Shopping for solar can feel like learning a new language. Quotes are full of kW this and kWh that, plus scheme names and acronyms that nobody stops to explain. It is easy to nod along and hope for the best, but understanding a few key terms puts you in a much stronger position to compare offers and ask good questions. So here is a friendly, jargon-free glossary of the words that matter most, written for homeowners rather than engineers.
The units: kW, kWp, kWac and kWh
kW (kilowatt) is a measure of power, or how much electricity something uses or produces at a given moment. kWp (kilowatt-peak) describes the size of your panel array, meaning the maximum power it can produce under ideal conditions. When someone says you need a 5kWp system, they are describing the size of the panels on your roof.
kWac refers to the alternating current capacity of your system, essentially the usable output after the inverter. This one matters in Malaysia because the SuRIA Home rebate is calculated per kWac, paying RM600 for each one, up to RM3,000. Finally, kWh (kilowatt-hour) is a unit of energy, and it is what you are actually billed for. It measures power used over time, so a 1kW appliance running for one hour uses 1kWh. Your TNB bill is simply a count of the kWh you consumed.
The hardware: panel, inverter and battery
A solar panel, or module, is the glass and silicon unit on your roof that turns daylight into direct current electricity. The inverter is the brain of the system, converting that direct current into the alternating current your home uses and managing the flow of energy. A battery, where fitted, stores electricity so you can use your own solar power after dark or during an outage. You can read more on our battery storage page. If the technical side of how these connect interests you, our article on how solar panels work walks through it step by step.
The current: DC and AC
DC (direct current) is the raw electricity your panels produce. AC (alternating current) is the form of electricity your home and the grid actually run on. The inverter exists to bridge the two, turning panel DC into household AC. That is really all you need to remember about the difference.
The scheme: Solar ATAP and export credits
Solar ATAP is Malaysia's current rooftop solar programme, which replaced the older Net Energy Metering, or NEM, scheme. Under it, the surplus electricity your system exports to the grid earns you credit that offsets what you draw later. Our dedicated page on Solar ATAP explains how it works in full. You may still hear NEM mentioned, which was the previous version of this idea.
The performance words: degradation and payback
Degradation is the small, gradual drop in a panel's output over the years, usually a fraction of a percent annually, which is why panels still perform well after decades. Payback period, sometimes called break-even, is how long it takes for your accumulated savings to equal what you spent on the system. After that point, the electricity your system produces is essentially free.
The paperwork: SEDA and TNB
SEDA, the Sustainable Energy Development Authority, is the government body that administers the rooftop solar scheme. TNB, Tenaga Nasional Berhad, is the utility that runs the grid, connects your system and pays out the rebate. The good news is you rarely deal with either of them directly, because a proper installer handles the applications for you. Our page on how it works shows where each fits into the journey.
Now you can talk solar
That is the core vocabulary. Once these terms click, quotes stop looking like alphabet soup and start making sense, which makes it far easier to compare options and spot a fair deal. And if any term on your quote is still unclear, that is exactly what a free consultation is for. We are happy to talk you through every line in plain language, so you understand precisely what you are buying before you decide.