total savings, but it often gives the fastest return.
Going too small may limit your savings. Going too big may leave you exporting too much at a lower value. That’s why, for most homes, the sweet spot sits between biggest savings and best payback – the “Goldilocks” zone. We’ll show you the numbers for each so the choice is yours.
THE 1,500 kWh LINE
Honestly? We wanted to see whether this mechanism could give our customers something beyond savings.
TNB charges a higher rate once your monthly usage passes 1,500kWh – and it applies to your whole bill, not just the part above the line.
- RM0.54 above 1,500kWh
- RM0.44 below 1,500kWh
If your usage sits just above 1,500kWh, a well-sized system can help you use enough solar electricity directly during the day and reduce what you draw from TNB. That can pull you under the line and shift your whole bill to the lower rate. That’s a real, repeating saving on top of everything else, and it’s one good reason to lean a little larger: enough to cover your daytime use and stay comfortably under the line as your usage grows.
AFA can also affect your bill
You’ll spot AFA on your bill – a fuel-cost adjustment that changes every month. Some months it’s a small extra charge; some months it’s a rebate in your favour. It works a little like the 1,500kWh line: there’s a level (around 600kWh a month) below which it doesn’t apply, and when it does, it affects the whole bill.
You’ll spot AFA on your bill – a fuel-cost adjustment that changes every month. Some months it’s a small extra charge; some months it’s a rebate in your favour. It works a little like the 1,500kWh line: there’s a level (around 600kWh a month) below which it doesn’t apply, and when it does, it affects the whole bill.
Buy for the future, not just today
Electricity only gets more expensive. The RM300 bill you’re trying to trim today could be a RM500 bill in a few years on exactly the same usage, as tariffs climb. So the real question isn’t only what solar saves you this month – it’s what your bill, and your consumption, will look like down the road.
That’s why we don’t lean too hard on today’s savings. Size for where your usage is heading, and a system that looks a touch generous now turns out just right tomorrow.
And unlike almost anything else you’ll buy for your home, solar doesn’t just cost you – over its life, it’s probably the only thing in the house that puts real money back in your pocket.
Let’s find your Goldilocks size
Share a few details with us and we’ll be in touch to assess your home properly.
We’ll look at your roof, ask for your recent TNB bill, understand your daytime usage, and recommend a solar system size that’s just right for you.
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