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Old 17-04-2019, 08:26 PM   #2851
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Coz the dust is on the ground/furniture surfaces? Anyway dust is so much bigger also. Totally different things.
Nighttime pm 2.5 becomes 20+-30+ .

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Old 20-04-2019, 09:49 AM   #2852
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Question

Over the past few weeks I have been researching air purifiers, my conclusion is that I plan to buy the Coway AP-1512HH Mighty from Amazon US (currently USD $162)

I understand the voltage and frequency difference between US and Singapore (US is 120V 60Hz, Singapore is 230V 50Hz.) Therefore, I will buy a transformer to step the voltage down (I plan to buy the LiteFuze LC-300UK 300Watt Step Up/Down Travel Voltage Converter from Amazon US, since this Air Purifier is rated at 77W, I guess that a 300W transformer should be more than enough)

However, after doing more research, I also found there could potentially be problems arising from the difference in Frequency (50Hz vs 60Hz) Some websites I looked at claim that frequency difference can cause motors/fans to spin at a different speed, which could potentially cause overheating and damage.

I understand that no one can 100% guarantee whether this setup will work, but is it likely to be “OK”, or is there a significant risk of the air purifier breaking?
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Old 24-04-2019, 03:03 PM   #2853
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Over the past few weeks I have been researching air purifiers, my conclusion is that I plan to buy the Coway AP-1512HH Mighty from Amazon US (currently USD $162)

I understand the voltage and frequency difference between US and Singapore (US is 120V 60Hz, Singapore is 230V 50Hz.) Therefore, I will buy a transformer to step the voltage down (I plan to buy the LiteFuze LC-300UK 300Watt Step Up/Down Travel Voltage Converter from Amazon US, since this Air Purifier is rated at 77W, I guess that a 300W transformer should be more than enough)

However, after doing more research, I also found there could potentially be problems arising from the difference in Frequency (50Hz vs 60Hz) Some websites I looked at claim that frequency difference can cause motors/fans to spin at a different speed, which could potentially cause overheating and damage.

I understand that no one can 100% guarantee whether this setup will work, but is it likely to be “OK”, or is there a significant risk of the air purifier breaking?
People have done it before in 2013 haze, Honeywell stuff.

It's more trouble than it's worth.

Shipping is usd 106 btw.
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Old 24-04-2019, 08:26 PM   #2854
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People have done it before in 2013 haze, Honeywell stuff.

It's more trouble than it's worth.

Shipping is usd 106 btw.
Thank you for your reply, and for the info. Actually, I am based in Hong Kong (voltage and frequency here in HK is exactly the same as Singapore.) I use a package forwarding service which charges HKD $24 (approx. USD $3) per pound of weight, since the weight of this air purifier is 18 pounds, the shipping fee will be approx. USD $55.

The cost of the Coway Mighty is currently USD $162, plus another USD $32 for the transformer. So the total cost of Air Purifier + transformer + shipping will be approx. USD $249.

If I decided to buy an air purifier locally here in HK, from my research it seems the best choice would probably be the Philips AC3259/31, which sells for HKD $3,900 (approx. USD $503.) Therefore, I would save approx. USD $250 by choosing the Coway Mighty.

Furthermore, from my research it seems the Coway Mighty is a better purifier, and my main goal is to get a high-quality purifier at the lowest possible price.

When you say “it’s more trouble than it’s worth”, do you mean there is a risk of malfunctioning/breaking due to the 50Hz / 60Hz frequency difference? Or are there also other potential problems I am not yet aware of?

Thanks again for your help with this!
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Old 24-04-2019, 09:30 PM   #2855
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Thank you for your reply, and for the info. Actually, I am based in Hong Kong (voltage and frequency here in HK is exactly the same as Singapore.) I use a package forwarding service which charges HKD $24 (approx. USD $3) per pound of weight, since the weight of this air purifier is 18 pounds, the shipping fee will be approx. USD $55.

The cost of the Coway Mighty is currently USD $162, plus another USD $32 for the transformer. So the total cost of Air Purifier + transformer + shipping will be approx. USD $249.

If I decided to buy an air purifier locally here in HK, from my research it seems the best choice would probably be the Philips AC3259/31, which sells for HKD $3,900 (approx. USD $503.) Therefore, I would save approx. USD $250 by choosing the Coway Mighty.

