The short answer
Inverter generators produce stable, low-distortion power and are usually quieter and more fuel-efficient at light loads. Open-frame generators usually cost less per watt and suit tools and appliances. Compare the catalog's inverter table with the lowest cost per watt.
Side by side
| Inverter generator | Open-frame generator | |
|---|---|---|
| Power quality | Low distortion; kinder to electronics | Adequate for tools and most appliances |
| Noise | Typically quieter (compare stated dB with care) | Typically louder |
| Fuel use at light load | Engine speed adjusts to load | Engine runs at a fixed speed |
| Cost per running watt | Usually higher | Usually lower |
| Weight and size | Smaller models are portable | Larger frames, often with wheels |
| Parallel two units | Often supported | Rare |
Total harmonic distortion (THD) is listed for some models; where a maker states it, our generator pages show it.
Choosing
- Choose inverter for quiet neighborhoods, laptops and routers, and smaller loads.
- Choose open-frame for the most watts per dollar, heavier loads and a transfer-switch setup where noise matters less.
- Whichever you pick, run it outdoors and size it by running and starting watts.
SafetyNeither type is safe indoors. Carbon monoxide risk is the same.
Figures marked as Wattstanding calculations show their working; product figures come from the sources on each product page. How we work