7 Signs Your Furnace Needs Repair

Furnace repair changing furnace filter


Keeping your furnace in good repair won’t just assure you are ready for the Midwest winter’s worst. It will also save you money on (A) utility bills, and (B) the larger, more expensive repairs that become necessary when smaller problems were ignored. The earlier you detect a problem, the cheaper and easier its solution. That rule applies to many things – furnaces included.

Just because you can’t fully explain how a furnace works doesn’t mean you can’t tell when it needs repair. A malfunctioning furnace gives many obvious hints when it isn’t working properly. Here are seven signs that you may need to contact an HVAC company right away!

1. Increased Heating Bill 

Blower motors, gaskets, burners, flame sensors, and pretty much every other part of a furnace wear down over time. Each part of a heating system plays a vital role. When one starts malfunctioning, the entire furnace’s efficiency suffers for it. That translates to an abnormally high heating bill – a glowing sign your furnace needs repair.

2. Pilot Light Is Yellow

Many appliances have pilot lights. They provide small, constantly burning flames that are always ready to ignite a gas burner. When a pilot light’s own gas flame is blue, it is combusting correctly. But when a pilot light flame burns yellow, pay notice. It may only be because the pilot lighter is burning dust. Otherwise, a yellow (or red) flame could signal that improper combustion is producing potentially deadly amounts of carbon monoxide.

3. Furnace Makes Strange Noises

A furnace should intermittently pop or click, and then proceed to hum gently. That is part of the furnace’s normal and necessary operation. A healthy furnace may also buzz, purr or murmur.

When a furnace makes noises other than those, it may be announcing that something is seriously wrong. A screech could mean a malfunctioning belt. A loose blower wheel makes a scraping sound. The combustion chamber grumbles when it continues burning fuel after the burners have extinguished. If you hear any loud, unusual noise radiating out of your furnace, call a professional who is fluent in the language of furnaces.

4. Furnace Cycles Frequently

Is your furnace cycling on and off way more often than it should? That is probably because it has one of three problems:

  • The thermostat is running low on battery or broken. Alternatively, the thermostat may be installed in a suboptimal location, such as in direct sunlight or adjacent to a heat register.

  • The air vents need cleaning, or the filter needs replacement. Low airflow can also result from a dirty blower wheel, which is more likely to break the longer it goes without cleaning.

  • The flame sensor is dirty, corroded or otherwise malfunctioning. The flame sensor tells the furnace when to close its gas valve. A malfunctioning flame sensor turns off the gas valve during normal operation, thus forcing the furnace to shut down and start back up again.

5. Animal Activity

If given the opportunity, mice and other bothersome rodents are happy to take up residence in HVAC systems. They like the warmth, quietude, and lack of predators (your house cat excluded). If you notice droppings or nesting materials inside your furnace or near its vent hood – or a foul odor emanating from the heating vents – then pests may be interfering with your furnace.

Mice are notorious for gnawing plastic insulation off wires. Unfortunately, there are many important wires inside your furnace cabinet – any of which could become incendiary once a mouse strips it to bare copper. Rodents also frequently build nests within ducts, which obstructs airflow and accelerates wear and tear on the furnace as a result.

6. Furnace Is Old

The average residential furnace’s lifespan usually falls between 15 and 20 years. If you haven’t bought a new furnace since the George H.W. Bush administration, then it probably needs repairs at the very least. Contact a reputable HVAC service and ask for one of their technicians to do an inspection. They may discover a few easy fixes that will significantly improve your furnace’s efficiency, and recommend when a replacement would probably become economical.

7. Furnace Won’t Start

A furnace that simply won’t turn on is clearly in need of immediate attention. The issue may be as simple as a thermostat setting, dirty filter or extinguished pilot light. Once you have ascertained that none of those are the issue, call an HVAC technician. A faulty ignition sensor, leaky gas line, malfunctioning fan or other serious, complicated problem may also prevent your furnace from starting.

Do you need furnace repair in Sioux Falls, SD or the wide surrounding area? Contact PrairieSons today! We diagnose furnace issues almost as quickly as we make them go away.