Furthermore, from my research it seems the Coway Mighty is a better purifier, and my main goal is to get a high-quality purifier at the lowest possible price.

When you say “it’s more trouble than it’s worth”, do you mean there is a risk of malfunctioning/breaking due to the 50Hz / 60Hz frequency difference? Or are there also other potential problems I am not yet aware of?

Thanks again for your help with this!
There were reports of devices popping due to the transformer malfunctioning. Not only APs but other devices as well, like water flossers. That HWZ 2013 Amazon thread is gone now. Coz Air purifiers can usually last fairly long, however once you introduce a voltage convertor which is basically a transformer type of device, you introduce another layer of unknown.

Anyway since you are in HK, just get a Xiaomi 2S or Xiaomi Pro. I reckon that the floor area is very precious, so perhaps a Xiaomi Pro is better.
One for each room. It's noisy in the higher fan speed settings, but then if you are not using this to counter allergies (thus needing at least 5 ACH/Air Changes per Hour) but rather to counter HK/Kowloon's AQI 100-149 air which probably happens somewhat regularly, then it should be more than sufficient.

I think a few years back it hit > AQI 200 for a day or 2 (purple on aqicn) due to some unseasonal winds coming from the north hence bringing somewhat smoggier air from the Greater Pearl River Delta down, but that's about it.

The Xiaomi 2S or Pro shd handle that kind of conditions no worries. Tried and tested in SG and CN and northern Thailand smog and haze (very popular there in N Thailand via Lazada thailand, coz there are very few other choices anyway even if price is not a factor). Actually if you are a HK citizen, you should have watched all the China Air Purifier reviews/tests on youtube or youku or what.

And besides, replacements are real easy and cheap. Just get it from TB, or i am sure HK retail has it, or from some HK online platform.

The Xiaomis would work as well as the Philips or Coway generally speaking, don't worry about it.
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Old 25-04-2019, 04:45 PM   #2856
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There were reports of devices popping due to the transformer malfunctioning. Not only APs but other devices as well, like water flossers. That HWZ 2013 Amazon thread is gone now. Coz Air purifiers can usually last fairly long, however once you introduce a voltage convertor which is basically a transformer type of device, you introduce another layer of unknown.

Anyway since you are in HK, just get a Xiaomi 2S or Xiaomi Pro. I reckon that the floor area is very precious, so perhaps a Xiaomi Pro is better.
One for each room. It's noisy in the higher fan speed settings, but then if you are not using this to counter allergies (thus needing at least 5 ACH/Air Changes per Hour) but rather to counter HK/Kowloon's AQI 100-149 air which probably happens somewhat regularly, then it should be more than sufficient.

I think a few years back it hit > AQI 200 for a day or 2 (purple on aqicn) due to some unseasonal winds coming from the north hence bringing somewhat smoggier air from the Greater Pearl River Delta down, but that's about it.

The Xiaomi 2S or Pro shd handle that kind of conditions no worries. Tried and tested in SG and CN and northern Thailand smog and haze (very popular there in N Thailand via Lazada thailand, coz there are very few other choices anyway even if price is not a factor). Actually if you are a HK citizen, you should have watched all the China Air Purifier reviews/tests on youtube or youku or what.

And besides, replacements are real easy and cheap. Just get it from TB, or i am sure HK retail has it, or from some HK online platform.

The Xiaomis would work as well as the Philips or Coway generally speaking, don't worry about it.
Thank you very much for your detailed reply, this information is very useful. It makes sense there is a risk of the transformer malfunctioning, I think I will now probably abandon the idea of buying a 120V AP.

I am an expat living in Hong Kong, unfortunately my Chinese language ability is not that great so it can be difficult to understand Chinese reviews.

You are correct that Xiaomi 2S is available in HK retail, it is widely available locally for HKD $1,099 (approx. USD $140) which is obviously very cheap. Today I went to an electronics store to look at the Xiaomi 2S, I am happy with the price but have some concerns about the quality. Specifically, I am concerned about the quality of the HEPA filters, are they on a par with leading international brands such as Coway / Philips?

One other final option I am considering is buying the Blueair Blue Pure 221 from Germany. Since Germany uses the same Voltage/Frequency as HK/SG, there is no need to use a transformer. I have found an online retailer in Germany which sells this AP for EUR 316. They can deliver directly to HK for just EUR 35, so the total cost + delivery would be EUR 351, which is approx. USD $390.

