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Comment by germinalphrase | Hacker News Reader

Do you use the carbon scrubbers in-line with your HVAC or did you rig of some kind of stand alone system?

Stand-alone. I got two cylindrical carbon filters and one fan. I slide the three components together and then stand them up vertically like a floor standing speaker.

Currently living in an apartment. It scrubs the air really quite fast. Helps a lot with kitchen smoke, pet smells, cleaning chemical vapors, and new furniture/plastic VOCs.

I also live in the middle of a bunch of chemical plants so it’s invaluable for the 3-5 leak events we experience every week.

One of our cats has learned how to turn our HPA300 fan to “turbo mode” by bopping the correct button with his paw. This year he’s been an excellent early warning system for nearby chemical plant leaks and I’ve learned to blindly trust his judgment so I just turn the scrubber fan to 100% whenever the cat turns up our largest HEPA air filter.

I recognize this sounds insane.

That is the damndest thing

Please indicate the correct kind of cat to complete the BOM for this system.

My BOM:

- $199: TerraBloom 6" Silenced EC Inline Duct Fan, ECMF-150-S, 288 CFM, 36W

- $114: TERRABLOOM 6" AIR FILTER 24" LONG, 1.8" (46MM) THICK,

- $80: TERRABLOOM 6" AIR FILTER 16" LONG, 1.8" (46MM) THICK

- $3,000 (2022 prices): Siberian cat. Bought before recent price rises where the prices have apparently more than doubled, somewhat killing my dream of getting another Siberian kitten. Closely related to Maine Coon and Norwegian Forest Cat. Very very very playful and social. Enjoys playing friendly games of tackle with my Texas Heeler dog (50% Australian Cattle Dog, 50% Australian Shepherd), and often can be found entertaining itself throughout the day by training my dog. Naturally played fetch with plastic water bottle caps from a young age. Wants lots, and lots, and lots, of cuddles and play time. Our other Siberian, which was imported from Russia by American breeders, has had a very rough life and joined us late in her life. She has a very similar natural temperament. All three shed a truly totally insane amount of fur -- recommend Miele vacuums which are fully sealed with proper gaskets for maximum suction and minimum allergen leaking/spreading...Dyson strongly not recommended. He has had a lifelong fascination with dissecting electromechanical objects, especially air filters, and insists to supervise/assist with all maintenance work going on in the home. He learned that biting apple cables causes humans to stop using the laptop and destroyed $1,000 of laptop chargers when first generation MagSafe charges had non-detachable cables. Unlike his older sister, he has never had interest in killing/murdering animals, but enjoys removing all the legs from cockroaches and then playing fetch with himself by throwing the body around. Announces most of his poops with a loud meow and insists that the litter box be maintained daily. Enjoys training the humans, especially enjoys training the dog to get the humans to perform desired behaviors on his behalf. Contrary to marketing materials, neither Siberian is actually "hypoallergenic" in any sense of the word...maybe they're "less" allergenic but they still cause a lot of allergies and sheets/pillowcases need to be changed often.

I'd probably go 8" if I was buying today, I hedged a bit cheaper because I wasn't sure if the quality/performance would be what I needed.

This made my week

> recommend Miele vacuums which are fully sealed with proper gaskets for maximum suction and minimum allergen leaking/spreading...Dyson strongly not recommended

Have you tried a water vaccuum? :)

Is that a vacuum cleaner that can suck water, or are there vacuums that use water to clean the exhaust like scrubbers on ships do?

Probably works like a water pipe aka bong

To sibling comment: bongs cool down smoke, not filter it

If they only cooled it down, the water wouldn't be so incredibly disgusting

I tested this in college, they definitely also filter it. Just not very well. But 3+ chamber bubblers do filter fairly well.

Still, if you’re looking for that, edibles and temperature-controlled vaporizers are way to go.

There is actually, it’s called Rainbow Vacuum. They used to (maybe still do?) sell them door to door MLM style but the vacuum is actually good in my experience with them.

My mother has one of these, but I didn't know its name until now! I actually remember the salesman coming to our home and showing us how it works. It's still going strong ~25 years later. I'm currently using a Miele something, but I'm always a little weirded out by the fact I have to change vacuum bags, because when I grew up we would just flush the dust down the toilet after vacuuming.

Now that I know what my mother's vacuum is called I'm a little tempted to get one myself...

Funny thing as it pertains to this thread is the Rainbow salesmen used to sell an air freshener or early essential oil to add to the water. I can recall the smell perfectly now

This is like poetry. First comment I've "favourited" on HN that isn't explaining some deeply technical thing I want to reference later

Thanks for sharing your air filter setup. How large is the space you’re filtering with your setup and how many months do the Terrabloom filters last before you have to change them? Also where’s the HEPA component of the system? (Agree about Miele vacuums with a HEPA filter insert, which is supposed to be changed annually. Mieles also last forever with minor maintenance).

