Inverter vs. conventional generators
Once you know what size you need, the next decision is type. The two work the same way mechanically — an engine spins an alternator — but they deliver very different electricity.
What "clean power" actually means
A conventional generator's output voltage and frequency wobble with engine speed. An inverter generator takes the raw AC, converts it to DC, then inverts it back to a stable, pure sine wave. Total harmonic distortion (THD) under ~3% is typical for inverters versus 9%+ for open-frame units. That matters for anything with a microprocessor: laptops, TVs, furnace control boards, CPAP machines, and modern refrigerators.
Head-to-head
- Power quality: Inverter wins — safe for all electronics. Conventional is fine for resistive loads and basic motors, risky for sensitive gear.
- Noise: Inverter wins by a lot. A 2,000 W inverter runs ~50–60 dB (conversation level); an open-frame 7,500 W unit is ~72–78 dB (vacuum cleaner at close range). Enclosed inverter housings and variable engine speed do the work.
- Fuel efficiency: Inverter wins at partial load — the engine throttles down to match demand instead of screaming at 3,600 RPM all day. At full load the gap narrows.
- Cost per watt: Conventional wins, decisively. Open-frame portables run roughly half the price per watt of inverters at the same output.
- Weight/portability: Inverter wins at small sizes (a 2,200 W inverter weighs ~47 lbs). At 7,500 W+ both types are heavy; neither is fun to lift alone.
- Parallel capability: Many inverters can be paired for double output — handy if your needs grow.
Which type for your use case?
- Camping / RV / tailgating: Inverter, no contest. Noise limits at campgrounds often cap you at 60 dB anyway, and you'll be charging phones and running a TV.
- Home backup (essentials): Either works. If the furnace has an electronic control board (most modern ones do), lean inverter — or at least verify the board tolerates conventional power.
- Jobsite / power tools: Conventional open-frame. Tools don't care about THD, and watts per dollar is what matters. The noise is already a non-issue on a jobsite.
- Whole-home backup: That's standby-generator territory (installed, automatic), a different purchase entirely.
Fuel: gas, propane, or dual-fuel?
Most portables burn gasoline; dual-fuel models add propane. Propane stores indefinitely (gasoline goes stale in months without stabilizer), burns cleaner, and is easy to stockpile — at the cost of ~10% less power and shorter runtime per tank. For emergency backup you may use twice a decade, dual-fuel is worth the premium.