From my research it seems the Blueair Blue Pure 221 is basically the 230V version of the Blueair Blue Pure 211, which is the highest ranked air purifier amongst all 36 reviewed and tested by US website Consumer Reports. Has anyone here ever used this AP?

Any thoughts on whether I should go for the Xiaomi or the Blueair?
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Old 25-04-2019, 07:33 PM   #2857
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Thank you very much for your detailed reply, this information is very useful. It makes sense there is a risk of the transformer malfunctioning, I think I will now probably abandon the idea of buying a 120V AP.

I am an expat living in Hong Kong, unfortunately my Chinese language ability is not that great so it can be difficult to understand Chinese reviews.

You are correct that Xiaomi 2S is available in HK retail, it is widely available locally for HKD $1,099 (approx. USD $140) which is obviously very cheap. Today I went to an electronics store to look at the Xiaomi 2S, I am happy with the price but have some concerns about the quality. Specifically, I am concerned about the quality of the HEPA filters, are they on a par with leading international brands such as Coway / Philips?

One other final option I am considering is buying the Blueair Blue Pure 221 from Germany. Since Germany uses the same Voltage/Frequency as HK/SG, there is no need to use a transformer. I have found an online retailer in Germany which sells this AP for EUR 316. They can deliver directly to HK for just EUR 35, so the total cost + delivery would be EUR 351, which is approx. USD $390.

From my research it seems the Blueair Blue Pure 221 is basically the 230V version of the Blueair Blue Pure 211, which is the highest ranked air purifier amongst all 36 reviewed and tested by US website Consumer Reports. Has anyone here ever used this AP?

Any thoughts on whether I should go for the Xiaomi or the Blueair?

Just go for the Xiaomi. All these filters can do 0.3 microns no issue.
The CADR (Clean Air Delivery Rate) of the Xiaomi 2S and Pro are 310 m3/hr and 500 m3/hr respectively. That is the spec to look out for, and after that would be things like noise level and then power consumption.

The 2S and Pro are pretty ok after you dial down the speed in the app control, just that in max fan speed mode they are very loud, louder than other APs in max fan speed mode. However the thing is that these APs are pretty small in size, so if you are talking about device volume : noise ration, the performance is still decent. And also due to the its taller stance and small foot print, it makes sense in a small apartment in Singapore or HK.

There is a small -ve of the Xiaomi 2S and Pro, actually any Xiaomi air purifier. Their Auto fan mode doesn't really work, coz they set the higher fan speed to kick in at too high a PM2.5 ug/m3 concentration level.
It's a quirk of the AP, can't be helped. Seriously, quite a few other APs also are of this nature, so isn't a big deal.
Most of us just use manual speed, really not a biggie in real life usage.

Forget about the Blueair. The filters are extremely expensive.
The Blueair 221 has a CADR of 590 m3/hr, so it'd be like a Xiaomi Pro competitor. The good thing about the 221 is that it is relatively less noisy than the Pro (56 dBA for the 221 vs 69dBA for the Xiaomi Pro, which is bloody loud).

The Blueair 221 is 33 x 33cm x 52cm. Xiaomi Pro is 26 x 26 x 73cm.


There is another point called the Formaldehyde CADR, that is another point to consider for other pax having this specific need due to other reasons (basically VOC pollution and protection, touched before in the past 5 pages due to a very specific case that happened in Singapore).
But pls if anyone is having some formaldehyde outgassing issue, the correct way to treat it is not to have big ass APs with really high formaldehyde CADR (eg the X352 X83C Plus) but you'd need to get the temperature of the room to relatively high levels to speed up the outgassing.
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Old 25-04-2019, 07:37 PM   #2858
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Get 2 Xiaomi Pros if you feel like it, it'd give you 1000m3/hr CADR capability if the situation really needs it, but when they are throttled back, the noise levels shd be slightly lower than the Blueair 221 pumping the same amt of airflow. Basically then you'd be covered for 2 rooms, or you can use 2 x APs in a single room eg master bedroom).

And still you'd save on the filter and cost of 2 APs still ought to be cheaper than USD 390.

