Key Differences Between KVA And KW for Choosing The Right Generator

Before investing in a diesel generator for your facility or project, it’s essential to understand the technical specifications that determine its performance. Two key terms—kVA and kW—often cause confusion among buyers. Although they both refer to power, they represent different aspects of it. Understanding how they differ is critical to choosing the right generator for your specific needs.

kW (kilowatt) represents real power, which is the actual amount of power that can be used to run electrical equipment. It’s what your machines, lights, and appliances consume to perform work.

kVA (kilovolt-ampere), on the other hand, measures apparent power, which includes both real power (kW) and reactive power (kVAR). Reactive power is used to maintain voltage levels in the system but doesn’t perform useful work.

While kW shows the usable output, kVA reflects the total capacity of the electrical system—including energy lost to inefficiency.

The link between kW and kVA lies in the power factor (PF). This is a ratio that measures how efficiently power is being used, and in most industrial generator applications, it is standardized at 0.8.

The formula is simple:

kW = kVA × Power Factor

For example, if you have a 125 kVA generator with a power factor of 0.8, the real usable power output is:

125 × 0.8 = 100 kW

This power factor accounts for energy lost to things like heat, magnetism, and resistance. It’s particularly relevant in environments with motors, transformers, or inductive loads.

Let’s consider how this applies in actual settings:

Office Building Example: A 100 kVA generator (with PF = 0.8) delivers 80 kW of usable power. This capacity is suitable for maintaining lighting, elevators, and HVAC systems in a medium-sized office complex.

Industrial Workshop Example: Suppose your machinery demands a continuous load of 120 kW. To meet this need, you’ll require a generator rated at least 150 kVA (since 150 × 0.8 = 120 kW). Choosing a smaller unit could result in overload and operational failure.

Backup Power for Hospitals or Data Centers: These facilities have critical systems and often require higher kW loads with little tolerance for downtime. Here, sizing based on kW—then converting to kVA—is essential for reliable power continuity.

These real-life comparisons demonstrate why understanding both units is more than just technical knowledge—it’s a practical necessity.

Correctly distinguishing between kW and kVA is essential for generator buyers. An undersized generator risks equipment failure, while an oversized one leads to higher costs and wasted fuel. Improper sizing can also void warranties and shorten generator life. For export clients and infrastructure projects, understanding these details is vital for reliable power supply.

To determine the correct generator size, first assess the total simultaneous electrical load measured in kilowatts. Next, convert this value into kilovolt-amperes by dividing by the power factor. It is important to choose a generator with a kVA rating that accommodates this load, plus additional capacity for potential expansion or standby use. If uncertainty remains, our technical team is available to provide customized advice, ensuring customers select the most suitable and cost-efficient generator.

The unit kW indicates the actual power your equipment consumes, whereas kVA reflects the total capacity of the generator, including losses within the system. These two values are linked by the power factor, which is typically 0.8. Understanding this relationship enables buyers to make informed decisions, avoid costly errors, and ensure reliable generator performance for any application. With extensive experience in exporting diesel generators, we provide comprehensive support from sizing to delivery.