[HN Gopher] Measuring My DIY Air Purifier
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       Measuring My DIY Air Purifier
        
       Author : crescit_eundo
       Score  : 28 points
       Date   : 2025-09-27 23:07 UTC (3 days ago)
        
 (HTM) web link (chillphysicsenjoyer.substack.com)
 (TXT) w3m dump (chillphysicsenjoyer.substack.com)
        
       | polishdude20 wrote:
       | I'd be interested to know the decay rate when neither the window
       | is opened or the air purifier is on.
        
       | Rebelgecko wrote:
       | Power consumption (maybe CADR per watt?) is also interesting to
       | measure. From what I've seen, that is the main dimension where
       | homemade purifiers can lag behind dedicated ones. Well, that and
       | aesthetics which is more subjective :)
        
         | jerlam wrote:
         | The CR-boxes are rather bad in that regard, but the newer
         | generation of PC-fan builds are significantly better than
         | mainstream HEPA purifiers:
         | 
         | https://housefresh.com/cleanairkits-luggable-xl-review/#the-...
        
           | BizarroLand wrote:
           | For comparison sake, a 20 inch box fan, which many CR filters
           | are made from, consume 60-85 watts depending on their speed,
           | which is 50-100% more electricity.
           | 
           | This could be improved by finding more efficient fans, but if
           | you're going for the cheap $25 fans at your local big-box
           | store, you'll pay more for it over time in electricity costs.
           | 
           | I have one as well, but I live in a geodesic dome home and
           | use it in the largest open portion of my house.
           | 
           | The ceiling at its highest point from the lowest point is 18
           | feet up, and the open section is about 1/2 of my entire home,
           | so the one 20" fan keeps air circulating and being filtered
           | for an enormous portion of my home.
           | 
           | If you live in a more typical home, the 20 inch box fan CR
           | filter might be overkill.
        
             | londons_explore wrote:
             | The $2 PC case fan wins on both price, power consumption
             | and quietness, and seems able to filter a roomful of air in
             | an hour or so.
        
               | BizarroLand wrote:
               | You will spend a bit more buying a few of them, a 12v
               | power adapter, and the shell to tie everything together,
               | but you are correct.
        
               | londons_explore wrote:
               | If you buy the cylindrical air filters, you can pop one
               | on a table, pop a case fan on top, and hook it up to a
               | phone charger via a 20 cent Usbc adaptor.
               | 
               | As a bonus, the USB-C PD adaptor has selectable voltage
               | (5, 9, 12v) on little dip switches, and that can be used
               | as a speed control for a 12v fan.
               | 
               | Turn it up to max when cooking, and down to silent again
               | when sleeping.
               | 
               | No need for any fixings or case or anything.
        
           | odie5533 wrote:
           | I have a Luggable and love it! So quiet and yet loads of
           | airflow!
        
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