Here in Michigan, most people use a central forced-air system to heat their homes. At the base of this system is the furnace. Most people know that their home furnace produces heat but know little else about the parts that make up what is often the largest appliance in your home. We want you to understand these features, particularly the 3 main components that make up a typical furnace.
1. The Burner
The burner is what combusts (burns) fuel to create heat. That fuel in Michigan is most likely natural gas, propane (lp gas), or fuel oil. Most people install a furnace that handles the fuel source that is most readily available in their area.
Burners can be single-stage, two-stage, or multi-stage (modulating). This refers to the actual level of heat the furnace burner produces. Think of it like a bonfire you might have outside one cool fall night. A single-stage furnace only burns a set amount of fuel at one level.
In contrast, a two-stage furnace can burn at two levels, low and high, depending on the amount of heat needed to raise the temperature in your home to the desired level. Two-stage furnaces save money because they can burn less fuel. Thus, they are considered ‘more efficient.’
Multi-stage or modulating burners go one step further, allowing the furnace to adjust its fuel consumption to one of many levels. These have been a huge innovation in furnaces over the last decade, making them more efficient.
2. Heat Exchangers
The heat exchanger in your furnace causes the heat produced by the burner to be transferred in a usable form to the air that the furnace will circulate throughout your house
Most conventional furnaces have a single heat exchange. The heat exchanger’s efficiency is rated based on the acronym AFUE, which stands for Annual Fuel Utilization Efficiency. A single heat exchanger in a furnace is typically rated as an 80% AFUE. In terms most people can understand, that means 80% of the fuel that is burned is converted to useable heat.
A more efficient furnace will often have a second heat exchanger, capturing the heat lost during the burning process. This additional heat exchange can raise the AFUE to over 90%.
In a central air system, by far the most common in homes here in Michigan, the furnace draws cooler air, either from inside or outside your home, and runs it through the heat exchanger, which is heated by the burner. The resulting warm air is then pushed through a series of ducts and reaches each part of your house through a vent.
What causes the air to flow through this system is the furnace blower. Like the burner heat exchange, blowers come in a variety of different types.
Most common today are multi-speed blowers, which run at several set speeds. Like a household fan, your furnace’s blower might have a low, medium, and high setting. However, because these speeds are locked into a specific setting, your system’s overall efficiency cannot be optimized.
More recently, furnace manufacturers have developed variable-speed blowers that can adjust their speed over a continuous range to match system operating conditions. These speeds are adjusted based on the heating needs within your house.
So there you have it, a quick overview of the 3 main components of your home furnace. Understanding these basic terms can help you maintain the system you have and know what questions to ask if you even need help with your system.
Should you ever require a furnace repair or consider upgrading your house’s heating system to something more efficient, just give us a call at (810) 215-9219 . There is never any charge for a personalized evaluation.