Roman mythology speaks of twin brothers, Romulus and Remus. Both got along well with each other until a dispute arose over how high the walls surrounding their city should be built. Remus jeered his brother and mockingly leapt over them to prove that they were too low. It cost Remus his life at the hand of his brother, Romulus, who consequently named the city after himself.

The same battle is beginning to plague home inspectors and HVAC service technicians. Both have gotten along well, but the issue of heat exchanger safety has built a low wall in between them, creating a stumbling block of home heating safety issues.


Safety has become a prominent issue for the everyday HVAC customer. According to an article inUSA Today,most potentially dangerous household situations are not obvious to the untrained eye. A cracked heat exchanger, which causes carbon monoxide (CO) to leak into the house, is among those hazards often missed during professional evaluations.

As a member of the HVAC industry, it is important to understand what can be expected from a home inspector. Often, home inspectors let consumers know upfront that they are not responsible to detect certain faults within the home.

One home inspector left the following comment on a national association Web page: “You’ve got to cover your ass on anything you can’t see. I’ve got a disclaimer in my report that states … ‘If you have a gas furnace, a professional tuning and cleaning every year is a good idea. Electric furnaces should be professionally inspected every two years, and for oil furnaces it’s a good idea to schedule a tuning every year. I highly recommend that you request an HVAC technician to inspect the heat exchanger for cracks, holes, or leaks as my inspection is mechanically limited since the furnace requires dismantling to examine this particular area.”

Unfortunately, there are other inspectors who aren’t as educated in heating safety. One home inspector offered his idea of home safety with the following testament to his cracked heat exchanger misgivings:

“A cracked heat exchanger is bad, but they have been known to run a long time without health problems - I know because I ran a cracked heat exchanger for two years. Yes, I monitored the air in the house very close. Here is the deal - the blower tries to blow air into the crack, keeping the gases from getting into the house. Where the problem starts to get bad is when the blower starts to blow the exhaust out the combustible air intake. The bad news is that one has got to keep the stack vent in very good condition.”

Another home inspection professional summed up his opinion in one statement, expressing his concern for customer safety: “Inspecting heat exchangers is outside the scope of inspection because it is outside the scope of view. Detecting heat exchanger cracks requires total dismantling of the furnace system and is difficult at best for even experienced HVAC technicians.”

The relational gap between home inspectors and HVAC technicians, however, surfaces when he continued, “It is common for HVAC contractors to fuel these issues when they indicate ‘your inspector should have found this,’ but they actually have no clue what a home inspector does.”


Barring some confusion, most home inspectors are honest and straightforward. If it is out of sight, then it is primarily out of mind, and that makes getting the heat exchanger checked the homeowner’s responsibility. Homeowners don’t seem to mind this until they run into a situation such as this one.

While selling their home, a couple had a home inspector report that their furnace had a cracked heat exchanger; they had it checked by a heating contractor and the gas company. Neither found any cracks or any other problems. The inspector insisted that the furnace was unsafe, and the buyers looking to purchase the home were unwilling to complete the purchase unless the heater was replaced.

This happens more often than reported. The confusion caused by multiple tests and different diagnoses left the customer unsure and wary of the home inspector and the HVAC technician.

Adding to the trouble are some home inspectors’ opinions of HVAC technicians.

“HVAC contractors are required to red tag any furnace that is a potential safety issue,” said an inspector. “However, HVAC technicians have been known to go overboard to sell some new equipment, especially when dealing with a piece of equipment as old as this. Some of them just don’t want to fix it.”

Some home inspectors, however, understand the importance of HVAC service technicians. “Home inspectors, however, need to realize their own limitations also, and not pretend they are self-proclaimed heating experts, unless they are licensed or qualified to do so,” commented one home inspector.


On the other side of the wall is the HVAC service technician. Many technicians argue as to what constitutes a red tagged or unsafe furnace. Dealing with customers can be difficult at times, but when it comes to red tagging a system, when customers hear conflicting messages from multiple HVAC technicians and home inspectors, the problem is only compounded. One customer relayed his confusion via a community chat Website on the Internet.

