15 minutes ago, ThaiBrian said:

So the 3M is electrostatic? So somehow the PM 2.5 is attracted and it attaches to the material? Like other skeptics, I don't believe its very efficient. I would be surprised if 1/4 of all the air that passes through is filtered. 

Simple to prove, get a meter, I have - it works ???? 

52 minutes ago, ThaiBrian said:

I just bought a 1,000THB Chinese copy of a high quality air purifier and just bought a couple of HEPA Filters. It can move a lot of air as well. 

And the plastic will likely burn like hell if fan overheats.  Had cheap black hole type MQ trap and that was exactly what happened.  Low cost plastic and items than can overheat them are not good partners or items to have in your home.

3 hours ago, CGW said:

Simple to prove, get a meter, I have - it works ???? 

 

My results.  The meter is sensitive to around 0.3 microns, and is sensitive + able to respond to cigarette smoke (narrowband particulate size, can go google the size).  But in a very small room of about 8 sqm  (9000 btu/hr FCU).   With that said, it is usually not a good idea to cover up the FCU intakes to such a degree....but this is just for testing.

 

Of course, a HEPA air purifier would have much higher CADR.

 

As it gets dirtier and dirtier, the filtration efficiency goes down drastically.  Relatively speaking, HEPA does not have this issue, but of coz its lifespan is not indefinite.

 

1 hour ago, vivid said:

8 sqm is like the size of a small bathroom. The air must of passed through 100x in 20 minutes. What enables the capture of these tiny particulates? I'm looking at a <deleted> now and there are tons of holes/gaps in the filter. Does it first need a thin layer of dust to then block the tiny 2.5 pm? Glad it works tho. My air purifier does have a pm readout but I don't trust it. 

 

 

My results.  The meter is sensitive to around 0.3 microns, and is sensitive + able to respond to cigarette smoke (narrowband particulate size, can go google the size).  But in a very small room of about 8 sqm  (9000 btu/hr FCU).   With that said, it is usually not a good idea to cover up the FCU intakes to such a degree....but this is just for testing.

 

Of course, a HEPA air purifier would have much higher CADR.

 

As it gets dirtier and dirtier, the filtration efficiency goes down drastically.  Relatively speaking, HEPA does not have this issue, but of coz its lifespan is not indefinite.

 

 

1 hour ago, ThaiBrian said:

8 sqm is like the size of a small bathroom. The air must of passed through 100x in 20 minutes. What enables the capture of these tiny particulates? I'm looking at a <deleted> now and there are tons of holes/gaps in the filter. Does it first need a thin layer of dust to then block the tiny 2.5 pm? Glad it works tho. My air purifier does have a pm readout but I don't trust it. 

 

Yes, my 2 bedrooms are extremely small.  3.4 x 2.5m.  The masterbedroom is bigger at around 16 sqm.

 

The 3M N95, N99, N100 masks are also electrostatic filters, and if you open them up the holes are definitely bigger than 2.5 microns.  But they are very effective to even 0.3 microns.  These media work by attracting the particulates like in an electrostatic precipitator.

 

You can also read up on how HEPA works.  They also do not work solely like how a sieve does.

 

The Filtrete greatly restricts airflow as someone and me mentioned before. I remember that very well from my aircon. It should be covered 3/4th or so - watch the video provided by 3M but do not cover it completely.

If you live here, air purifier I think is easier to replace the filter and lasts longer. Filtrete is not so cheap actually because it need to be replaced so often. Filtrete is great if you come to travel and there is unexpected smog like last week. So you have no more luggage as you had if you bought something as a purifier.

On 1/1/2020 at 11:26 AM, TallGuyJohninBKK said:

 A HEPA air purifier is going to do a better job of cleaning your indoor air, especially the smallest particles that are the most harmful, compared to the Filtrete sheets. The Filtrete sheets are better than nothing. But less capable than a HEPA filter.

 

I run my room air purifiers as needed to keep my PM2.5 readings in the room below 12 micrograms. If the ambient air is REALLY bad and my air purifiers couldn't keep up, then I'd add Filtrete sheets to my air con in addition.

 

 

Bad idea to put PM 2.5 filters on the air conditioners because the air conditioners also help to clean the air, put the filters in addition to quickly blocking and the air inlets prevents their proper functioning, the air conditioners also remove the micro particles with condensation on the air conditioner coils , the two machines can work well in parallel for a quick improvement of the air.