The Non-Maintenance Cost of Gas Furnaces

February 1st, 2010

I have been in the HVAC business for nearly 20 years and it still amazes me how many people simply can’t be bothered to maintain their gas furnace. What seems like a common sense chore with real consequences for not doing it, seems a waste of time to some and a waste of money to some. We’re talking health, heat and lives here if a system malfunctions. Carbon monoxide poisoning, global warming and bad air are all results of a malfunctioning furnace.

I’ll give you an example. I visited a home in Naples last year on a no heat call. That’s a call where the customer rings in complaining the furnace isn’t producing heat when they want it to, it’s a standard type call in colder months. The aging population need their heat when the temperature drops.

I went to the house, greeted the customer and went straight to the thermostat. I turned it right up and went to the furnace. No action going on there, so I checked the filters. It was completely clogged with dust and didn’t look like it had been checked in years. How it had lasted that long I do not know.

I changed the filter then rechecked the furnace. The limit switch was wide open, so I had to change that too. Fortunately I had spares with me so I could change it there and then. I replaced the limit switch and guess what? The furnace fired up straight away.

However, there were rollout flames which had to be addressed because the filter was dirty and airflow was restricted. The soot buildup in the exchanger caused a pressure problem where the blower just made things worse. Rollout is where flames escape from the front and washes over the control area. This happens because the usual path of the flame inside the exchanger is blocked by soot, which is made up of unburned fuel and dust in the air.

This whole problem would have been completely preventable with a regular filter check. Rollout can be a significant problem, it can either burn out the controls or escape in the worst situations. The gas furnace was in an enclosed space, inside a closet, which made it difficult to break the unit down and clean it out.

That job took me four hours, some filters, a limit switch and a polite lecture about the benefits of regular filter maintenance. While these kinds of things make my living, I don’t want to read about deaths from carbon monoxide poisoning or fire from a faulty furnace.

Now that’s a real life example of why you clean your filters. That visit cost my customer a little over $200, which is good value if I do say so myself, however, it could all have been prevented if they have checked their filters. It costs much less than that, and will burn less gas when it does work. You can make the money back in a little while by having to spend less on fuel.