If you are planning to install solar panels at home, one of the first questions is: how many kW or kWp solar system do I actually need?
The answer depends on your monthly TNB bill, estimated electricity usage, daytime electricity pattern, roof condition and residential supply type. This Solar100 calculator gives you a simple starting estimate before you request quotations from solar installers.
It is especially useful for homeowners who ask questions such as: “How many kW solar do I need for a RM400 TNB bill?” or “Should I compare 4kWp, 5kWp or 6kWp solar packages?”
For a RM400 monthly TNB bill, many Malaysian homeowners may start by comparing a solar system around 4kWp to 6kWp. For a RM500 bill, the starting comparison may be around 5kWp to 7kWp. For RM800 and above, a larger system may be worth checking.
However, the correct system size should not be based on bill amount alone. Daytime usage, roof space, shading, supply type and Solar ATAP requirements must also be considered.
Fill in a few simple details to estimate the solar system size you should start comparing. Your result will be sent to Solar100 WhatsApp for basic suitability checking.
Your area helps Solar100 check suitable installer options near your location.
Your phone number will be included in the WhatsApp message for follow-up.
Enter your average monthly TNB bill. Example: RM300, RM400, RM500, RM800 or RM1,000.
This is only for a simple sizing estimate. Final capacity depends on technical assessment, roof space and latest approval requirements.
Solar generates electricity during the day. Homes with higher daytime usage may benefit from a larger solar system.
After clicking the button, WhatsApp will open with your estimated result. Please review the message and tap send so Solar100 can help check your solar suitability.
Suggested Solar System Size to Compare:
----
This is a simple sizing estimate only. Actual solar system size depends on roof space, shading, roof direction, electricity usage pattern, installer design and latest Solar ATAP requirements.
Your monthly TNB bill can provide a starting point for estimating solar system size. However, it should not be the only factor. A home with a RM400 monthly bill may require a different system size from another home with the same bill if their daytime usage and roof condition are different.
As a rough starting guide, you can compare the following solar system size ranges:
| Monthly TNB Bill | Solar System Size to Start Comparing | Who Should Check This? |
|---|---|---|
| RM300 | 3kWp – 4kWp | Small to medium homes with moderate usage |
| RM400 | 4kWp – 6kWp | Common family homes starting to compare solar |
| RM500 | 5kWp – 7kWp | Homes with higher air-cond or daytime usage |
| RM800 | 7kWp – 10kWp | Larger homes or high-usage households |
| RM1,000 | 9kWp – 12kWp | Large homes, high usage or three phase users |
This table is only a starting reference. The final system size should be confirmed with a qualified solar installer after checking roof condition, system design and actual electricity usage.
Solar panels generate electricity during daylight hours. This means your solar savings are usually better when your home uses more electricity during the day.
If your home uses most electricity at night, installing a larger solar system may not always improve ROI. If people are at home during the day, or if you use air-conditioning, water pumps, kitchen appliances or work-from-home equipment during daylight hours, a larger system may be easier to justify.
Do not choose solar system size based only on the biggest package offered by an installer. An oversized system may increase installation cost without giving matching savings. A good solar proposal should explain why the recommended kWp size fits your electricity usage.
The right solar system size depends on more than your electricity bill. Before signing a quotation, check these items carefully:
If an installer has already proposed a system size and quotation amount, you should check whether the quoted price is reasonable for your TNB bill and expected payback.
Solar100 helps Malaysian homeowners understand what solar system size they should start comparing before requesting quotations. After using the calculator above, your WhatsApp message will include your area, monthly TNB bill, estimated system size, expected generation, estimated savings and cost range.
This helps Solar100 check:
Use the calculator above and send your result to Solar100 WhatsApp. We can help you do a basic solar suitability check before you compare installers.
Malaysia