Do more shopping, am sure you can get cheaper prices on HK online sites.
Get in touch with your HK colleagues, xiaomi is a very ubiquitous brand over there. Everybody knows where to get the best price. HKers are extremely price sensitive like us Singaporeans.

eg In Singapore, we get our Xiaomi 2S at only USD 100 thereabouts. No way HK is going to be that much more than SG.
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Old 25-04-2019, 07:40 PM   #2859
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Blueair 221 - 33 x 33 cm = 1089 cm2 footprint.

Xiaomi Pro - 26 x 26 = 676 cm2 footprint. 2cps = 1352 cm2 foot print (no worries, can site them 2pcs side by side). But of coz, visually the Xiaomi Pro would be 73 cm tall, even though you won't be able to make use of that vertical space in real life be it the Pro or the 221.
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Old 26-04-2019, 06:23 AM   #2860
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Today I went to an electronics store to look at the Xiaomi 2S, I am happy with the price but have some concerns about the quality. Specifically, I am concerned about the quality of the HEPA filters, are they on a par with leading international brands such as Coway / Philips?

BTW, the CADR values of the Xiaomi has been verified before by 3rd party labs.

eg This is for the original ver 1 xiaomi. Published spec = 406 m3/hr

Tested 396 m3/hr




Actually Xiaomi has another bigger version called the Xiaomi Max, it has a CADR value of 1000 m3/hr. It's 2X the price of the Pro, but i reckon it's a bit less flexible in usage than having 2 pcs of Xiaomi Pro.
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Old 26-04-2019, 09:43 PM   #2861
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BTW, the CADR values of the Xiaomi has been verified before by 3rd party labs.

eg This is for the original ver 1 xiaomi. Published spec = 406 m3/hr

Tested 396 m3/hr




Actually Xiaomi has another bigger version called the Xiaomi Max, it has a CADR value of 1000 m3/hr. It's 2X the price of the Pro, but i reckon it's a bit less flexible in usage than having 2 pcs of Xiaomi Pro.
Thank you again for your kind and informative reply, this has helped me a lot. Since this is my first time to ever buy an AP, I would probably start by just buying one Xiaomi 2S (my apartment here in HK is extremely small, total size of entire apartment is only approx. 25 m2.)

You are correct that you can get cheaper prices on HK online sites. There is a popular shopping comparison website price.com.hk The price of HKD $1,099 is for the “official” Hong Kong stock. Another option would be to buy a parallel import (水货), which sells for approx. HKD $800.

Today I have been doing some more research about the Xiaomi 2S, there are two points I am concerned about:

1) During the video 「FView 出品」空气净化器横评(测试篇)the guy states that for Xiaomi it is NOT possible to separate the outer layer primary filter (used for filtering out dust, hair and large particles.) from the inner HEPA filters. Therefore, the only way to remove dust from the outer filter is by scrubbing it off.

I am concerned about this because I believe it is better to be able to remove the outer layer primary filter and wash with water to remove all the dust? I saw on reviews of other APs (such as Coway and Bluair) that users remove the outer filters and wash them with water.

2) I saw a website [ smartairfilters.com/en/blog/xiaomi-auto-mode-leaves-air-unsafe-86-hours/ ] which claims that for Xiaomi AP it is only possible to use manual speed for 3 hours, and that after 3 hours the AP will automatically go back to Auto mode. However there are also some comments there is a “workaround” to fix this, so maybe this isn’t an issue?
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Old 27-04-2019, 09:12 AM   #2862
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All my 5 x Xiaomi Pros do not auto trigger back to auto mode. I have been switching on throughout the night. Running under manual mode. Overnight.

But I not blasting at highest speed. Maybe very high / highest speed will? I not sure. Didn’t try. Too noisy. My comfort zone (for Hall AP) is running the manual speed @ coverage 23-40m2 selection. Didn’t auto trigger back. No issue.

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Old 27-04-2019, 10:46 AM   #2863
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Before I switched from other brands to Xiaomi, I also have qualms about the filter. Especially when you compare those that have relatively much thicker HEPA filter than Xiaomi.

I have used several brands before I changed all to Xiaomi. Not that they no good. They are good. But original filters are getting expensive. I just need something that able to bring down the PM2.5 fast and yet, low maintenance cost. And I was looking at mobile app operating that time also. All purifiers have their own pros and additional functions. Some more features. Some lesser. If looking for something that emits negative ions, then Xiaomi AP is out of the picture.

