What Are The Benefits of UV Light in HVAC Systems? (2024 Guide)

Wonder if installing an HVAC UV light is really worth it?

Overall, the biggest benefit is that ultraviolet light can kill mold, mildew, and viruses.

In this guide, I will go over...

  • The benefit of mold prevention
  • How UV lights can minimize odors
  • And how they improve HVAC efficiency

Let's get started with this guide!

hvac uv light benefits

What Are The Benefits of HVAC UV Lights?

As a home inspector, I have realized that HVAC UV lights are the first line of defense against nasty mold contamination throughout the home. When mold, mildew, and algae takes hold in your central HVAC system, harmful microbial particles can get spread throughout the home to its unwitting occupants.

And I have seen a number of home sales drop through because of gross mold growth.

There are three main HVAC UV light  benefits.  The first and biggest benefit is that it can prevent mold, mildew, and algae growth inside your interior air handler (or furnace). In addition, it can inactivate viruses which help prevent the spread of disease.

The other two major benefits is that it can optimize your HVAC performance and boost efficiency — and help remove any musty home odors (old house smell).

If you want to hear more details on these major benefits of HVAC UV lights, keep reading...

Read Also: What Are The Best UV Lights For HVAC Systems?

#1. Kills Mold & Microbes

Hands down, the number one benefit of installing a UV light is that it will prevent mold growth, stop mildew, kill algae, and even inactivate viruses. Basically, a properly designed ultraviolet light in your HVAC system will keep your air cleaner, so that harmful pathogens don't get circulated around your home.

As a home inspector, I discover mold growth in HVAC systems probably 1 out of every 7 homes — albeit all of my homes are in the humid north eastern United States.

Mold just needs three things to grow and thrive...

  • Darkness 

Your furnace or A/C is a dark place devoid of light.

  • Moisture 

A significant amount of water (condensate) is produced by air conditioners as well as high efficiency furnaces.

  • Food Source

The main food source for mold in HVAC systems is dust, which is mainly human skin cells and furniture/clothing fibers or lint.

If you do see visible mold in your furnace or A/C (just take off the cover and look with a flashlight) it's important that you first clean the visible mold.

If you install a UV light before cleaning visible mold, the mold will die, but it will turn into a harmful mold dust that can get spread throughout your home.

In addition to mold (and in light of the current global situation) it's important to note that there is research on how UV-C light can inactivate influenza and many other pathogens. It mainly does this by disrupting the cells DNA, which damages how it synthesizes proteins and other things. Basically, with damaged DNA, the virus or mold particle cannot reproduce, and it speedily dies.

Read Also: How To Install An HVAC UV Light?

hvac uv light benefits (1)

#2. HVAC Efficiency

In my view, the second largest benefit to a HVAC UV light installation is that it can increase your systems efficiency and performance.

The biggest place where efficiency is impacted with the growth of microbes is the evaporator coil. This is the serpentine cooling coil also known as the A-coil that usually sits above a home's furnace. The refrigerant coil is connected to the exterior A/C condenser, and this coil gets very cold, removing heat and cooling the air for the rest of the home.

If you have a heat pump, this evaporator coil is also used as part of your heating system—the refrigerant just flows in the opposite direction.

Anyways, this evaporator coil has a very large surface area, which is what makes it so effective in removing heat from the air. But since there is such a large surface area, harmful biofilms (communities of microbes such as mold, mildew, and algae) can build up on the coil—greatly reducing its efficiency.

When you keep your coils free of biofilm buildup, it can substantially improve air flow over the coil (preventing a pressure drop) and lowers the energy demands to move the air through the coil. Biofilms reduce efficiency because it disrupts the heat transfer capacity of the evaporator coil.

And if there is mold growth or biofilms growing on the ductwork, the blower fan, and elsewhere inside the HVAC system, they can also contribute to reduced air flow and reduced performance.

Basically, anything that reduces air flow will reduce your systems performance.

Read Also: What Are The Best Honeywell UV Lights For The HVAC?

#3. Odor Removal

My last top benefit for HVAC UV lights is that they can help remove or reduce odors in your home.

Many times when I go into an old home, there is a musty smell in the air. Usually, this strong smell is from mold and mildew growing in their HVAC system or furnace.

Most people don't ever inspect the inside of their furnace, so they never connect the fact that their musty home smell is coming from a central source: their furnace.

And since the UV light will kill and prevent mold, bacteria, and viruses — these microorganisms won't reach critical mass where they release musty odor molecules into the air stream. These musty smells can also contain allergens that contribute to respiratory problems or allergies.

Read Also: Does UV Light Really Kill Mold?

Final Thoughts

Personally, as a home inspector, I think the benefits vastly outweigh the negatives. I would be remiss however if I did not mention a few downsides.

Some HVAC UV lights such as the high quality OdorStop UV lights (with air flow sensors) can get pricey, and you will also have to replace the bulbs every 1-3 years depending on the unit.

In addition, some surface coil UV lights may damage plastic components of the furnace such as electrical wiring, the drip pan, and other plastic parts. In order to minimize damage, you can wrap any exposed plastic parts with foil tape.

With all of the HVAC systems I have seen contaminated with mold, HVAC UV lights are really the only long term solution to prevent mold growth.

And in addition to killing mold and viruses, HVAC UV lights will also make your system run much more efficiently because it reduces biofilms on the evaporator coil.

Meet Your Home Inspector Secrets Author

Ask Me A Question! Or Leave A Comment...

join the 'save my home' newsletter

Get a weekly email every Tuesday with a single home maintenance tip to save, protect, and improve your house!