Modified Sine Wave Inverters
The least expensive type of modern inverter produces modified sine wave power. The waveform looks like a stair-step, where the power rises straight from zero to upper peak voltage, straight back to zero, and straight to lower peak voltage, resting at each point for a moment.

Modified sine wave inverters will run many household appliances such a televisions, radios and microwaves with occasional minor electrical "noise" present. Sensitive equipment like battery chargers, tools with variable speed motors, laser printers and certain heating controllers will run erratically or not at all with modified sine wave power.

For a remote cabin with only the "basics" running on the electrical system, a modified sine wave inverter is an economical choice. Modified sine wave inverters are also often well suited for solar-powered RV electrical systems.

True Sine Wave Inverters
The power supplied by utility companies and engine generators is a true sine wave form. This is the most reliable waveform for household use. True sine wave power passes from the upper and lower peak voltages in a smooth curved wave, rather than the stair-step of the modified sine wave.

All appliances and electronic equipment will run as intended when using sine wave power. True sine wave inverters will produce AC power as good as or better than utility power, ensuring that even the most sensitive equipment will run properly. While sine wave inverters are more expensive than modified sine wave models, the quality of their waveform can be a definite advantage.

For office buildings and industrial installations considering a backup power inverter, a true sine wave model will allow proper function of all electronic equipment and fluorescent lighting. For residential power, anyone using a battery chargers, electric drills, digital clock radios or other sensitive electronics should consider a true sine wave inverter to ensure proper function of all household appliances.