Furnace efficiency standards are set by the United States
Department of Energy, in conjunction with heating, ventilation
and air conditioning manufacturers, utility companies, and other
interested parties. Federal laws require a minimum level of
efficiency for furnaces, which is measured in percentages of the
energy input. The National Appliance Energy Conservation Act
recently raised the minimum efficiency requirements for furnaces
from sixty-five percent to between seventy-eight and eighty
percent. The two percentage point difference depends on whether
the furnace is located inside the house or outside, such as in
the garage. For every unit of energy that is input, there is a
certain amount that is output in the form of heat - as in the
case of the furnace. For example, if your furnace has an
efficiecy rating of eighty, that means that it will output
eighty percent of the energy it takes in. Most major appliances,
including furnaces, have an Energy Guide label on them that will
tell the consumer how that ap