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How Do UV Lights for HVAC Units Work?

UV LightThese days, you hear a lot about how over-exposure to UV light can cause sunburns and increase your risk of skin cancer. But, UV light in appropriate doses also has health benefits such as helping individuals' bodies form vitamin D, sterilizing water and surgical equipment, and sterilizing products in the food and drug industries.

Not surprisingly, UV lights are also used in heating and cooling systems to kill mold, mildew, bacteria, and other contaminants. But a shockingly low number of homeowners realize the advantages of adding UV light to their systems.

To get you started, here are two types of UV lights to use in your HVAC system and their benefits.

Types of UV Lights for HVAC

Basically, there are two types of UV lights for HVAC systems.

  • Coil Sterilization. This light is installed above the evaporator (A-coil) in the plenum duct on top of the furnace. It runs continuously, is the most common type used in HVAC systems, is easy to install, and is the least expensive — as low as $200. Shining directly on the coil, this method keeps microbial growth from happening on the coil surfaces and inside the drain pan.
  • Air Sterilization. This UV light sterilizes the air that circulates through your system. It’s installed in the return air duct. It also helps to keep the evaporator clean but not as effectively as shining the UV rays directly on the coil. There’s a range of systems available, so prices can vary.

Benefits of UV Lights in Your HVAC System

Both coil and air sterilization offer ample benefits for you and your family. They include:

Improved Airflow

UV light prevents the build-up of contaminants on air filters, cooling coils, drain pans, and in ductwork. That all contributes to unrestricted airflow, which in turn not only makes your home more comfortable but helps reduce maintenance costs and extend the life of your system.

Health Benefits

UV lights kill mold, mildew, bacteria, and other bio-contaminants before they have a chance to circulate in your home’s air. That means you and your family won’t be breathing in potentially harmful contaminants that can negatively affect your health. The lights can be extremely effective. A study at Duke University Medical Center found that UV lights used in the HVAC system helped reduce bacteria in hospital rooms by more than 97%. While that’s good news for anyone, it’s especially good news for family members who have allergies or other respiratory concerns.

Better Energy Efficiency

Having a clean, efficient system means lower energy usage and costs. Adding UV light to an existing system can significantly reduce energy costs. Industry estimates range from 10%–35% reduction depending on factors like the age and type of system you have.


The cost of an air sterilization UV light is relatively modest. Estimates range from $450-$700 and can vary by state. Other factors include the specific wavelength the light emits, type and features of the system you select, and professional vs. DIY installation. But, given the return on investment — lower energy bills, fewer maintenance calls, longer life of system components, and the health advantages — many homeowners find the initial investment well worth it.

If you’re considering adding UV lights to your system, it’s a good idea to consult with a pro. They can explain all the options available and suggest the best fit for your system. To find a reliable HVAC pro, use our convenient dealer locator.

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