Comment by Sn0wCoder | Hacker News Reader

Comment by Sn0wCoder | Hacker News Reader

Just curious what peoples thoughts are on whole house ionizer’s that attach to the furnace. Just got an inspection and mentioned we recently had our ducts cleaned as our youngest has mild Asthma and I have mild allergies. The duct cleaning has kept our filter super clean over the last 6 months but I asked what else I could do. Long story short got a ionizer on sale but after seeing it installed and it’s relatively small size feeling like it might be kinda scammy. It’s a plasma air air purifier and I looked them up and have good reviews, but without actually testing the air before and after not sure how to prove it does anything. Sorry I know it’s a tad off topic but kinda related since one of the claims is ‘ Plasma Air significantly reduces airborne pollutants commonly found in homes such as bacteria and viruses, mold spores, odors, chemicals from paint, varnish and cleaning agents, volatile organic compounds (VOCs), and even cancer-causing formaldehyde emitted from furniture’. Cheers and thanks for any feedback.

An Investigation of Ozone Emissions From Consumer Products: https://ww2.arb.ca.gov/resources/fact-sheets/ozone-emissions...

Ozone Generators that are Sold as Air Cleaners : https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-...

Ideally, don't use ozone-generating or other gimmicky devices. Ventilate the space instead. Usually, unless there is a high pollution event or it is peak allergy season, the air outside is lower in contaminants than indoor air.

Vacuum frequently using a machine with a HEPA filter and run your home's air circulation system with a MERV13 filter, or get/make an air filter. (https://www.youtube.com/watch?v=aw7fUMhNov8)

If you feel you must use an ozone generating device, don't use it if the spaces are occupied and ventilate them thoroughly before occupying them again.

Definitely don't use them along with other cleaning/deodorizing chemicals, as the result of mixing those with ozone is complex and poorly understood.

Thank you for the info. Man now I second guessing that impulse buy. Going to read up and maybe even have them remove it. Tech was a good salesman and made me feel like I was helping my family, while I might have done the exact opposite. Glad I asked, and glad you took the time to inform me.

The Home Performance YT channel (https://www.youtube.com/c/homeperformance) is a good resource also. It's a couple who have become experts in practical home air quality management.

Get a MERV16 filter for your furnace and you'll have amazingly clean air. https://www.researchgate.net/figure/Mean-PM-25-removal-effic...

The higher the # the more restricted the air flow is, which is harder for the fan to work with. This may be an issue if the fan is not very good.

It is not true though that the air will become amazingly clear based on the presence of the filter. I used a 11 for a long time and it certainly didn't stop everything from getting covered in dust anyway. My place is not airtight.

Everyone says this, but it's not true for the newer filters which use electrostatic attraction to filter the smaller particles.

A dirty filter (do you know how many people don't ever change their filter?) will put far more load on a blower than a better filter.

A MERV11 is significantly less effective, and wouldn't affect dust production anyway since it is created mostly by your skin, clothing fibers, etc.

During the California wildfires I bought several air sensors and placed them around my house and experimented with different filters. a MERV16 with a carbon layer reduced VOCs, PM2.5, etc all down to extremely low levels in every room.

One caveat on this - most residential systems don't have fans that are designed to go up to MERV16.

High MERV ratings put more load on the blower equipment.

The fans aren't "designed" for MERV16, but most are very capable of supporting them. I'm not sure how this misconception got hold that it's significantly bad to use higher grade filters. See my other comment - https://news.ycombinator.com/item?id=33550653

It also produces ozone which is not great to be breathing. UV-C is more effective than plasma but still produces some nontrivial ozone if it's bright enough to be disinfecting air.

Thank you did not do much research just took the techs word as he told me about all the courses he took and how great they are.

I used to sell similar home products -- if it's similar to my experience, those "courses" are given by the manufacturer, and really, they're just tutorials for their dealers on how to sell/install/use the product. They're not academic in nature, but telling the customer you've taken "courses" on the subject makes them feel quite compelled to trust you.

As others have pointed out the issues with ozone generators, I'll just throw ERVs as a ventilation option into the mix. An ERV with a filter can cycle out not just particles, bacteria, and viruses, but also dangerous gases.

Ozone is not good for you or a lot of materials in your house, get a good filter for the intake instead.

A high MERV filter will remove bacteria/viruses as well as a bunch of other stuff.

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