Where To Install UV Light On Furnace?

Are you interested in knowing where to install an ultraviolet (UV) light inside your furnace? You are in the right place! Whether you’re just looking for information or want to install it by yourself, we’ve researched the answers to share with you.

It’s best to install a UV light on the air handler of the furnace, specifically at the air handler's evaporator coil. This is because the air handler serves as the passageway for all of the air in an HVAC system, and the evaporator coils are susceptible to microbial growth. 

In this article, we will discuss the location of the installation as well as how to get it done. Continue reading as we delve into further details about UV lights, the pros and cons, and more.

UV light membrane, Where To Install UV Light On Furnace?

What Is UV Light?

It is electromagnetic radiation with a shorter wavelength than visible light. Sunlight contains UV radiation, which makes up around 10% of the sun's overall electromagnetic radiation output which causes sunburns on people.Ultra violet lamps

Sterilization of the areas it comes into touch with is one of the advantages of short-wave UV radiation. As for HVAC UV lights, the bulbs that emit UV light kill airborne viruses, mold, and mildew.

Where To Install UV Light On Furnace?

It will be far less successful at preventing mold or mildew growth if the germicidal UV lamp is mounted in the incorrect location. 

The ideal place to install a UV light is typically the air handler of your furnace. It is the perfect place because it will be the conduit through which all of the air in an HVAC system will pass. 

Specifically, you should install it near the evaporator coil of the air handler, because the evaporator coil is prone to the development of biofilms, which are microbial populations that adhere to one another on a surface. A typical evaporator coil has a surface area of 5,000 square feet.

Fluorescent lamps inside a room

According to specialists, HVAC pollutants typically originate in the evaporator coil (and drip pan). That is why the UV light treatment is commonly installed there, because the evaporator coil gets the most of the light.

The evaporator coil is a portion of the air handler with the copper (or aluminum) tubing through which the refrigerant flows. It often takes the shape of the following:

  • A-Shaped Coils: If an A-shape is being used, the top, center, and downstream of the coil are the optimum places to attach a UV lamp. This makes it possible for the UV light to illuminate the coil with the greatest intensity while also eradicating certain airborne bacteria.

Below the evaporator coil is the second-best spot (if there is room). You can attach the UV furnace lamp to either side of the coil if none of these locations is practical.

  • N-Shaped Coils: There are only two possibilities if the evaporator coil has this shape. The light can be mounted either above or below the coil. Installing the UV light where there will be more moisture and closer to the drip pan is preferable.

How To Install The UV Light?

A fluorescent lamp

Below are the steps for installing the UV lights on your furnace:

1. Choose The Location For Installing UV Lights

Choosing where to install the UV lamp is arguably the most crucial step. It should be placed where it will be most efficient at eradicating mold and mildew.

2. Make The Necessary Hole(s) For The UV Light

Drilling the holes in the metal HVAC cover so that the UV light bulb may be attached is the most difficult physical procedure. Most holes will have a diameter of 1½  to 2½ inches.

3. Attach The Germicidal UV Light To The Furnace Using Screws.

In this phase, screws are used to attach the UV light housing to the furnace. Avoid over-tightening the screws to avoid breaking the plastic casing.

4. Power On The UV Light System

You should give the UV light power once it has been secured. The UV lamp is typically plugged directly into a standard 120-volt socket, which is the simplest option.

5. Replacing And Cleaning The UV Light Bulb

The only major care required after installation is replacing the bulbs annually (or at most every two years) and cleaning the lights seasonally.

A video from YouTube is shown below to show you the actual installation of UV light.

UV Lights On HVAC: Pros & Cons

Below are the lists of benefits and drawbacks of the UV lights:


  • Does using UV lights make the quality of the air better? Yes, if the device is placed correctly, the appropriate wavelength of UV radiation will kill a variety of microbes.
  • UV lights aid in the elimination of mold and mildew. Deep inside the HVAC unit, certain lights have been placed deliberately. A UV lamp will assist in keeping such "vulnerable" locations clean by preventing the growth of this material.
  • Odors are eliminated by UV lighting. Chemicals that cause odors can be found in volatile organic compounds (VOCs). UV lights can remove VOCs from the ventilation system and the air you breathe. 

