Understanding kW vs kVA: What’s the Difference and Why It Matters for Your Backup Generator
The Ultimate Guide from American Energy Solutions
If you’re researching backup power systems, you've probably come across the terms kW (kilowatt) and kVA (kilovolt-ampere). While they might seem interchangeable, there’s a crucial difference — one that can affect the performance, efficiency, and cost of your industrial generator setup.
At American Energy Solutions, we help businesses across the country—from data centers and aggregate plants to cannabis cultivation sites, cold storage facilities, and disaster relief operations—choose the right Caterpillar diesel or natural gas generator by correctly understanding kW vs kVA.
The Short Answer:
kW (kilowatts) is actual usable power.
kVA (kilovolt-amperes) is apparent power, or total power drawn from the generator.
The ratio between them is defined by something called the power factor (PF).
Understanding the distinction is absolutely essential when sizing a generator, selecting a transfer switch, or planning your electrical load distribution for mission-critical systems.
What is kW in Power Systems?
kW, or kilowatt, is the real power that actually performs work. This is the power that runs your:
Motors
HVAC systems
Lighting
Servers
Refrigeration units
Pumps
Compressors
In other words, kW is the power your equipment consumes.
1 kW = 1,000 watts
When you look at your utility bill or calculate the true load of a facility, you’re almost always dealing with kW.
What is kVA in Backup Generators?
kVA, or kilovolt-amperes, represents the apparent power. It’s the total power a generator must be capable of providing — including both the real (kW) and reactive (non-working) power.
Reactive power is created by devices like:
Inductive motors
Transformers
Ballasts
Variable frequency drives (VFDs)
These components don’t use power in the traditional sense, but they still draw current and impact how much capacity your generator set needs.
The Power Factor: Bridging kW and kVA
The power factor (PF) is a number between 0 and 1 that represents the efficiency of your system. For most commercial and industrial applications, the standard power factor is 0.8 (or 80%).
Formula:
kW = kVA × Power Factor
Example:
If you have a 500 kVA generator at 0.8 power factor:
500 kVA × 0.8 PF = 400 kW usable power
This means the generator can deliver 400 kW of real power, and the rest is reactive.
Why kVA vs kW Matters When Sizing Your Generator
When buying a generator, mistaking kVA for kW can lead to:
Undersized systems that can’t carry your full load
Frequent shutdowns or system overloads
Reduced equipment life and warranty voidance
Non-compliance with local codes or emissions regulations
At American Energy Solutions, our experts always guide customers through this sizing process to ensure they get the right generator, properly rated for their real-world needs.
Typical Power Factor by Application (Helpful for Generator Sizing)
Application Type
Typical Power Factor
Data Centers
0.95 – 1.0
Manufacturing Facilities
0.8 – 0.9
Aggregates / Mining
0.7 – 0.9
Cannabis Grow Operations
0.85 – 0.95
Cold Storage Facilities
0.9 – 1.0
Hospitals / Labs
0.9 – 1.0
Construction / Rentals
0.8 (assumed)
Each application behaves differently. For example, a cold storage facility with heavy refrigeration will draw less reactive power than a quarry with dozens of motors starting simultaneously.
Caterpillar Generators: Built to Handle Any Power Factor
At American Energy Solutions, we stock and supply a vast inventory of good used Caterpillar generator sets ranging from 20 kW to 4000 kW, available in both diesel and natural gas configurations.
Our units are built to deliver dependable power with flexible power factor support, including:
Standby generator sets for emergency backup
Prime-rated units for continuous or remote operations
Automatic Transfer Switch (ATS) compatible systems
Microgrid-ready solutions with real-time load balancing
All systems are available with load bank testing, commissioning, and custom control panel upgrades to support specific power factor demands.
kW vs kVA: Real-World Scenarios
Example 1 – Aggregate Facility
Total actual load: 750 kW
With PF of 0.8 → Required generator: 937.5 kVA
If you incorrectly purchase a 750 kVA generator (assuming it provides 750 kW), your system will only deliver 600 kW of usable power, and it will likely overload and shut down during operation.
Example 2 – Data Center
Load: 1200 kW
PF of 0.95 → Required generator: 1263 kVA
Buying a 1250 kVA unit may fall short during peak usage or battery charging surges. In this case, upsizing slightly ensures power stability.
Why Work With American Energy Solutions?
Industry-Leading Inventory: Caterpillar generators, Tier 4 Final units, mobile and stationary options
Expert Guidance: Our team will walk you through every step — from sizing and load calculations to installation
Custom Solutions: Power systems tailored for your site, your application, and your compliance requirements
Ongoing Support: Full-service maintenance, diagnostics, and emissions compliance support
Don’t Guess — Size It Right the First Time
At American Energy Solutions, we make it simple to understand your real load, convert kW to kVA properly, and select the perfect backup power system to protect your business, your productivity, and your peace of mind.
Whether you’re powering a cold storage warehouse, a cannabis greenhouse, or an off-grid aggregate site, we’ve got the expertise and inventory to deliver.
Get Expert Help with Your Generator Sizing Today
📞 Call our generator experts to discuss your load profile
📧 Email us specs for a free sizing consultation
🔗 Visit www.americanenergysolutions.com
When reliability matters most, trust the experts at American Energy Solutions — powering your future, one generator at a time.