Keeping the Inside of your Air Handler and Furnace Clean (updated 2019)

A clean air handler can maximize the life span of your equipment, and also prevent allergies and air flow problems. There are many reasons why your air handler could be gather debris, dirt or even mold, so let me cover some of these so everyone can have a better idea of what is going on inside of your air handler.

4 Reasons Why the Inside of your Furnace Gets Nasty While Cooling your Home

Can this be prevented? Bacteria growth recycling through the air in my home? Not really, but it can be slowed down by keeping your filters changed regularly. Higher the MERV rating on the filter, the more it will help keeping your air handler clean.

Air filter quality helps, such as those purple ones sold at your Home Depot or Lowes do a wonderful job of keeping the air clean, and the inside of your air handler, but they also put stress on your blower motor and may reduce air flow depending on what type of motor you have.

Insides of furnaces turn bad. Regular preventative maintenance and cleaning of the evaporator coils can ensure your system stays in top shape.

  Really though, this is a direct effect on dirty evaporator coils. Although all condensate drain pans inside of your air handler will grow bacteria eventually, even with a HVAC U/V light installed.

Happy bacteria can create a small pond in your HVAC condensate drain pan. It will start off as a small town and expand in population, which can lead to clogged up condensation lines. Which in some cases may be why your air conditioner isn’t cooling.

And if your blower wheel is dirty, then more than likely so is the rest of the air handler and insulation. If your evaporator coils are dirty then this can also lead to a dirty blower wheel. Another big cause is air leakage in the air handler.

Now many of the newer split residential systems these days are under negative pressure up to the blower wheel compartment, meaning if there are any air leaks at the air handler it is going to be constantly sucking in dust, dirt, debris, mold spores and whatever else might be in the air. If you have electric heat and your blower wheel is dirty then more than likely your heater elements are dirty, and so are all of the connections and wires.

Dust will accumulate on your electric heating elements. This can cause a burning smell or worse depending on how often the electric heater is used.

 Location depends, but working in Florida for as long as I have, I’ve seen many split air conditioner systems that just have undersized duct work. If your airflow is poor and duct work undersized, there may be more condensation taking place in your air handler than it’s designed for. The blower wheel may be pulling excess condensation off of the evaporator coils pulling it into the rest of the air handler, rusting out electrical components and creating mildew within the system. Especially if you are in a hot humid environment, such as Florida.

Environments that are humid, don’t get along well with bad insulation either. Some older homes have attics that are poorly insulated compared to modern standards. Same thing with the duct work, yes these are insulated, but more than likely that air handler is going to sweat condensation, which can lead to micro-bacterial growth.

Bottom Line: How to Keep the Inside of your Furnace Clean

• Make sure your HVAC system is properly sized, by a professional HVAC company
• Get professional HVAC maintenance done twice a year
• the Higher MERV rating on your air filtration, the cleaner your furnace, generally speaking

Recommend combination air filtration. For example, PureAir makes some great filtration kits such as the Lennox Y6608 – Healthy Climate PureAir 612988-01 Annual Maintenance Kit for PCO3-20-16  which uses a MERV 16 filter along with UV lights.