[mensetmanusman]

UV is more than UV, there is UVA UVB UVC, etc.

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.

[throw0101a]

> 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.

[schiffern]

What I really want is a system that has

• 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?

[adolph]

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.