Although the Lennox Health Climate single and dual germicidal lamps run higher than competitor models, I selected their X9425 model (UVC-41W-D model) that is hard-wired into my Lennox 3 ton Air Handler. Atomic Filters had the best price and order processing, shipment and delivery of product was very fast. I ordered it on a Friday afternoon and had it first thing Monday morning. I chose to install the unit myself. I have no formal HVAC training other than reading and carefully following the instructions, watching others and asking questions. There are several YouTube videos and I did locate one where this Lennox product in the single lamp configuration was being installed. If you are a DIY'er, the provided instructions, template and a basic knowledge of hand, power tools and electricity makes for an efficient install. Installation required shutting off the breaker to the air handler, a drill with Unibit to make 1" diameter holes in the Delta plate covering the AC coils and the second hole in the plenum, nut driver or socket wrench and a Phillips screw driver. The cable for the 208V supply gets hard-wired to the line, neutral and ground wires inside the air handler. the installation took under one hour. I've seen where some consumers are looking for the UV light to only be on during AC or FAN operation. That makes sanitization of the surfaces less efficient. the light should remain on, especially to radiant the damp coils and environs to kill and prevent mold growth. This UVC product is combined with a previously installed electronic air precipitator having pre- and post particle filters. Ductwork and house remain free of dust and air smells fresh. I was pleased with the ease of installation, operation and performance and recommend this product. Both of my air handlers have this model installed. Take note, if you are installing in a plenum with branch ducts and it has flex duct connected, UV light and plastic are incompatible. Lennox sells a UV lamp light shield to protect plastic components. On my attic installation, I had a HVAC professional add some 90 degree metal elbows and lengthened the trunk lines with insulated metal duct per the product instruction sheet to protect from UV degradation of the plastic flex duct. Be sure to change the lamp yearly as the germicidal effect of the lamp degrades after about 12 months of continuous operation. Once the lamp illuminates you'll see if there are any unsealed openings along the ductwork light path that need sealing and thus making delivery of conditioned air more efficient.
Had the light installed by a local HVAC company. Was told the install went smoothly and it was a professional grade item. I agreed, the light system appears to be high quality and worth it's price. It's definitely NOT a 29.99 special. Hoping for many years of trouble free service.