Is a Homemade Air Purifier as Good as a Brand-Name Air Purifier?

You know those white medical masks that you see nurses and doctors wear in hospitals? Back when I lived in Canada, I never saw anyone wear one in public. But here in Asia, they are pretty common. In Hong Kong, it’s generally an indication of people who are sick – doctors usually instruct their patients to wear one until they get better. But in mainland China, these masks are commonly used to combat air pollution, China’s biggest environmental problem.

Though China’s bigger cities (like Beijing and Shanghai) typically have the worst pollution, smaller cities can also experience days where the pollution is pretty bad. I’ve become far more appreciate of days where I can look up to a blue sky, as we only get to see this a few times per month.

Photo courtesy of

Photo courtesy of

Though there is little that we can do to control the air quality outside our home, there are ways to improve the air quality inside our home. Perhaps the most common method is by obtaining some sort of air purifier.

Unfortunately, while there are plenty of competing brands out there (such as Blue Air or Philips), they don’t come at a cheap price. A low-end air purifier will cost you 2000 RMB (about $320 USD), and you can easily spend thousands of RMB more if you want a higher-end model.

I recently stumbled upon an interview with Beijing-resident Thomas Talhelm, who invented this do-it-yourself air purifier as a significantly cheaper alternative. For only 200 RMB (about $30 USD), you can buy an air filter than he claims to be as effective as the more expensive brand name purifiers.

What makes Talhelm’s product so compelling is the fact that he has published the results of his tests and even listed step-by-step instructions on how to make one yourself. In the interview, Talhelm rightfully challenges the assumptions we as consumers make when purchasing air filters.

Unless we buy a particle counter, we have no way of assessing whether air purifiers actually work. And when we can’t assess the value of a product even after we use it, we’re likely to rely on the price to judge the quality. “If it’s more expensive, it must be better.” We see this all the time with wine, which is another product that many of us feel like we lack the expertise to judge.

-Thomas Talhelm, in an interview with

He’s totally right. Though the place where my wife and I are currently living is fully equipped with two Philips air purifiers, I cannot conclusively say that the air in my house is any different than the air outside. If nothing else, running those filters offer us psychological comfort. But once my wife and I move to a new apartment, we will definitely think long and hard before dropping a couple thousand RMB on an air filter.

What do you think? I’m curious to know if there’s anyone else out there who has heard about these air filters and/or tried them out.


7 thoughts on “Is a Homemade Air Purifier as Good as a Brand-Name Air Purifier?

  1. When we were living in Xi’an, we looked into the homemade filters and were seriously considering getting a few. We left quite unexpectedly, so we never did get around to it. Some of our American friends had them though and said they were pretty good. They got dirty pretty fast, which showed how bad the air quality in their apartment was before they got the filters…. Good luck deciding which one to get!

    • Yeah, it seems like you need to replace the filters pretty often. But it might still be worth it, considering how much money you save from not buying a brand-name purifier. I’ll give you an update when and if we decide to go with a homemade one!

  2. I am South African, I am so deeply saddened at the amount of trouble people have to go through for fresh air. Purifiers are not big if there are any in my country so I wouldn’t know much.

    • Hi Devyn Stella! Thanks for stopping by and leaving a comment! What’s the air quality like in South Africa? I’ve never been there before, but I would assume it varies city by city?

      • the air quality is sitting on ‘okay’ at the moment, slightly hitting the ‘moderately not okay’ button because industrial emissions are at an increase. the most industrialised city, jhb said have the most ‘dirty’ air quality.

  3. I’ve never really heard of homemade air filters. We did quite a bit of research before we bought our Alen filters. I disagree that it is not possible to test air quality indoors. Right now in Hong Kong, there is a city-wide indoor air quality test being run by the government. I see the equipment set up in stations all the time. It is possible to rent the equipment to do a proper test of your indoor air quality and while it may fluctuate day-to-day it will generally be in a similar range due to the off-gassing of your furniture (the biggest indoor pollutant, along with human-made dust). After SARS hit HK in 2003, the hospitals all invested huge amounts of money in air filters made by the company called IQ. Alen air filters are very similar in design. We got in on a group deal and got a discount and we also bought store models which were further discounted. We ended up investing about $2,000 USD. One of the BEST investments we ever made–especially considering we have young children, one who has recently been diagnosed with asthma. Some days it will be so bad outside that the smokey air is seeping into our apartment. We go home, turn on the air filters full-blast and within a couple of minutes we can actually feel the improvement in air quality. We may not test our home air quality regularly, however, we can tell when we don’t cough or get sick and our child doesn’t have asthma attacks regularly that the filters work.

    • Hi M! Thanks for leaving your thoughts. It’s so great to hear that your filter has helped improve the air quality in your home. How long have you been living in Hong Kong?

      I feel that air quality affects people differently. My wife, for instance, can tell when the air is particularly bad and she tells me that it makes breathing more difficult for her. On the other hand, I can’t really tell the difference (unless I can actually see smog, which is an obvious sign of poor air quality).

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