I used a stand-alone PM2.5 device to check the air “quality” from the outlet. Xiaomi or non Xiaomi, clean air coming out - in terms of PM2.5 readings. Able to achieve what I’m looking for.

As for filters “lasting” (Xiaomi and non Xiaomi AP that I have used before), all have tint smell as time goes by. (At least for my usage/ environment/ situation/ at that time) Maybe some faster. Some slower. Depends on situation. Since Xiaomi filters are relatively cheaper, I just change them when the filter lifespan reaches around 30%. I usually don’t wait until 0% (individual preference). I no longer bother about vacuuming or clean or whether able to wash prefilter, this and that.

Choose a purifier that one feels most comfortable with it. There’s no “best” purifier imo. All got their own pros and cons. Depends on individual.

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Old 27-04-2019, 11:30 AM   #2864
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Thank you again for your kind and informative reply, this has helped me a lot. Since this is my first time to ever buy an AP, I would probably start by just buying one Xiaomi 2S (my apartment here in HK is extremely small, total size of entire apartment is only approx. 25 m2.)

You are correct that you can get cheaper prices on HK online sites. There is a popular shopping comparison website price.com.hk The price of HKD $1,099 is for the “official” Hong Kong stock. Another option would be to buy a parallel import (水货), which sells for approx. HKD $800.

Today I have been doing some more research about the Xiaomi 2S, there are two points I am concerned about:

1) During the video 「FView 出品」空气净化器横评(测试篇)the guy states that for Xiaomi it is NOT possible to separate the outer layer primary filter (used for filtering out dust, hair and large particles.) from the inner HEPA filters. Therefore, the only way to remove dust from the outer filter is by scrubbing it off.

I am concerned about this because I believe it is better to be able to remove the outer layer primary filter and wash with water to remove all the dust? I saw on reviews of other APs (such as Coway and Bluair) that users remove the outer filters and wash them with water.


2) I saw a website [ smartairfilters.com/en/blog/xiaomi-auto-mode-leaves-air-unsafe-86-hours/ ] which claims that for Xiaomi AP it is only possible to use manual speed for 3 hours, and that after 3 hours the AP will automatically go back to Auto mode. However there are also some comments there is a “workaround” to fix this, so maybe this isn’t an issue?
(1) The prefilter can be cleaned by vacuuming. I am sure you have cleaned your aircon prefilters with vacuum before. Very little difference vs washing, in the context of the air purifier.
I have a Mfresh M8088A that has a filter construction that is the same as the Xiaomi (ie cylindrical filter with prefilter built into the cylindrical filter, just that the Mfresh is a bigger filter. I also vacuum my Sharp and Samsung AP prefilters, though sometimes i do wash that.



(2) Yes, if that ever happens, just set timed programs. Seems like Lucky177 does not get it with his XM Pro.

https://forum.thaivisa.com/topic/108...mment-13816765

Second is the Manual Mode if set above ~50% fan speed will revert to Auto Mode after 3 hour - basically shutting itself off... My guess this is to reduce motor wear and filter usage...

But you can easily work around this problem by setting up a timer setting to reset the unit prevent the 3 hour mode change from Manual to Auto... Just add automation rules that turns the unit off & on every 2.5 hours and the purifier will stay in manual mode for the whole programmed time...

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Old 27-04-2019, 08:29 PM   #2865
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(1) The prefilter can be cleaned by vacuuming. I am sure you have cleaned your aircon prefilters with vacuum before. Very little difference vs washing, in the context of the air purifier.
I have a Mfresh M8088A that has a filter construction that is the same as the Xiaomi (ie cylindrical filter with prefilter built into the cylindrical filter, just that the Mfresh is a bigger filter. I also vacuum my Sharp and Samsung AP prefilters, though sometimes i do wash that.

Hey WussRedXLi and Lucky177, thank you both for your replies! That’s all my questions about AP now answered, my conclusion is that I will start by buying one Xiaomi, then add more later if necessary.

On a separate topic, I have also decided to buy an Air Quality Monitor (to keep track of the quality of air in the apartment BEFORE and AFTER using the new AP, so I can make a solid judgement on the AP's performance)

From the research I have done online it seems that the Laser Egg 2 Air Pollution Monitor might be a good choice? (It costs RMB ¥599.00, which is approx USD $90)

Would you recommend this one, or are there any alternative Air Quality Monitors you would recommend instead?

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