Diagnose Your Family’s Air Conditioning Problems Over the Phone with These Tips

Once your relatives find out you attend an HVAC school, all their air conditioning problems become yours. Your relatives might even expect you to solve their HVAC problems via a telephone call.

Luckily, many HVAC problems your relatives will call about will fall into similar categories. When your great-aunt Marge calls about her broken air conditioning, work through this guide to give her an accurate over-the-phone diagnosis.

Complaint #1: My Air Conditioning Won’t Turn On

This vague complaint might seem impossible to solve without examining the system, but the problem may be simpler than your relative makes it seem.

First, ask your relative a few basic questions:

  • Have you noticed any anomalies in your electric bill?
  • Do you know how to program your thermostat?
  • Is the air conditioner receiving power?
  • Is the thermostat set to “cooling”?
  • Do you have similar problems with your heater?
  • Do you hear any strange noises after you try to turn on the system?

These questions should help you determine whether the issue is due to human error, a broken thermostat, or more severe causes.

Of course, as a budding HVAC technician, you know that some issues are best handled in person by a professional. Once you determine the cause, you can decide whether you can explain how to fix the problem, or whether your family member needs assistance from a local HVAC technician.

Complaint #2: My Air Conditioning Is Making a Weird Noise

If a relative calls you to ask about a noisy air conditioner, first ascertain where the noise originates and what the noise sounds like.

Outdoor A/C Unit

  • Buzzing: A buzzing noise around the motor may suggest a bad connection or a burned contractor.
  • Humming: If the motor tries to start but is unable to do so, it will often make a humming sound.
  • Bubbling: A bubbling sound is indicative of a refrigerant leak.
  • Banging: A banging noise suggests two different problems. If the noise is more toward the outside, a faulty mount might be the problem. If the noise comes from the inside, the ducts may have a few issues.


  • Rattling/squealing: Rattling or squealing often indicates a bad fan or blower.
  • Popping/whistling/hissing: Any of these noises might come from the contraction and expansion of the ductwork.

Air Handlers

  • Clicking: Clicking noises are often indicative of debris near the fan blades. A broken thermostat can also cause a clicking noise as it makes the relays trip on and off.
  • Buzzing: As an A/C unit’s electrical components wear out, they might start producing a buzzing noise.
  • Hissing: Leaky refrigerant lines sometimes cause hissing noises.

If you are comfortable doing so, walk your family member through minor repairs over the phone. If you aren’t completely confident in your ability to instruct or your relative’s ability to follow, counsel them to call in a professional who can look at the problem in person.

Complaint #3: My Air Conditioner Smells Strange

No one likes an odd odor hanging around their home. A concerned relative might call you and expect you to identify the problem with very little information. Encourage your relative to describe the smell so you can provide further instructions.

It Smells Like Mildew

If your relative calls about a strange smell, it’s probably a moldy, mildew odor. Several factors might cause mold to start growing in an air conditioning system. A dirty filter or an inadequate drainage system are two of the more likely causes.

A/C systems cool your home and remove excess moisture from the air as well. If the moisture collects in an area instead of draining out of the system, mold can easily start to grow. Additionally, dirty filters help the mildew scent to spread throughout the home.

It Smells Like Feet

If an air conditioner is not regularly cleaned, it may clog and the stagnant water will cause a smell like stinky feet.

It Smells Like Sewage

If a backed-up or ruptured sewer line is close to the duct system, methane gas may be able to seep into the ducts. Once the methane gas is in, the smell can easily spread throughout the entire house. This can be very dangerous. Instruct your relative to call an HVAC technician immediately if they smell sewage.

It Smells Like Skunk

While it’s possible that a skunk could make its way into the duct system, it’s more likely that methyl mercaptan gas leaked into the ducts. Methyl mercaptan smells similar to skunk spray and can be quite dangerous. Advise your family member to leave the house and call their gas company and an HVAC technician.

It Smells Like Rotten Eggs

A rotten egg smell is indicative of a dead animal stuck in the vents. Small animals often make ducts their home during the winter. After they die and start decomposing, a rotten egg smell will start to work its way around the house.

It Smells Like Exhaust Fumes

Although air conditioning systems run on electricity, the engine has fluids that can leak out and cause exhaust fumes to seep throughout the home. If your relative’s home smells like exhaust fumes, they’ll need the engine to their A/C unit fixed.

It Smells Like Gunpowder

If your family member’s home smells like gunpowder right after it cycles on, their fan motor or circuit board probably shorted out. This will require a professional to replace old parts.

Once you start your HVAC education, be prepared to become the family’s HVAC guru. Make sure you choose a school that will help you feel prepared to face anything from a dirty filter to a complete system overhaul.