That is an interesting explanation. I won’t summarize other than to say that as someone who might have added UV next hardware cycle, there were several A-Ha moments. Well worth watching.
> It’s possible to have a UV system that does what you want without the downside, but it does cost.
The main downside is that you are introducing a chemistry experiment into your ventilation system.
If you want clean air, then (a) cycle in/outside air at ASHRAE-recommended volumes, and (b) use high-MERV/HEPA filters.
In wildfire zones and in wildfire season you can perhaps add charcoal filters—if your system is designed to handle the pressure/head loss—to get rid of the smoke-y smells.
• Positive pressure maintenance, so that any air leak paths are not introducing outside air pollutants
• HEPA filtration, using two filters in series so I can "cycle through" filters, moving the post-filter to the pre-filter location and using a brand-new post-filter (this is similar to the ISS water filter change procedure, and maximizes expendable filter utilization); by the series-parallel circuit math, this should requires four times the total area of HEPA filter
• pressure drop sensors, so I only need to replace the HEPA filter when necessary
• activated carbon post-filter that lets me to replace only the granules themselves, using bulk activated carbon
• washable screen prefilter, to avoid premature saturation of the HEPA medium with >10 micron particles
• washable electrostatic prefilter, to avoid premature saturation of the HEPA medium with <1.0 micron particles
• HRV/ERV, to avoid unwanted heat and humidity transfer to the outside air
• HRS/ERV Bypass, so I can use "free cooling" / "free heating" to exploit natural temperature differences over the day
• (optional) MERV-13 post-prefilter, to intercept ~95% of PM2.5 and greatly extend the life of the HEPA filter train
Does anyone know of a system that has all these features?
One of the critical points to the video is that in order to prevent bad side effects of UV, a deployment is not only costly on the front end but also costly in ongoing maintenance. In addition to UV, there is also a hazard of high voltage induced ozone.
My overall impression is that it isn’t a technology at a consumer grade maturity.
Some UVC generates Ozone, some do not. Wavelength and spectral Q factor matter.
It’s possible to have a UV system that does what you want without the downside, but it does cost.