AFUE is an acronym for Annual Fuel Utilization Efficiency and is the metric used to measure furnace efficiency. It is simply a ratio between the amount of fuel converted to heat and the amount of fuel which enters the furnace. The higher the AFUE the more efficient the furnace.
The condensing furnace is so efficient and extracts so much heat from the combustion process that its exhaust vent / flue is just warm to the touch, not “burn your fingers hot” like a conventional furnace.
So what makes the conventional furnace and condensing furnace so different, and how does the condensing furnace work? Well, that’s what I’ll explain in this tutorial called Anatomy of a High Efficiency Condensing Furnace. In this tutorial you’ll learn the following about a condensing furnace and its components:
- How a Condensing Furnace is Different
- Overview of how a condensing furnace works
- Air Recycling / Fresh Air Intake
- Cold air return
- Heat recovery ventilator (optional accessory)
- Air filter
- Electric blower motor
- Blower compartment
- Fuel Combustion
- Gas burner
- Electronic ignition
- Combustion chamber
- Combustion air intake
- Heat Extraction
- Primary heat exchanger
- Secondary condensing heat exchanger
- Condensate drain line
- Combustion Exhaust
- Draft inducing fan
- Plastic flue gas vent
