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24VAC Electronic Ballast for Germicidal UV Light for HVAC Purification

HVAC UVC Air Purification

Residential HVAC units are a natural place for UV-C air purifiers. With direct access to an entire building’s air, these in-duct HVAC UVC units are capable of protecting the entire residence from all kinds of harmful airborne pathogens without taking up an inch of floor space. The residential UV air purifier for hvac industry and product offerings have seen a massive boom since the start of the COVID-19 pandemic, and momentum isn’t slowing.

UVC ballasts specifically designed for residential air purification systems are becoming a necessity. A UV air purifier for hvac device within a residential setting typically has a ballast that can be powered as a standalone device or it can be integrated, by a certified electrician, into the home’s existing HVAC controller, typically run on a 24VAC system. A UVC ballast is designed to operate special germicidal HVAC UVC lamps to their fullest potential. These germicidal UV light for hvac systems are often hidden inside the HVAC system, to prevent any occupants from looking directly at the harmful germ-killing UVC light. Residential HVAC UVC systems are becoming a vital part of our home lives and will continue to be used in homes around world.

Discover a Solution

  • 24VAC Ballast with Integrated UVC Lamp Socket

    24VAC Ballast with Integrated UVC Lamp Socket

  • Electronic Ballast for HVAC Purification UV Germicidal Lamps

    24VAC Ballast with Integrated UVC Lamp Socket

  • HVAC UVC Germicidal Lamps

    HVAC UVC Germicidal Lamps


One of our customers manufactures products for air and water purification via the use of germicidal lamps. We were asked to design a uvc ballast that would power 425mA UV-C lamps in residential HVAC systems. The integration needed to be simplified so it could be installed by the end consumer instead of by a licensed electrician, like previous ballasts required. They wanted a simple, plug-and-play solution.


The customer wanted us to build a ballast that would be wired directly to a residential HVAC air handler, 24VAC electrical system. The ballast was to be installed by the average consumer. The germicidal lamp our ballast was operating needed to survive at least 10,000 on/off cycles.

The system is designed to turn on and off with the air handler within a the HVAC system. The difficulty with such a system is the harsh start up conditions that the germicidal lamp is subjected to along with the frequency, being tied into the air handlers duty cycle.

An air handler within an HVAC system can go on and off 30 or more times per day. That means that the UV lamp, similar to a fluorescent lamp, needed to have a pre-heat startign cycle and reach a strike voltage every time the lamp was lit. If this is done without considering the life of the bulb, the bulb could die after 1,000 starts.

In order for the customer to get a full replacement warranty from the bulb manufacturer, the bulb manufacturer required the bulb to survive 10,000 on/off cycles.


ISL collaborated with the customer’s lamp manufacturer to design this ballast. This ballast features a Programmed Start feature which allows the lamp to start up and last over the 10,000 cycles without lamp burnout. We also designed a custom housing with an integrated lamp socket so that the ballast could be installed directly into the UVC air purifier, without any additional wiring. It’s a simple, plug and play design that simplifies the installation process making it a true DIY project for any homeowner.

Once the design was complete and cycle testing was finished, ISL submitted the product through the safety agency for UL and cUL certification.


Samples of a similar ballast can be found at DigiKey: