Air purifier?

[WussRedXLi]

I bought Sharp KC-A50E in the end. I have been wondering, the suction of the air is at the back of the machine. Most people, I believe, will place the air purifier against the wall. If they do so, the suction will be facing the wall. Then why are all the indicators located at the front? What a weird design... Shouldn't the suction face outward towards the room?

Back/front all will work, no worries. The difference in cleaning efficiency is very negligible.

Leave a 3" gap.

 

[lala81]

Ignore the idiot.

 

[WussRedXLi]

Office filtration by the HVAC's AHU is good!!! I think they using at least a solid F9.
Externally is 30000+ for 0.3 microns. Out on the streets it's 20-25ug/m3. I tested in open air kopitiam, 9-11ug/m3. NEA reading (1-hr average) is approx 10-15 ug/m3. Excellent.

10am 12 μg/m³ (PSI 50 / AQI 50) 15 μg/m³ (PSI 53 / AQI 57) 12 μg/m³ (PSI 50 / AQI 50) 14 μg/m³ (PSI 52 / AQI 55) 2 μg/m³ (PSI 8 / AQI 8)

This is why 2013's PSI 401 people say "can survive", that's simply coz most are holed up in the office. I was out on the streets with a N95at 10+ to 11+ before lunch, trust me i took it off for 1-2 try try min, really kena smoked out bad.

 

[WussRedXLi]

Will test the various Amazon H13 HEPAs (Fellowes HF-230 and Honeywell H filter) and also the taobao filters. Hope the tissue paper stuffing to prevent bypass works. (Testing is for the whole system, not only the HEPA filters)

 

[Akai Ryu]

Any possible way to check if Sharp's plasmacluster is working?

 

[WussRedXLi]

Any possible way to check if Sharp's plasmacluster is working?

Put your ears at the exhaust and switch to lowest fan speed. There should be a zzz, zzzz, zzzz, zzzz sound with definite pauses in between. That's what i am getting on my KC-840, FU-Z31, FU-A28.

 

[WussRedXLi]

Ambient - 15690

Sharp KC-840E with Honeywell H type True HEPA filter. I think there could be some slight leakage, dunno.
0.3 microns = 180. Efficiency = 98.8%

Sharp FU-A28 with Fellowes HF-230 True HEPA filter.
0.3 microns = 0 or 10. 99.93%

Samsung AX40 with Taobao claimed H12 filter
0.3 microns = 330 Efficiency = 97.9%

 

[WussRedXLi]

So as you can see, the airflow figure makes a more significant impact than the HEPA grade. You can compensate for lower grade HEPAs with pure brute force.

Samsung AX40 would reign supreme. Most airflow with least amount of noise and least amount of power consumed.

 

[Roti Prata]

Is it alright to paste a piece of 3M Filtrete at the intake of my air cleaner? I'm thinking this can increase the lifespan of the HEPA

 

[WussRedXLi]

Is it alright to paste a piece of 3M Filtrete at the intake of my air cleaner? I'm thinking this can increase the lifespan of the HEPA

Not really...very expensive. If you buy from that recommended taobao seller and customise the filter size, you will also get a PP microfibre mesh prefilter. It is 5mm thick so you can tear it into half in terms of depth so its just 2.5mm thick to reduce air resistance.

Amazon also sells $0.99 aircon filter. V big in size.

The original Sharp HEPA filter already has this thin prefilter built-in (green in colour) in addition to the 500 micron aircon-type net prefilter.

3M Filterete too expensive.

 

[WussRedXLi]

But seriously you can just vacuum the surface of all those taobao HEPA. The bigger PM is all stuck at the surface. Vacuum fortnightly thr HEPA and also the net prefilter.

 

[xrubiksx]

yeah..its a good idea to use 3M but need more $$ to sustain..probably like what others said..try getting from other stores like tabao..should have cheaper alternatives..haha

 

[Roti Prata]

I just have this random thought, not sure whether did I make the greatest discovery of the century. I have a feeling that the Magiclean Wiper is the same as the 3M Filtrete. They have similar texture and they look the same.

 

[WussRedXLi]

If you'd find a dusty black piece of glass and lightly place that MagicClean wipe on top of it and later you can see a patch of clean black glass, then yes that Magic clean is electrostatically charged and you can use it as a pre filter. But i think it is going to present quite a fair bit of resistance.

 

[chuanz]

Amazon 9210 (no valve) $3.98 not sure price will hold how long.

3M 9210/37021 Particulate Respirator, N95, 20-Pack https://www.amazon.com/dp/B00065UIDS/ref=cm_sw_r_awd_9szUub1ZCCDQG

 

[WussRedXLi]

Interesting discovery

I noticed something with the laser particle counter that I just bought.

