Generator vs. Inverter: What is an Inverter Generator?
Regular generators and inverter generators are very similar devices that convert the chemical energy of the fossil fuel into mechanical energy (rotation of the internal combustion engine and electric generator) and mechanical energy into electric energy.
However, although their operation is very similar, internally there are several, very important differences...
Inverter Generator vs. Regular Generator
The main difference between the inverter generators and the regular generators is that in order to keep the AC output voltage frequency more or less constant, regular generators must spin their internal combustion engines at a constant speed all the time.
For example, in order to achieve 50Hz output, internal combustion engines spin at 3000 RPM, and to achieve 60Hz output, internal combustion engines spin at 3600 RPM.
The output voltage has a form of the sine wave, but with plenty of harmonic distortions, sometimes with more than 20% THD, which can cause issues when powering sensitive electronic and electric devices.
Also, since the engine is spinning rather fast even when there is no load present, regular generators are less efficient, they create a lot of noise, they require more maintenance and they don't last as long as inverter generators.
On the other hand, inverter power generators feature built-in electronics that 'store' the electric energy in the capacitors and using electronic converters (also known as "inverters") generate electricity of required voltage, frequency, and waveform.
Note: this is a very simplified description of the inverter technology commonly found in inverter power generators!
This allows the engine to spin at the optimum speed, increasing fuel efficiency, decreasing the noise, increasing the engine lifetime, simplifying the maintenance, and similar.
Also, the amount of Total Harmonic Distortions (THD) in inverter generators are very often <3% at nominal power, allowing these units to directly power sensitive devices like laptops, TVs, multimedia units, and similar.
Regular Generator or Inverter Generator: Which One to Choose?
For most residential and commercial applications, inverter generators are recommended choice - actually, for units up to 5 kW of output power, it is rather hard to find power generators that are not based on inverter technology.
Some of the most popular, rather quiet inverter generators are given in the following comparison chart:
|6.5h @50%||52 dB @25%
58 dB @50%
|AC: 120V 20A 5-20R, 120V 30A L5-30R
DC: 12V 8.3A, USB 5V
|Champion 2000W Model #100402||2000/1800W
|11h @25%||53 dB @25%||AC: 20A 120V 5-20R Duplex
DC: 12V 8A
|Champion 2000W Model #100692||1700W
|11.5h @25%||53 dB @25%||AC: 20A 120V 5-20R Duplex
|11h @25%||50 dB @25%
56 dB @75%
60 dB @100%
|AC: 20A 120V 5-20R Duplex
DC: 12V 5A
|45* dB||AC: 120V 20A Duplex 5-20R, 120V 30A L5-30R
DC: two USB ports (5V/2.1A, 5V/1A)
|8h @25%||50 dB @25%||AC: 20A 120V Duplex
|48 dB @25%
57 dB @100%
|AC: 20A 120V Duplex
DC: 12V 100W (8.3 Amps)
|20h @25%||50 dB @25%||AC: 120V 20A Duplex, 120V 30A L5-30R|
|10.8h @25%||51 dB @25%||AC: 2x NEMA 5-20R
DC: 12V, 2x USB 5V (1A, 2.1A)
|10.5h @25%||51 dB @25%||AC: 15A 120V NEMA 5-20R Duplex
DC: 12V, USB 5V (2.1A, 1A)
|10h @25%||52 dB @25%||AC: 20A 120V Duplex
DC: 12V, 2x USB 5V
|18h @25%||52 dB @25%||AC: 120V 20A 5-20R Duplex, 120V 30A TT-30R
2x USB 5.0V (2.1, 1.0 A)
|10.5h @25%||51.5 dB @25%||AC: 120V Duplex
DC: 12V 8A
|8.6h @25%||53 dB @25%||AC: 120V Duplex
DC: 12V 8A
Note: Amazon affiliate links ('Model' Column) open in the new windows, feel free to check them for the most up-to-date offers and prices.
Of course, there are many more inverter generators on the market, but these units are exceptionally quiet considering their output power, making them the preferred choice for residential use, camping, tailgating, and other off-the-grid applications and of course, in emergencies.
Note: Power generators, both regular and inverter generators, MUST be kept outside, down the wind, during operation - they produce fumes that contain carbon monoxide (CO) which is very dangerous to humans and animals. For exact safety procedures, please, check the Owner's Guide of the generator that You have.
Just to clarify few things, here are few additional notes:
Power Inverter vs. (Power) Inverter Generator
Power inverters are electronic devices that convert electric energy, usually from the deep cycle batteries, of one form (usually 12V, 24V, 36V, 48V DC) into electric energy of another form, usually AC electricity - 120V, 220V, single-phase, triple-phase, and similar.
Very often, power inverters have USB ports for direct charging of smartphones, tablets, and similar devices.
Also, power inverters during operation don't emit any fumes and can be used indoors, unlike power inverter generators.
For more information about these units, feel free to check out the Power Inverters page.
Power Station vs. Power (Inverter) Generator
Power stations are devices that combine built-in deep cycle, usually lithium batteries and power inverters in single units.
As such, they can be used both indoors and outdoors, since they don't emit any fumes.
Also, they are very quiet during the operation.
However, the operating time of the power stations is limited by the amount of energy stored at the local battery.
For more information about these units, feel free to check out the Best Portable Power Stations page.
Fuel Cell vs. Power (Inverter) Generator
A fuel cell is an electrochemical device that converts the chemical energy of hydrogen into electricity through a pair of redox reactions.
Unlike batteries, fuel cells require a continuous source of fuel and oxygen to sustain the chemical reaction.
In essence, fuel cells can be considered as devices "between" the batteries and power (inverter) generators - fuel cells "burn" hydrogen using oxygen from the air and produce electricity and water as a byproduct.
Fuel cells are much more efficient than internal combustion engines, with efficiency in the 50-60% range, which is better than the efficiency of large diesel engines that go up to 40-50%.
Also, to increase the efficiency of the fuel cells, thermal energy can be captured and used for other purposes, the efficiency of fuel cells can rise to 80-90%.
Just for comparison, when the lead-acid battery is discharged in one hour, its efficiency is in the 50-60% range, with lithium batteries featuring efficiency in the 80-90% range, with newer models having efficiency >90%.
Note: the efficiency of the batteries, especially lead-acid batteries, depends on the drain current, temperature, and similar.
The fuel efficiency of the power generators depends on the engine type (two or four strokes), fuel type (gas/propane/natural gas/diesel), generator load and can be anywhere from 10-15% to ~30%. Large diesel generators can operate at 35-45% efficiency, but those are large industrial units with turbochargers, intercoolers, and similar features that increase the complexity of the power generator, but also increase the efficiency of the unit.
Long Story Short: the main difference between regular power generators and inverter power generators is the output controller (inverter) found in inverter power generators, allowing them to be more fuel-efficient, to require less maintenance, generate less noise, and to have output power with less THDs, often under 3%.
Again, never, but really never operate any power generator indoors ...