Calgary Heating: The Cause of CO Leaks in Furnaces

Calgary Heating: The Cause of CO Leaks in Furnaces

Hey all, it’s Kyle here and we’re going to talk about something pretty serious. As a furnace repair company, Clearview gets no shortage of inquiries about carbon monoxide poisoning. We’ve discussed what carbon monoxide is and how it affects the body and how it gets into our home, but there is still a lot of misinformation and disputes about how carbon monoxide leaks into homes. Hopefully, we can clear up some of the misconceptions so that you don’t go racing out to buy a new furnace every few years!

Carbon Monoxide Poisoning-How Common is it REALLY?

You’ve probably seen headlines before: THOUSANDS DIE EACH YEAR DUE TO CARBON MONOXIDE!


Pretty scary stuff huh? But in truth, CO poisoning is not that common (if it was, we wouldn’t have gas furnaces anymore!) Roughly 300 people a year die from CO poisoning in North America, though the number of poisoned people coming in for treatments climbs to several thousand a year. Furthermore, not all CO poisoning is due to furnaces; some of it is from incorrectly set up fireplaces, portable generators and from leaving your car running too long in an attached garage.

So, in the grand scheme of things, fatal CO poisoning just isn’t that common. Fatal CO poisoning from a furnace is even less common. Phew!

So What Causes the Furnace to Leak CO?

In the cases where the furnace was to blame, any number of factors come into play. You may have heard that it’s due to a cracked heat exchange. If you have a cracked heat exchange or a hole in, carbon monoxide will leak out and kill everyone. Is this true?

It can be. Certainly damage to any part of your furnace is hazardous and can cause fire, gas leaks, electrical shocks and of course, the furnace will break down entirely. But it’s not the only thing which can cause CO leaks, nor is it the immediate culprit. Some heating companies will try to sell you on the idea that a tiny hole in the heat exchange means that the furnace is compromised and you have to buy a new one; however, this may be nothing more than a scare tactic for a payday. (Sad isn’t it?)

 So what can cause a gas leak?

  • Clogged filters/clogged chimney. Now HERE’S a cause you won’t hear much about because frankly, it’s pretty mundane. However, clogged filters and a lack of ventilation is probably more likely to cause a leak than a hole in the heat exchange. When your filters and chimney are clogged, things like dust, dirt and gas have nowhere to go; they cannot be properly ventilated and so they back up and spew into your home. This causes dirt build up, dust build up and gas leaks.


  • Cracked heat exchange. Yes, this can cause it too (in spite of claims to the contrary from people trying to sell you other stuff… hmmm). The heat exchange is a series of tubes in the furnace which separates the combustable gas from the air that will be circulating around your home. If the heat exchange has large cracks, holds, dents and bangs, this gas can leak into the air and be circulated around your home. This usually happens in old furnaces as the tubing becomes more fragile. However, if you get this diagnosis and you have a relatively new furnace, it might be a good idea to get a second opinion-just in case.
  • Debris, rust and holes and in the pipes going outside. Here’s another one you may not hear of! (damn that heat exchange!) In order to prevent CO build-up, your home has to be well ventilated and this means having proper piping to the outside world. Pipes which are covered in debris, rusty or not connected properly will leak CO.
  • Improper installation of the blower fan. Oy! If your blower fan is blowing air in your home instead of out, you may get a CO build up plus a lawsuit because I at least would sue whoever was dumb enough to install the blower fan the wrong way!

As you can see, the reasons for a furnace leak go far beyond the often touted cracked heat exchange—it’s just that the other reasons don’t sound very scary and don’t make people want to buy stuff.

You should make sure to get your gas powered furnace inspected by a reputable technician once a year or so in order to ensure that everything about it is in good order. You can also use CO alarms near the bedrooms so that if there is a leak, you will be alerted to it and can evacuate before anyone becomes seriously ill or dies. Carbon monoxide poisoning is a serious thing and you don’t want it to happen to you and your loved ones.

Clearview Plumbing and Heating has some of the most experience plumbers and heating technicians in Calgary waiting to help you! Contact us at…


Clearview Plumbing and Heating is a Calgary Plumbing and Heating company based in Calgary, Alberta, Canada which is available round the clock to carry out any type of Calgary Plumbing or Heating job.

You can reach us any time at 403-220-0090.

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Keywords: calgary heating, CO Leaks, Furnaces, Carbon monoxide, furnace repair, misconceptions, common, carbon monoxide poisoning, cause of leaking, hazardous, leakage

By | 2018-05-26T11:36:00+00:00 September 26th, 2012|Carbon Monoxide Testing, ClearView Plumbing & Heating, Heating|