It's difficult to make general claims about infrared heaters because there are so many different specifications. First, there's the fuel/energy source. As we mentioned earlier, infrared heaters can be powered by electricity, natural gas or propane - if you're looking for an electric model, you should check how many volts and Hz are used. Different heaters also have different heat outputs and maximum operating temperatures. Some heaters also come with timers [sources: Tools For Wellness].
Other specifications include: filter controls, wheels, weight, fan, thermostat and color. Design also plays a role. Usually, you'll find a protective cover over the heating element, which can can be made from as copper, iron, steel or brass [sources: Ramson Solutions, Global Spec].
Read the next page in order to find out why some claim that infrared heaters are more environmentally friendly than other heat sources.