How to Deal With a Red-Tagged Furnace

Amy Pawlukiewicz
Written by Amy Pawlukiewicz
Updated November 9, 2021
A family warming feet on a radiator
Evgen -

A red tag sale at a department store might give you some serious deals, but a red-tagged furnace means your appliance has a serious problem

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You hired an expert to conduct your bi-annual HVAC inspection, but now your pro tells you that your furnace has been red-tagged. That isn’t exactly a dream scenario, but it’s one that homeowners may have to face. We’ve broken down all the nuts and bolts of red-tagging, including what it means, what causes it, and what to do next.

What Does Red-Tagging Mean?

The red tag designation is assigned by either an HVAC pro or a utility worker, and it means the appliance is not safe to operate in its current condition. Red-tagging can apply to any appliances that require gas for operation, including water heaters, dryers, stoves, and, of course, furnaces. Whichever professional has red-tagged your appliance will shut off the gas to your home until the problem is resolved.

Causes of Red-Tagging

As far as your home’s heating system is concerned, there are a few root causes that will get your furnace red-tagged.

  • Blockages in vents or chimney: Any blockage in your vents or chimney will cause the carbon monoxide (CO) that’s supposed to be released from your system to flow back into your home, which can lead to carbon monoxide poisoning.

  • Cracked vents: Cracked vents render the safety seals on your HVAC system useless, releasing CO into your home.

  • Cracked heat exchanger: The heat exchanger on your furnace is the element that separates the safe hot air from carbon monoxide when the gas is burned. When the exchanger cracks, the hot air and gas can mix together and make their way into your home.

  • Electrical hazards: If you live in an area that frequently experiences flooding or heavy rains, your furnace could get damaged by the water and cause CO to leak into your air.

  • Other problems: There are several other things that can cause your furnace to be red-tagged, including a gas leak caused by built-up pressure and dirt buildup on the heating coils.

Types of Red Tags

There are two types of red tags that a technician can issue: Type A and Type B.

  • Type A: This type of tag represents more severe gas leaks that are an immediate hazard to your health, such as a severe carbon monoxide leak. If there’s a Type A leak, the technician will immediately shut off your gas until the problem is resolved.

  • Type B: These tags indicate that there isn’t an immediate danger to the home’s occupants, but there is an issue that needs to be addressed. With Type B tags, you usually have 30 days to make the necessary repairs.

Repair or Replace a Red-Tagged Furnace?

A technician repairing a furnace
Tomasz Zajda -

The choice between repairing or replacing your furnace depends on a couple of factors. First, check your warranty. A cracked exchanger is a costly replacement, but it may be covered under your furnace’s warranty. If it’s not covered, it may be less expensive to replace the furnace because, in order to repair the exchanger, the entire furnace has to be dismantled by a pro. 

In many cases, the only fix for a red-tagged furnace is to replace the entire unit. If you have to replace your system, you can breathe easier knowing that in addition to being safe, a new furnace will be more energy efficient than an older model and increase your home value.

Get a Second Opinion

If your furnace has been red-tagged, you should get a second opinion from another HVAC professional before moving forward with repairs or a replacement. Get a second look to confirm the accuracy of the first opinion and avoid unnecessary work or expenses.

Cost of Repairing or Replacing a Furnace

If you can’t repair your red-tagged furnace or the repair will cost more than half the price of a new appliance, you probably want to consider investing in a new furnace. Furnace repairs can range from as low as $130 to upwards of $2,000, depending on the issue. 

On the other hand, new units cost between $2,000 and $6,000, including installation, so take that into account when speaking with a pro about repairs.

How to Avoid Red-Tagging

Sometimes, age and use simply wear a heating system down. However, an annual or biannual inspection and cleaning will help keep your HVAC system in its best shape and detect any problems that may be on their way.

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