Skip navigation

Serving Northern California Since 1946

Serving Northern California Since 1946


DeHart Plumbing, Heating, and Air Inc. Blog

The Air Filter on Your AC/Furnace? It’s NOT to Make Your Air Healthier


Air filtration systems are one of the standard ways we can help a home enjoy healthier air free from the majority of large contaminants circulating through the HVAC system. But often when we bring up air filters, homeowners are confused. “But I already have an air filter. It’s in the HVAC cabinet, and I change it every few months with a fresh one. Isn’t that helping with air quality?”

We understand why people are confused about this. The truth is that the air filter on your AC and furnace is not designed to improve indoor air quality. It may have a minor effect on it, but to enjoy tangible benefits to air quality requires having professionals install dedicated air filtration systems in Modesto, CA.

What Does the HVAC Air Filter Do?

If the air filter on the HVAC system isn’t cleaning the air in your house, why is it there? This filter protects the interior of the HVAC system, rather than protecting air quality.

The blower fan in the HVAC cabinet draws air through the return air ducts and then sends it through the AC/furnace to be cooled/heated before it then goes into the supply ducts. However, the air pulled through the return ducts is filled with debris picked up from the house, such as dust, dander, and fiber from carpets and furniture.

These particles are harmful to the AC and furnace: they can cause motors to burn out and restrict heat exchange and heat absorption. Only a small layer of dust allowed into the HVAC cabinet will lower energy efficiency and lead toward repairs. The filter on the cabinet stops this debris from getting inside.

This is an important job (and regular filter changes are necessary to make sure it keeps doing the job) but has a minor impact on the quality of the air in your house. These filters can’t be too thick or the blower wouldn’t be able to draw air into the system.

Dedicated Indoor Air Quality Filtration Systems

The filters your house needs if you have poor indoor air quality are designed specially to trap a wide range of pollutants that can circulate through the air of the house. These filters can be powerful enough to stop bacteria–although for most homes this is too powerful, and the filter will end up blocking airflow as well.

Our professionals can determine what type of air filtration system will do the best job for your house. We’ll make sure the filter’s strength (rated as MERV) won’t hinder airflow or lower comfort through the rooms. If there are still contaminants that are getting through the filters, we can match the filtration system with an air purification system. When we have the right set of IAQ solutions installed, it will remove more than 99% of air pollutants and not harm the working of the AC, furnace, or heat pump.

To find out more about the quality of your home’s air and to schedule IAQ device installation, speak to one of our specialists.

Call Greenhart for air filtration systems that can make your household healthier. Live Green, Save Green!

Comments are closed.