The bulb in the Honeywell UV-Aire stopped working years ago. (Yeah yeah I know it should be changed every year).
This one was $130 at Menards. The furnace company quoted $1200 for their installation of a specialty brand.
The new ones are a double 9". The old 18" single bulbs are NLA from the Honeywell. There are aftermarket ones made in the USA available for ~$25 (vs $50 for the new style at the box store) but reviews indicate many not working, and I'm not sure about the output quality. I've got to do further research.
According to instructions, the new style is rated for return side before the air cleaner, or (as shown) the hot supply side which keeps mold off the A/C coils. That is my limited knowledge. Considering the 1" of insulation this reduces the penetration to 8" and might not illuminate everything. The hole was slightly oblong so I created a circle with five layers of metal tape which should be strong enough for the felt seal. There were vent openings in back of the unit needing the 1/16" air gap, so a ring of silicone was out of the question and I didn't have a hole saw for adding a plate.
The box was lacking data on bulb wattage and cord length (but thankfully it was also 5').
It did not mention needing a metal hole saw or longer phillips bit.
That big handle looks like it was meant to be cranked on. It's not. I added my own marks.
I don't know if the old unit ballast is burnt out or not, but I will try some aftermarkets and stick that into the return for double bulb coverage.
