Foggers are machines that produce a dense cloud of brief duration. Carbon dioxide can be used to generate a white cloud that stays low to the ground. The thickness of the vapor and its directionality can be very effective outdoors, according to EventSolutions.com. Hazers are machines that emit fog for extended periods, but it is lighter and more suitable for indoor special effects with lights.
Most foggers are water-based and use heat to boil a "fog fluid," which consists of water mixed with glycol. Much like an electric teakettle, the fog machine heats up and releases steam and fog fluid into the air. Fog remains in the air as the steam cools. Fog fluid is considered nontoxic and safe for use. Hazers may be oil-based and remain cool when operating. The fluid used in hazers is also nontoxic, but oil may coat the floor with a slick film during use.
The wattage of fog machines ranges from about 400 to 1000 watts, according to GotFog.com. More powerful machines capable of generating more fog.
While a small fog machine may be suitable for a small backyard party, combining at least two machines and using machines with different power ratings may be necessary for larger venues. Foggers and hazers may also be used together for added effects. Also, using a timer remote allows a user to preset when the machine goes into operation and releases fog. Otherwise, manual control is necessary.