What is the difference between a low frequency and high frequency inverter?

Low frequency (LF) inverters use a large transformer operating at 50–60Hz to convert DC to AC. High frequency (HF) inverters use a smaller switching transformer operating at 20,000–100,000Hz, then convert to 60Hz output. LF inverters are larger and heavier but handle surge loads better (2–3× rated power for several seconds). HF inverters are compact and lightweight but typically only surge to 2× rated power briefly. For van builds, most HF inverters are adequate unless running large motor loads.

Should I get a low frequency or high frequency inverter for my van?

For most van builds: a high frequency inverter is fine and the practical choice. HF inverters are lighter, smaller, more efficient at partial load, and cheaper. A low frequency inverter is worth considering only if you run very high startup-surge loads (large air compressors, big motors, welders) regularly. For laptop, induction cooking, coffee maker, and similar loads: high frequency is better value.

Low Frequency vs High Frequency Inverter: Which Is Better for a Van?

The low-frequency vs high-frequency inverter distinction comes up frequently in van electrical discussions, usually accompanied by strong opinions. Here's what the difference actually means and which matters for a van build.

How they work

High frequency (HF) inverters — also called "switch-mode" inverters — convert DC to a very high frequency (20–100kHz), then use a small transformer to step up voltage, then convert to 60Hz AC output via electronics. The high-frequency switching allows a much smaller, lighter transformer.

Low frequency (LF) inverters use a large, heavy transformer operating at the output frequency (60Hz). The DC is pulsed directly through this transformer. The transformer is what you see when you pick up a 2,000W LF inverter and notice it's very heavy.

Practical differences

Characteristic	High frequency	Low frequency
Size & weight	Compact, lightweight	Large, heavy
Surge capacity	Typically 2× rated (briefly)	Typically 2–3× rated (sustained for seconds)
Efficiency at partial load	Very good (85–95%)	Good (80–90%), drops more at light loads
Price	Lower for same wattage	Higher for same wattage
Reliability	Good; heat is the enemy	Transformer failures are rare; very robust
Motor load handling	Adequate for most	Better for large motors

For van builds

High frequency inverters are the right choice for the vast majority of van builds. Common van loads — induction cooking, laptop, CPAP, coffee maker, phone charging — are either resistive (induction, coffee maker) or electronic (laptop, phone). Neither requires the sustained surge capacity of a low frequency inverter.

The Renogy, AIMS, and budget pure sine inverters that dominate van builds are all high frequency. The Victron MultiPlus is also high frequency. None of this is a problem for typical van loads.

Consider a low frequency inverter if:

You run large electric motors regularly (air compressors, workshop tools, heavy A/C units)
You need the deepest possible surge capacity and are willing to accept the size and weight penalty
You're building a high-power truck or RV system with loads over 3,000W

AIMS and Samlex make popular low frequency inverters for the RV market. They're heavier but well-regarded for rugged use.

The real metric: check the actual surge rating

Rather than choosing LF vs HF by label, look at the actual surge spec:

What is the peak/surge wattage?
For how long can it sustain the surge (milliseconds vs seconds)?

A 2,000W HF inverter with a 4,000W surge for 1 second handles most motor startups just fine. A 2,000W LF inverter with a 6,000W surge for 5 seconds handles larger and slower-starting motors.

For laptop and induction cooking: either is fine. For 2HP air compressors: low frequency wins.