Does Your Gas Furnace Need a Yearly Inspection?


A few common questions about annual HVAC maintenance include:

Is having an HVAC professional come to service our furnace once a year really necessary?


What do the HVAC guys actually do to the furnace to ‘tune’ it up? There’s no spark plugs to replace like a car tune-up, and they basically vacuum out dust and inspect it. Can’t I just do this myself?

These are great questions worthy of a post all on their own. Here are some of our thoughts:

Are annual furnace inspections really necessary?

Furnace manufacturers all recommend annual inspections and maintenance by a qualified technician. They also have language in their warranties saying that damage to the units caused by improper maintenance is not covered under the warranty. Does this mean that an annual furnace checkup is really required or the warranty will be voided? Probably not, but it’s recommended. The best analogy is going to the dentist every six months for a checkup and cleaning; probably not always necessary, but highly recommended.

Some HVAC contractors recommend getting newer furnaces checked every other year, but once they’re more than 10 years old, have them checked annually.

What do HVAC technicians actually do to the furnace to “tune” it up?

It depends. Typically each company has a set of inspection points that aligns with the type and brand of unit getting serviced. Additionally, because there is no “standard” service procedure, every HVAC puts a different name on services provided. A few services you may have heard of are safety check, certification, checkup, tune-up, basic tune-up, seasonal start-up, complete tune-up and annual maintenance checkup.

There seems to be no industry standard for a furnace (or boiler) tune-up, so what’s included in a “tune-up” will vary greatly from company to company. If you’re going to hire a heating contractor to do a tune-up on your furnace, ask them what they’ll be doing. Included below is a partial list of generic stuff that different furnace manufacturers recommend be performed annually by a qualified heating technician:

  • The vent system needs to be checked for blockage and/or leakage. This includes the outside termination and the connections at and internal to the furnace.
  • Combustion gases must be analyzed and compared to the unit specifications.
  • The blower access door needs to be checked to make sure it makes a tight seal at the furnace.
  • The fresh air intake grills and louvers need to be checked for blockage.
  • The heat exchanger needs to be inspected for rust and corrosion.
  • The burners need to be checked for proper ignition, burner flame, and flame sense.
  • The drainage system needs to be checked for blockage and/or leakage. This includes the hoses internal to the furnace. The condensate drain and trap need to be cleaned, and the water replaced in the trap.
  • The blower wheel needs to be checked for debris and cleaned if necessary (this may require complete removal of the blower wheel).
  • An amp-draw test should be conducted on the blower motor and compared with what is listed.
  • The wiring needs to be checked for corrosion and damage – including thermostat connections.
  • Check humidifier connections and make sure water/drain system is operational.
  • The filters need to be checked and/or replaced (but this needs to be done much more frequently than annually).

In addition to this list, heating contractors say that they regularly do static air pressure checks, gas pressure testing, and temperature rise checks.

Could the homeowner do this?

Typically, the only homeowners who are knowledgeable enough to do all the tasks listed above also happen to be heating contractors. If the only thing your furnace tech does is stick a vacuum nozzle into the furnace and suck a little dust out, sure, do it yourself. If your furnace tech does half the stuff on the list above, it makes sense to use them.

Before you hire a company to do a tune-up on your furnace, ask what’s included. The company doing the work should be able to quickly rattle off a list of items they’ll be checking.

Do I really need to pay a professional to do it?

In short, yes. For most heating contractors, the annual service maintenance charge barely covers the trip charge. It’s important to get  a set of eyes on your furnace or air conditioner to immediately address safety concerns, but the real value in a professional furnace inspection is preventive maintenance. It’s about sometimes catching a problem before your furnace quits working in the middle of the night. When you have to hire a heating contractor to show up on a Sunday evening because the furnace stopped working, you’re probably going to end up paying emergency rates, or, even worse, you could be dealing with premature failure of a unit due to neglect.


Pharo Heating & Cooling is a full-service HVAC contractor in Madison. Our team provides top quality service for new construction and replacement furnace and air conditioner needs. For more information about annual furnace inspection or concerns, give us a call at 608-849-5410 or submit a contact form through our website.


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