After having a service technician in to look at his furnace, this man wrote, “Do you think this [water testing] is a worthwhile diagnostic test that correlates with real safety issues, or just a great way to sell new furnaces and make this guy rich giving seminars for companies so willing to have him teach techs to find leaks in a three-year old heat exchanger?”

He went on to further explain that the technician came to give his 15-year-old furnace its annual cleaning, and having learned a new diagnostic technique, he pulled the heat exchanger, ran a water test on it, and found a crack. “This furnace had a visual inspection and tested CO free on all chambers less than a year ago,” said the customer. “What is the likelihood that my current furnace really has a safety concern?”

One contractor on the Website replied, “Could be fine. Maybe, maybe not.”

Another listed multiple reasons why he thought the test was irrelevant. “I thought combustion chambers were supposed to run dry. Isn’t adding a bunch of water a hazard?” he said. “If a service technician is getting zero monoxide, why are you continuing to test? Are you trying to find something wrong with it?”

The final service technician let the previous service tech know just how wrong he was about relying solely on CO readings for confirmed heat exchanger safety.

“Once again you prove your complete lack of knowledge in the HVAC industry,” said the technician. “You do know that you can have a heat exchanger with a hole in it big enough to put both of your fists through and still not register any CO reading, don’t you? So, would you let that customer continue to run their fossil fuel appliance with that large of a hole in it because it was registering a zero CO read? You really shouldn’t be allowed anywhere near customers’ appliances. You are scary and dangerous.”


Trying to clear up some of these inspection misgivings, multiple tests and methods have been developed to look for cracked heat exchangers. Visual inspections must be combined with other methods to confirm that there is or is not a crack in the heat exchanger. Depending on the type of heat exchanger, it is possible to miss up to 80 percent of cracks in the unit due to exchanger design and accessibility. When using a CO reading, it is imperative to remember that this number should be used to confirm a condemned furnace, not to prove that a unit is safe.

According to the Air-Conditioning and Refrigeration Institute (ARI) textbook, “If a leak is suspected in a heat exchanger, you must completely disassemble the heat exchanger, if necessary, to confirm that there is or is not a leak. Never allow a possibly leaking heat exchanger to remain in service.”

“If in doubt, change it out,” said Larry Jeffus, author and HVACR consultant.


Education is the solution to this dangerous heat exchanger puzzle and volatile home inspector, HVAC technician relationship. Service technicians must spend time investigating and understanding what is and is not safe. They should also be aware of what home inspectors actually inspect. Home inspectors should watch for visible, tell tale signals, document them carefully, and advise customers to seek the assistance of a professional HVAC technician.

What does a functional and healthy home inspector and HVAC service technician relationship look like? Here is an example, found at the earlier referenced home inspector national association Web page, of an actual home inspector and service technician working to solve a potential hazard and provide safe home heating.

“I [the home inspector] inspected a furnace and later received a call from the owner that this furnace had been ‘red tagged’ due to a cracked heat exchanger. Previously, I had inspected the furnace as thoroughly as I knew possible. In my report, I stated that the furnace was old and that we are unable to determine the life remaining. The problem is that the homeowner claimed that I should cover the cost to replace the furnace. The owner has since contacted a reputable HVAC technician. The technician installed a new furnace right away, and told the client that I did all I can and that there was no way of determining when the furnace would fail. The clients then contacted their real estate agent and told him that they should have read the signals and replaced the furnace upon moving in, and that in fact, the report indicated that the furnace was old.”

Working together is important for both industries’ images, and customer safety. Instead of fighting each other over a low wall, the home inspector and the HVAC technician accomplished customer safety and satisfaction without damaging anyone’s reputation.

Not all home inspectors are oblivious, and not all HVAC contractors are out to make a fast buck. It is about time the two set some standards and play like a team. Who knows, it might just save someone’s life.

Publication date:03/05/2007