Infrared heaters are located on the ceiling or wall directly above the areas where you will be located or the object to be heated such as in snow melting. The air in the entire room is not heated because infrared heats objects not air, so you would be kept warm even in a relatively cold room. This is ideal if you will only be located in a couple areas or if you will be coming and going from the areas. Some comfort heaters use a quartz glass heating element and some use a metal sheath tubular element. It is approved to use most types of infrared heaters and reflectors outdoors, providing it is entirely shielded from rain and wind driven rain. The Fostoria RPH heaters and the Fostoria Multi-Mount are both UL listed for completely exposed/unprotected outdoor applications. The advantage of quartz is a higher percentage of infrared versus convection heating.  Metal heaters last longer, and are not as subject to damage from environmental factors. Quartz heaters emit light and metal do not.  In outdoor applications quartz lamp heaters are typically used because they are less susceptible to heat loss due from wind because of their far lower mass, (more infrared is emitted because there is less mass to hold heat which can be lost to a rise in temperature of the air crossing it) and they reach higher temperatures than metal heaters.