I have worked on such systems at Signify: There are numerous barriers to wider adoption except for very high risk situations. For instance: there have yet to be lawsuits to determine the risk of exposing people to UV. As you see in the comments below, any "UV" is considered dangerous by people not aware of the biological effects of various wavelenghts.

Besides this, excimer lamps have a low expected lifetime, of both the light source as well as the filter due to the high energy in the UV photons. This makes replacement (and maintenance cost) a real risk. This could be remedied by similar wavelength LEDs from companies like CrystalIS but these are expensive and very low power (only work germicidal on a short distance).

Prof. Brenner at Columbia University has first foreseen applications of 222nm in operating rooms, to prevent infection during surgery.

On the whole, it would need significant investment in both research, certification and risk analysis for this to become commercially viable, so while some of the technology is there, the market demand so far just is not -- post-pandemic.

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Llamamoe 4 hours ago | parent | next [-]

Is there any reason why they can't just be installed inside air purifiers/ventilation?

Especially since you could probably get more mileage out of the same amount of light energy by forcing the air through a narrower passage, since only airborne particles are actually going to absorb any energy anyway, and air is mostly just empty air.

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rob74 4 hours ago | parent [-]

That solution is actually suggested in the article. However, that still leaves the cost issue mentioned by GP, and until that is solved, this will remain something for specialized applications (operating rooms) and maybe hypochondriac millionaires...

	▲	harddrivereque an hour ago \| parent [-]
		...and maybe diy germaphobes.. just like positive air pressure ventilation systems. In fact, you could combine

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modeless 6 hours ago | parent | prev | next [-]

Yeah I saw a lamp for this and it had a proximity sensor to prevent overexposure. There's no way I'm buying a lamp that needs that to be safe. Especially if it's expensive and only lasts a year or two.

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unsnap_biceps 6 hours ago | parent | prev | next [-]

Every year our HVAC company tries to sell us UV lights for the HVAC system. They claim it's only about $1500 to install. Are these snake oil?

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orwin 3 hours ago | parent | next [-]

Depends on your HVAC system and the maintenance cost in your area. For me at 150€ per intervention it wouldn't make any sense, but I have heard some HVAC develop a smell and in that case, UV is likely to prevent it.

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stuaxo an hour ago | parent | prev | next [-]

If I had an HVAC system I would absolutely have UV in it, to mitigate sick building syndrome etc.

Can't comment on the price.

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mahrain 6 hours ago | parent | prev [-]

Mostly used to eliminate or reduce mould growth on the inverter? If HVAC is taking air in or blowing air out, there really wouldn't be a point disinfecting the air.

If it's re-circulating, it could reduce the spread of germs room to room as has been shown during the pandemic in elderly care facilities. That would be the only use-case I see.

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unsnap_biceps 6 hours ago | parent [-]

they claim it would reduce growths on the coils but also eliminate mold and bacteria spores. Our system is a re-circulating system. One large intake in the center of the house and out flows in individual rooms.

	▲	mahrain 6 hours ago \| parent [-]
		The mould reduction is real, and could lenghten the maintenance intervals for cleaning. Not fully eliminate it though, it really only eliminates the parts the UV light reaches (so not the back, or any other part not exposed).

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metalman 2 hours ago | parent | prev [-]

there are much simpler and more reliable ways to significantly reduce indoor air contaminents. one is a building method that produces a "floating" slab floor, that has a small gap around most of the walls, and the underfloor space is vented upwards with a chimney, this creates a small but continious air current that removes most dust and other things in the air.

And then the simple expedient of useing radiant heat sources, that while not as lethal as UV, are in fact quite deadly to bacteria and anything tiny with a high water content, but completly harmless to humans and ,animals,plants. Couple this with hard, smooth ,surfaces that are designed so that there no crevices or areas filth can acumulate, useing hard woods,glass,tile,metal,leather/vinyl l,high gloss paint,for surfaces. No cloth, no carpet.While not exactly cosy or friendly, it makes getting home that much nicer. Cheap, reliable, low maintenence, implimentable at scale, now.

	▲	mahrain an hour ago \| parent [-]
		Your first paragraph is advocating for ventilation, which is great but there's been so much incentive to reduce building energy consumption (heating/cooling) that recirculating, filtration and other technologies have resulted in offices becoming almost sealed off. We are now moving towards more balanced models as people don't feel comfortable in such offices e.g. sick building syndrome.