I believe most people would gun the air purifier at max speed initially first and then throttle down the speed after a period of time (20 mins? 1hr?). Something like what some would do with the aircon as well.
This is especially the case for noisier ones like the Honeywell 50250 bought from Amazon etc.

Now, the air would be very clean after gunning it. What I noticed is that after throttling it down to low speed, the number of particles in the air rises. Let me give you an example.

Pretty small room with furniture in it, approx. 14 sqm. Samsung AX40 + I brought over the Sharp FU-Z31 from another room to run this test. ie loads of cleaning horsepower


Before : Ambient number of particles, ~ 26,000 particles/L (the 0.3 microns figure on my meter but lets not get too fixated at absolute numbers as it's probably not super accurate)

After gunning it for over 2 hours, ~ 120 particles/L

Switched off the Sharp and switched the Samsung to low speed.
Went to sleep, woke up for toilet break 1hr later and found that the number of particles rose to about 4000 particles/L.
Its not a lot...but i reckon the PM is from the aircon (potential allergens)

The windows are pretty air-tight, coz the sides got rubber gasketing and I found that during a thunderstorm with high winds i'd get howling sounds if I leave a slight gap, close it properly and turn the knob to lock position and there is zero howling. Door still got slight gap though.

I think the airconditioner FCU might have an effect. I do keep my aircon FCU quite clean as I DIY clean every 2-3 months.

 

[WussRedXLi]

What does this mean for the various Air Purifiers?


Switch it on to max for at least 15 mins first, esp during hazy days later on in the year and/or you have airconditioning or your room is dirty and you are stirring up the allergens. Best case is to keep the aircon and bedsheets/floor absolutely spick and span but I know that's usually impossible.

Throttle down to High/Med speed later on. If there is a haze mode, use it as it alternates between Medium and Medium High (not High) speed on my Sharp. This still keeps the airflow up but noise down.


1. Samsung AX40. Only the high speed is usable. Auto speed, low speed, sleep mode speeds are not useful at all. Bummer. But the good news is, it's among the quietest around and even in high speed 323m3/hr, it consumes 34W ...which is like the medium speed of a Sharp A28 doing 100m3/hr only, and both noise levels are the same (the Sharp A28 in high is noticeably noisier than the AX40)

2. Sharp KC series. (eg KC-840, KC-A40, KC-D40) Auto speed and Low speed are of not much use

3. Sharp FU seres (eg FU-A80, FU-A28, FU-Z30 and 31). Auto speed and Low speed are of not much use.

4. Novita NAP101 and NAP501. I think only the High and Turbo speeds are useful. Even the medium seems a bit week, coz I think people buy the NAP501 for big master bedrooms even.

Coz i'm using the Samsung AX40, and it seems that for the past 12 months, whenever I put it into low speed (I wanna save some electricity), I still wake up with some blocked nose. I have been suspecting that the CADR is insufficient but have no prove.
Now I have.

I think simply put is that as long as you are not getting the CADR for more than 2 air changes per hour for that speed that you are using, it's somewhat likely that you are not going to get the required sustained cleaning that is required for your condition.
Eg, allergic rhinitis, sinusitis, asthma to a certain degree. Kids, old folks with heart or lung conditions, or have had operations before.

Normal folks without conditions, doesn't matter that much.

Some people mentioned "what about the office then"? As mentioned before, I have tested in a regular office building with central AHU, there is decent cleaning of the air by the filters used as the air quality is good (in fact by PM2.5 concentration standards, it registered as 0ug/m3.

I think you have heard before people saying that Air Purifiers do not alleviate their condition. I think this is the answer, CADR at the speed setting that you have selected is key.

 

[WussRedXLi]

Amazon 9210 (no valve) $3.98 not sure price will hold how long.

3M 9210/37021 Particulate Respirator, N95, 20-Pack https://www.amazon.com/dp/B00065UIDS/ref=cm_sw_r_awd_9szUub1ZCCDQG

LAst lowest price was usd4.07 for the box.

But I reckon some have issue hitting $125 to get free shipping. Luckily the N95s do qualify for free ship.

 

[Akai Ryu]

Put your ears at the exhaust and switch to lowest fan speed. There should be a zzz, zzzz, zzzz, zzzz sound with definite pauses in between. That's what i am getting on my KC-840, FU-Z31, FU-A28.

Thanks...hope i can hear something and not those frequency that only 'young' ears can hear

 

[WussRedXLi]

Thanks...hope i can hear something and not those frequency that only 'young' ears can hear

No problem one....its middle high freqs.