Of course the ideal method is to have the UVC light internal to your air conditioner/heater unit, which is already circulating the air, so you can blast everything passing through that with enough UVC to annihilate any and all pathogens in the air, but that requires retro-fitting to AC units and stuff.
To get equivalent protection this way you’d need to cycle your air through your HVAC much faster than you likely currently do. Which would be noisy!
And if you’re cycling the air much faster then you need much more UV in the duct to get enough exposure time. And then you have to maintain the lamps inside a dusty vent...has its uses but it’s operationally tricky and there are tradeoffs.
To get equivalent protection this way you’d need to cycle your air through your HVAC much faster than you likely currently do. Which would be noisy!
And if you’re cycling the air much faster then you need much more UV in the duct to get enough exposure time. And then you have to maintain the lamps inside a dusty vent...has its uses but it’s operationally tricky and there are tradeoffs.