Your heating, ventilation and air conditioning system helps warm your space during chilly Michigan winters and cool it when summer rolls in. Much of the credit goes to the heat exchangers in your furnace and air conditioner, which absorb and move heat between locations. Learn more about the heat exchanger heating and cooling process and maintenance tips to ensure your HVAC system works safely and efficiently.
How Heat Exchanger Heating Works
A heat exchanger in a furnace is a series of metal coils or tubes that conduct heat. It functions based on the principle that heat moves naturally from higher temperature areas to cooler ones.
Here’s how a furnace heat exchanger works:
- The furnace burns fuel in the combustion chamber, generating heat in the form of gases.
- The combustion gases move into the heat exchanger, warming the metal.
- Heat from the metal warms the cool indoor air surrounding the heat exchanger.
- The warmed air flows into your home’s ventilation and circulates throughout your home or business.
- Combustion gases, including carbon monoxide, are vented outside your home.
Primary And Secondary Furnace Heat Exchangers
A furnace may have one or two heat exchangers, depending on whether it’s a high-efficiency system. Furnaces with a low AFUE rating are less efficient and have only a primary heat exchanger. In this system, hot combustion gases move through the primary heat exchanger, into a flue and out of the building.
Furnaces that are more than 90% efficient are equipped with secondary heat exchangers that capture additional heat. In these systems, gases that are otherwise vented are moved into a secondary heat exchanger. The gases cool slightly, forming water vapor and creating latent energy. The secondary heat exchanger uses this extra energy to warm your home’s air, increasing the furnace’s efficiency.
Air Conditioners and Heat Exchangers
Air conditioners use a similar principle to cool your space, but the heat exchanger heating process works in reverse. An air conditioner uses two sets of metal coils: evaporator coils filled with a refrigerant that absorb heat and condenser coils that release heat.
Here’s how heat exchange works in an air conditioner:
- The air conditioner pulls in hot indoor air, which circulates over the coils.
- The liquid refrigerant inside the coils absorbs heat.
- The cooler air is returned to the room.
- As the refrigerant is warmed, it turns into a low-pressure gas that travels to condenser coils.
- The condenser coils release the heat and the cooled refrigerant returns to liquid form.
- The cooling cycle begins again.
The Importance of Heat Exchanger Maintenance
Heat exchangers are hard-working components of your HVAC system, helping regulate indoor temperatures during Detroit’s sweltering summers and brisk winters. But you need regular HVAC maintenance to ensure they’re working properly. A cracked furnace heat exchanger can cause dangerous gases to leak into your ducts or create fire hazards. Dirt may accumulate on an air conditioner’s coils, impacting performance.
By scheduling an annual fall heating tune-up or spring air conditioning maintenance visit, you help ensure the heat exchanger and other parts of your HVAC are in optimal condition. An HVAC professional can advise on the cost of a replacement heat exchanger if needed or let you know if it’s time to replace your furnace or air conditioner.
