Furnaces don’t come with expiration dates, so it can be difficult to determine when yours needs replacing. They do, however, provide a few telltale signs that their end is near. If you’ve noticed any of the symptoms below, then it’s time to invest in a new furnace or seek out a A&A Mechanical for certified technicians who have been serving Bucks or Montgomery counties for more than 30 years.


First consider the age of your furnace. On average, the lifespan of a well-maintained unit is between 15 and 20 years. The older a furnace gets, the more maintenance it will need. Depending on the cost of regular maintenance, and taking into consideration larger repairs in the future, it may be more cost-effective to replace your furnace sooner rather than later.

Increased Heating Bill

An older furnace works increasingly harder to provide the same levels of heating it did when it was new. A slight increase in costs as it ages is okay, but significant increases in your home heating bill could be an indication of costly furnace repairs to come. A short-term investment now could save you a lot more later on.

Cold Air

It may seem obvious, but a furnace that’s circulating cold air is a warning of furnace failure. It could be a number of things including: a problem with the motor in the blower fan, heat exchanger or pilot light. If you’re experiencing any of these issues, contact one of our HVAC technicians to see what the next steps are.

Loud, Strange Noises

Furnaces will make some noise when turning on and off, but if those noises keep getting louder it may be an indication that your unit needs some work.

  • Rattling may signal unsecured duct work or an unbalanced motor.
  • A slight humming comes from the fan motor, but it should never be loud or disturbing. If it is, your motor may be failing.
  • Screeching occurs when there is an issue with the blower motor or inducer motor, like a loose bearing or an old belt that needs replacing.

Yellow Pilot Light

The pilot light in a natural gas furnace should ALWAYS be blue. A yellow pilot light means that your furnace is in need of immediate attention and could be leaking carbon monoxide, which is a poisonous gas. If you find a yellow pilot light or notice a rotten egg odor, shut off your furnace and call a technician immediately.


If you notice an unusual amount of dust – particularly around the heat registers – your furnace may be trying to tell you something. Your furnace takes in air from the outside, filters it, and heats it before releasing the air into your home. The older your furnace gets, the more difficult it is to filter the air as effectively.

If you’ve experienced any of the above symptoms, call A&A Mechanical today at 215-396-1525. Our certified HVAC technicians will examine your furnace and help you make the best decision to meet your family’ heating needs.