Tobacco, cleaning products,  paints, and other things not only have a strong scent but also contribute to a variety of health concerns, ranging from headaches to throat irritation.

  • Your HVAC system works better when exposed to UV radiation. Coils and the air that circulates through the system will be naturally cleaned by the UV lamps. 

A cleaner HVAC system also translates to cheaper energy expenditures. As a result, the unit's capacity will be restored by up to 35%.


  • A UV lamp won't help someone in your home with allergies because it can't get rid of dust and dead fungi.
  • For germicidal control, only a few wavelengths can be used. Not all manufacturers can be trusted. 

If the UV light is less than 200 nm, it can produce ground-level ozone. You can tell if the system is producing ozone when the smell of an HVAC UV light makes you think of metal or an electric spark.

Tip: UV-C is the most potent germicidal agent. With a wavelength of between 280 and 200 nanometers, this is shortwave light.

Click here to see this UV-C light on Amazon.

  • Direct UV-C light exposure is dangerous, especially for the skin and eyes. This is not really a disadvantage, but the worry of being exposed to UV light can cause some people to change their minds. 

You or your technician must be able to place the lamp in such a way that no UV light ever hits the eyes of the individuals living in the house.

  • Investing in UV lighting is unquestionably wise. Although UV lights can save you money on the upkeep of the real HVAC system, the maintenance of the lamps may run you a small fortune. 

As a result, you would have to spend a lot of money on both the lamps and the installation. The costs connected with UV lights will be covered in more detail below.

  • UV lamps can harm some HVAC system components if they are installed improperly. Plastics in the air handler that are not UV-stabilized could be ruined by the UV lamps. Therefore, one of the things to consider is photodegradation.

How Much Will UV Lamp Installation In Your HVAC Cost?

Ultra violet light

Experts estimate that installing HVAC UV lights can cost anywhere between $160 to $1,000. But it depends on the factors covered below, which can impact your final cost:

Wavelength Of UV Light

UV exists within the light spectrum at wavelengths between 100 to 400 nanometers (nm). However, only a small portion of that spectrum (wavelengths from 220 to 290 nm) sterilizes DNA microbial contamination.

The strongest wavelength for microbial sterilization in the UV-C range is 253.7 nm. Be aware that any germicidal light causes "secondary emissions." In other words, at the crucial 253.7-nm wavelength, no HVAC UV light can produce 100% of its light energy.

Therefore, make sure that when you select an HVAC UV light it generates light with a wavelength of 253.7nm and at least 80% to 90% of the system's energy, because it will cost more than the system if it is lower than 253.7 wavelengths. The system is essentially a waste of money if it doesn't match those two criteria, so bear that in mind.

Type of UV light 

HVAC UV lamps come in two types. They are air-sterilizing and coil-sterilizing lights. The first one is more expensive than the latter, because the air-sterilizing bulbs produce a greater amount of energy at the 253.7 wavelengths and have higher wattages.  


A UV light system normally costs more if it offers more features. HVAC UV light systems may provide extra features such as wireless remote, LED status displays, auto-sensing smart ballasts, sight glass, and odor production unit.

Pro vs DIY Installation

Your HVAC UV light installation will cost more overall if you have it done by an expert. But beware, if you attempt a DIY UV lamp installation, you run the danger of ultimately losing a lot more money.

Why? In order to properly position and size a UV light in your HVAC system, you must have full knowledge of both the operation of the HVAC system and UV-C light. 

Your HVAC system, particularly the evaporator coil, could suffer damage if the UV light is not placed or sized correctly, and it could even stop functioning altogether.

Another reason to stay away from DIY installation? The manufacturer may automatically void the UV light's warranty if it is not installed by a qualified HVAC specialist.

Wrapping Up

UV light membrane

Installing a UV light has several advantages, mainly to eradicate mold, mildew, and airborne viruses. Before installing, remember that the ideal place to install a UV light is typically at the evaporator coil of the air handler in your furnace.

It is the ideal location because it will serve as the passageway for all of the air in an HVAC system and most of the microbes develop there. 

Before you leave, be sure to check out the related posts below.

Types Of Furnaces And Furnace Filters

How To Clean An Electric Furnace

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