Most furnaces have single heat exchangers with 80% efficiency. However, those with a 90% efficiency level or more require a second heat exchanger to function. The chief reason is that heat is sent into the ductwork in these furnaces and not released from the vent. Heat exchangers are crucial parts of your HVAC. Thus, to know how to clean furnace heat exchanger correctly, keep reading.

There are two kinds of heat exchangers. It is crucial to ensure that both the heat exchangers are cleaned well for the furnace to function efficiently and securely each time.

Even a tiny soot build-up or any other toxic particle can create pressure and make your gas furnace function inefficiently. Further, this also puts a lot of stress on the devices and increases your energy bills. For instance, if your furnace has even a 1/16th inch of build-up, then your furnace will operate 25% less efficiently and require more fuel usage.

The HVAC article comprises details you will need to clean furnace heat exchanger properly. Also, there are tips and warning signs to consider before and after cleaning these crucial parts.

How does a furnace heat exchanger function?

Before understanding how to clean HVAC heat exchanger, it’s vital to identify how they work. It assists in precisely knowing the issues and preventing them from arising. Several modern systems utilize heat exchangers for instance, furnaces, ACs and more. And, despite the varied parts a furnace includes, heat exchangers are the more critical parts of these devices.

In other words, a heat exchanger is a part that has several tubes or coils on the inner side of your furnace and operates to heat the air. To get precise knowledge on how heat exchangers work, let’s use a simple example.

Imagine if you purchase a very hot cup of coffee. So, to take a sip and cool your coffee before drinking, you might require a few blows. It is exactly how a heat exchanger functions. As per the instance, the heat exchanger is the hot coffee, and the warmth you are blowing off is the heated air inside your home or space. A heat exchanger utilizes fuel to create heat, and the blower motor sets the air on the heat exchanger and then distributes it in the ducts. Fresh high-efficiency devices also have a secondary heat exchanger specifically designed to reduce fuel consumption and give accurate outcomes.

How to Clean Furnace Heat Exchanger?

Yearly cleaning of any heat exchanger aids the entire heating system and assists it in smooth functioning. The average cost of cleaning may come in between 200 to 300 dollars because cleaning both kinds of heat exchangers may take several hours. However, cleaning them is a must as it helps maintain your machines and save on other additional costs.

Today every high-efficiency furnace has both heat exchangers. Thus, to clean the furnace heat exchanger, take the assistance of these steps:

  1. To begin, always ensure you shift the power by setting the breaker off. Further, also ensure to turn the gas and valves off for maximum safety.
  2. Get rid of any dirt or mold present on the insides of the heat exchangers with a wired brush. 
  3. Also, try to loosen black soot or scale if you locate any from every compartment in the heat exchangers. Using a soft damp fabric is the finest option for cleaning gas furnaces, as they help remove build-up easily.
  4. Utilizing a robust vacuum and cleaning the whole block assembly. Then attach the tiny vacuum attachment to remove the debris you loosened in the chamber earlier.
  5. Now, put the breaker on to source the energy to your furnace. Next, turn gas or propane on again.

Tips to Clean Furnace Heat Exchanger Perfectly

Getting the most out of your devices during winters can be difficult. Also, if your devices are not functioning properly, then recognize it’s time to get regular maintenance done. Doing so will help it perform well and give you perfect outcomes. Also, important tasks must only be done by licensed and expert technicians. Further, there are specific cleanings that you can conduct by yourself to save on some cash. One such precaution is to clean the heat exchanger tube well. Use these simple and instant tips to check how to complete it with simple steps.

  • Always Switch the Burner or Gas Off

In no situation must you touch the interior parts of your furnace while the power is still on. If you are not sure how to switch off the energy or gas, then you must contact an expert for maximum safety.

  • Reach the Access Panel

After you switch off the energy or gas, take the help of a screwdriver or your hands to unscrew the bolts holding the panel in place. After you open it, take a torch to access bright light, take a picture, and save it from knowing how the things are placed in the compartment. Now take a tape and label every connection properly to attach the heat exchangers properly.

  • Remove All Debris and Dust Heat Exchanger

Take a vacuum cleaner and get rid of all stubborn webs, mold, build-ups, and other pollutants that might have gathered inside. After this, utilize a wet fabric using a mild detergent to closely clean the pipes and tubes leading to the heat exchanger. It will assist you in removing the exchanger in just some minutes as the device’s exterior is clean and simple to handle. It also assists in preventing debris, mold, or filth from accumulating around you.

  • Clean

Take a pipe brush and a suitable mild cleaner. After this, ensure you clean the inside and every exterior part of the exchanger till it looks smooth and shiny. Ensure you clean every build-up for your heat exchanger to work efficiently. Lastly, wash it well to ensure it runs well with clear water.


By now, knowing how to clean hvac heat exchanger correctly must be quite clear. Use necessary tools and get your work completed with precision. Also, take the right assistance to get accurate results at all times.

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