There are a number of reasons homeowners smell something “off” when running their HVAC. Here we will troubleshoot how to handle some of these HVAC smells without having to spend hundreds on air duct cleaning or other costly repairs.

How to Handle HVAC Smells

Change Air Filters

Dirty air filters can account for some musty HVAC smells so this is a great place to start. Check the HVAC air handling unit’s filter and any other air intake filters you may have in your home.

Air filters should be changed every 3-4 months. If it has been longer than that, change it and see if it helps with the smell.

Confirm Air Flow Direction

Keep in mind, air filters are directional. This means they are intended to allow the air through in one particular direction. This is usually indicated with an arrow. Be sure to install the air filter correctly or the filter itself can cause a blockage and cause stagnant air flow.

If you use disposable air filters, it helps to write the date you changed the air filter on the side of it for future reference.

Clean Water Drain Lines

By looking down into the condensation drain line which is typically made of PVC piping, you can see if there is good drainage. If there is not, you may see a buildup of water causing some mold to grow.

Drano, bleach or another similar cleaning product can be poured into the drain line followed by some warm water to clean and rinse the piping, allowing it to begin draining again.

Evaporator Coil Cleaners

Coined “Dirty Sock Syndrome”, some HVAC smells come from mold and bacteria on the indoor evaporator coil.

To clean the evaporator coil, you can purchase an evaporator coil cleaner and spray it on all exposed surfaces of the coil, carefully following instructions on the can. This can also be done by spraying a 50/50 solution of bleach and water directly on the buildup on the evaporator coil.

Install UV Light

Having a UV light installed in your HVAC system can kill the bacteria, mold and mildew that grow on the wet coils. This should be done by an HVAC professional and will extend the life of your air conditioner by preventing microorganism overgrowth and preventing the system from working harder than it should have to.

This is a starting point for finding the source of HVAC smells. If these tips do not eliminate the smells, call an HVAC professional for a system inspection.

For concerns or additional questions about smells in your HVAC system, or for other heating and air conditioning needs, contact us at Pilchuck Heating.