新炉子有指示灯吗？
newer furnaces (since around 2010) use electronic ignition systems, and do not have a pilot light. an electronic ignition creates a flame/spark when needed, but does not require a constant flame or 'standing pilot'. these newer systems are safer and more reliable. also, because a conventional pilot lights burns all times, they use more gas, which is not efficient. electronic ignitions are replacing pilot lights in many gas-burning appliances in addition to furnaces.
afue stands for annual fuel utilization efficiency. afue (represented as a percentage) indicates how efficient your furnace is. a higher afue rating means greater energy efficiency. if you have an afue of 82%, it means that 82% of the fuel energy put into the system is used to heat your home, while the remaining percent is lost somewhere in the heating process. all furnaces have some loss. this loss is specific to the furnace, and doesn't account for heat loss in ductwork, vents, etc. a typical furnace will have a rating in the mid 80s and a high-efficiency furnace should be 90% or more.