The Most Important Repair Your Furnace May Need!

During the short winter season when you run your gas furnace, your main concern will be that it works the way it should and provides the heat necessary for household comfort. Safety, however, is another concern. We don’t want to be alarmist and make you think the gas furnace in your house is a constant source of potential danger. Modern furnaces are constructed with the uppermost safety in mind, and few furnaces will create any hazards provided they receive routine maintenance inspections from professionals and are repaired promptly when the need arises.

But there is a specific repair issue we want to address—it’s the most important repair your furnace may need because it is a major safety hazard. And that repair is…


The heat exchanger is the component of a furnace that does the actual heating of the air moving into the vents. The combustion gas from the burners can’t be used to directly heat the air, because that would permit harmful gases to enter the air distributed around the house. What happens instead is the hot combustion gas enters a narrow metal container: the heat exchanger.

The heat of the combustion gas transfers to the metal walls of the exchanger and turns them hot. Air from the air handler blows across the hot metal surface of the heat exchanger and the heat transfers to the air. This air continues into the ventilation system to the rooms, while the exhaust gas in the exchange escapes through a flue to the outside of the house.

The potential danger here is the gas in the heat exchanger seeping out and into the air. This can happen if cracks start along the metal surface. Even a small crack can allow harmful gases like carbon monoxide to get into the air because the metal surface of the exchanger expands with the heat, causing the crack to spread open.

The most common cause of these cracks is corrosion on the metal of the exchanger. Years of use or poor ventilation causes a reaction between the metal and the vapor of the combustion gas that lead to corrosion. When corrosion weakens the metal, the stress of the heat exchanger expanding and contracting may create cracks. This puts your household in danger of exposure to harmful gases.

Recognizing the signs

We recommend calling for furnace repair in Buda, TX to replace the heat exchanger if you notice these signs:

  • Clicking noise from the furnace cabinet after the blower fan shuts off.
  • Corrosion appearing on any part of the furnace.
  • The odor of rotten eggs in the house. This is a special chemical put into natural gas so its odor can be detected.
  • Your CO detectors go off. (Vacate the house first and call the gas company before calling for repairs.)

If your furnace is more than 15 years old, it’s at a higher risk of a cracked heat exchanger, and we recommend an inspection to see if it’s ready to be retired. If your furnace is this old, then replacing the heat exchanger is not a cost-effective choice; it’s better to have a new furnace installed.

The intelligent choice today makes sense tomorrow! Call iAir Services for furnace repair in the Greater Austin Area.