年度燃料利用效率: The Annual Fuel Utilization Efficiency (AFUE) rating, indicates how well a furnace converts energy into usable heat. The rating is expressed as a 百分比age of the annual output of heat (output rating in Btus -- British thermal units, a measure of energy) to the annual energy input to the furnace (input rating in Btus).
84%到89%的评分并不常见. Acidic condensate, harmful to the furnace, forms at these 百分比ages. 公法不. 100-12, 通过年, requires that all gas furnaces manufactured after January 1, 1992, 至少有78%的AFUE.
大气排气燃烧: If a chimney is available, furnaces with this system are the least expensive to install. 大气通风炉 afue为60- 65% 当配备了站立的飞行员，和 afue为63- 70% 配备电子点火系统时. With special vent dampers, atmospheric vent units can achieve afue为78- 80%.
冷凝(或休养装置): These units are super efficient with some designs reaching afue高达97%. 不像传统的强制空气炉, condensing units capture most of the water vapor and heat contained in hot flue gases that would normally escape up the chimney. The escaping gases then pass through a second heat exchanger and condensate is expelled. The heat exchangers are made of corrosion-resistant stainless steel, 而且很多都有终身保修. Exhaust is cooler than that of conventional furnaces and can be vented with PVC piping.
下流式或逆流炉: These units have a blower at the top to draw air into the furnace. 加热的空气在底部被吹出. This type of furnace is used to supply floor duct systems.
电子点火: An electronic ignition eliminates the need for an energy-wasting standing pilot. 燃料只在需要时使用. 飞行员被电火花点燃.
热交换器: The heat exchanger is a metal chamber in the furnace that houses a gas burner. The flame produced by the burner heats the chamber. 当室外变热时, the air surrounding it is warmed and used to heat the house. Improved designs enhance efficiency and provide quieter operation.
水平流炉: Air travels horizontally from one side of the heater, 穿过热交换器, 热空气从另一边吹出来. This type of furnace is installed in areas with limited headroom, such as attics or crawl spaces. They can also be installed below floors or suspended below ceilings.
权力燃烧: 在这个系统中，燃烧是由鼓风机产生的. The blower pushes the combustion gases through the vent, and regulates the amount of combustion air. Power combustion furnaces do not require a draft hood. This reduces off-cycle losses and improves efficiency. 许多动力燃烧炉在 78 - 80年AFUE百分比. When equipped with an additional heat exchanger, they can operate at afue为90- 96%.
脉冲燃烧: (这些型号列在冷凝炉下面.) Pulse combustion is produced by self-perpetuated "pulses." This unique system mixes air and fuel in a sealed combustion chamber. A spark ignites the mixture, and the resulting increase in pressure closes the gas/air inlet valve. The combustion products are forced through an exhaust pipe and the pressure in the combustion chamber drops, 重新打开进气阀. The next combustion cycle is ignited by the heat remaining from the previous cycle. This process repeats itself about 60 times per second. 采用这种燃烧系统的炉子有 afue从91- 97%. Exhaust gases, at 100-200 degrees Fahrenheit, are cool enough to vent through PVC piping.
密封燃烧: Sealed combustion systems draw in all the air used for combustion from the outside, 废气直接排到室外. Since cold outside air is not mixed with the warm indoor air during combustion, 的效率会提高. Furnaces with this type of combustion system have an AFUE范围70-80 百分比.
上升气流炉: These units have blowers at the bottom that draw air into the furnace. 加热的空气从顶部吹出去. These heaters can be installed in utility rooms, closets or basements.
通风器: The vent damper is a "flapper" device installed in the flue. 当热需求得到满足时, 阻尼器关闭, trapping residual heat for circulation in the home. 当需要热量时, the damper opens before the burners are ignited to allow combustion fumes to escape. The damper remains open only as long as the burners are on. 如果风门关闭，燃烧器就不能点燃.
定义 courtesy of The National Propane Gas Association