Lennox Teaches How to Be the Sherlock Holmes of HVAC

August 19, 2020

By: Lennox Learning Solutions Trainers

You don’t need to wear a deerstalker hat, smoke a calabash pipe or even carry a magnifying glass to be an HVAC Sherlock Holmes like sleuth. Identifying and diagnosing system problems are elementary when you spot clues, and know the cause.

Here are five clues to look for during homeowner service visits.

Clue: Dark spots on door hinges

It may appear like a cosmetic problem but this strange clue can be an HVAC system’s call for help. These dark spots happen when an overtaxed HVAC system pulls air around the edges of closed doors in an effort to move the right amount of air through the system. As the air drags past oily hinges, it spreads the oil and any trapped dust along the edge of the hinges. Poor airflow can stress the air handler, blower motor or heat exchanger ultimately damaging equipment, and if the heat exchanger cracks, a carbon monoxide leak can occur. Installing additional air returns and advising homeowners to leave interior doors open can correct the problem.

Clue: Water droplets on windows

Condensation can mean the system isn’t controlling humidity properly. High humidity can lead to organic growth behind sheetrock in the home, which compromises air quality. The solution is to ensure that the system is the right size for the space. A too-powerful oversized system can cool a space without running long enough to remove humidity from the air.

Clue: Clogged air filters

A quick glance will clue you into how often air filters are changed and how well they work. You can ask the homeowner how often they change their filters. If the answer is “never,” you can suggest upgrading to a filter that captures more particles for better indoor air quality (IAQ) without restricting airflow between maintenance visits.

Clue: Allergy symptoms

It’s always good to ask if anyone in the home suffers from allergies. Look for clues like portable air filters and tissue boxes. Allergy sufferers may be interested in learning about upgraded filtration and IAQ equipment to make their home more comfortable and allergy free.

Clue: Freon refrigerant leaks around AC unit

Moisture leaking anywhere in or around your HVAC system is a problem. In the most serious cases, this indicates a refrigerant leak. Freon is poisonous, so call a pro immediately. In less serious cases, it may be water because the tube that disposes of condensation is blocked or broken. This can manifest a couple of ways. Sometimes, you’ll see water leaking out of the unit onto your floor, and other times you may notice ice inside your HVAC on the copper refrigerant lines that run outside the condenser. Both are a sign that a pro needs to look at the situation.

Put your Sherlock Holmes instincts to the test next time a homeowner calls you to check out a problem. Take time to show homeowners the HVAC culprits and explain how they are causing problems so you can offer products or services that can remedy the situation. Learn more at