700 sq. Ft. So far 9 months with the terrabloom and no noticeable degradation of filtration. HEPA provided by 7 other filters, mostly Coways. Those need filters changed every 2 months.

Agree with Miele ease of maintenance, though they immediately stopped providing OEM parts (belts) for the uprights the day they discontinued them. They still sell the expensive bags for them though.

What size did you get and what size is your apartment? Just looked up Terrabloom and I want these yesterday.

I would personally get the silenced fans in the largest diameter you can afford / fits in your desired space because it will move larger amounts of air more quietly. The apartment was 700 sq. ft. I got the silenced 6" and it's reasonably quiet at most speeds, and not that loud at the highest speed -- putting filters at both intake and outlet greatly reduced the noise vs. just one side.

If you get the filters and fans in the same diameter they will just slip together without any additional hardware. But it will be quite wobbly. I used velcro (monoprice, laying around for wire-taming) to secure it to a vertical bookshelf.

My BOM: - $199: TerraBloom 6" Silenced EC Inline Duct Fan, ECMF-150-S, 288 CFM, 36W

- $114: TERRABLOOM 6" AIR FILTER 24" LONG, 1.8" (46MM) THICK,

- $80: TERRABLOOM 6" AIR FILTER 16" LONG, 1.8" (46MM) THICK

I'd probably go 8" if I was buying today, I hedged a bit cheaper because I wasn't sure if the quality/performance would be what I needed. This has been running for 9 months now with almost no noticeable degradation in performance, although I'm not currently quantifying it. Eventually I intend to install 3 VOC sensors, one outside the unit near the intake, one inside the unit, and one outside the unit at the outlet....to measure the VOC scrubbing efficiency curve over time and assist in deciding when to replace the carbon.

We've been running it 24 hours per day, usually about 40% but sometimes at the lowest setting (maybe 25%) and sometimes at the highest 100% setting.

After 9 months, it can still use it for point sources of concentrated smells like soldering and it captures 100% of the odors. And this is operating in a high-VOC environment near a lot (dozens) of chemical plants on our side of the city.

I've been running a similar setup next to my litter box for about 2 years using "Vivosun" products, which seem like a cheaper knockoff version of Terrabloom.

The Terrabloom stuff looks higher quality and I can't compare it directly to Vivosun, but I've got no complaints about my Vivosun duct fan or carbon filters. I'm not necessarily suggesting one brand over the other, but just to add that you can run a knockoff version of this setup for a lower cost.

I’m trying to picture the systems. They’re basically a carbon filter sandwiched by two fans, it runs the air through the filter and puts it back in the room? Or is it connected to a vent that exhausts the air outside (or does it filter one coming outside air?)

In my case, a fan sandwiched by two filters. Recirculates through room so filtration will follow the differential equation models for “CSTR’s”, which are Constantly Stirred Tank Reactors.

Which Vivosun products do you use and how large is your space? Is there a HEPA filter in the system, or only carbon?

Love coming to HN and learning from the in-depth research of others on topics like these.

How important do you think the external fan is? (versus just placing it next to the modest airflow of a HEPA filter, as a sibling commenter suggested)

Very important. “Non-ducted” suction doesn’t have enough static pressure to pull air through a carbon filter, will pull the air around it instead. In electrical terms, this would be like feeding a power sink with a large gauge copper wire and a medium resistance resistor in parallel. 0.01% of the electricity will pull through the resistor, 99.9% will come through the bare copper wire.

the one major downside you'll find to terrabloom is how often you have to replace the carbon filters, but that's just true of carbon air filtering in general.

> I recognize this sounds insane.

The insane thing is not your cat - cats are damn smart if they want to. The insane thing is that leak events happen multiple times a week and nothing seems to happen, or that residential zoning is right next to heavy industry in the first place. WTF?

Agreed. See https://news.ycombinator.com/item?id=33427667 for a detailed explanation.

I also constantly rant about the zoning thing. Even if you believe people should be allowed to live where they want, there should be more information provided to help dramatically lower the price of that housing but the apartments cost about the same as apartments in cleaner parts of the city 60 miles away.

I think I'm going to try this. A little concerned about the wobbly-ness of the vertical stack of all of these given the weight of the filters. Seems like all these systems are intended to be ceiling mounted to grow tents. Wish there was a nice metal frame that could be used to floor-mount this setup a little more elegantly.

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