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Can someone explain what's the result of filter utilization / capacity. Is it efficiency? Does it start spilling out particles? I feel like a 100% used filter

Can someone explain what's the result of filter utilization / capacity. Is it efficiency? Does it start spilling out particles? I feel like a 100% used filter will still do a pretty good job, so unclear how much of the utilization % has commercial reasoning?

Waterluvian 4y ago
My intuition is that the more “full” it is, the less air will flow through it, meaning it just doesn’t do as much. Not to suggest that what the manufacture decides “100%” is is actually that.
- oh_sigh 4y ago
  That's exactly right for HEPA filters, not sure about other types of filters though.
  - thaeli 4y ago
    This applies for any media filter. VFD drive on the motor can keep airflow constant and increase energy usage instead, but for most fans the increase in static pressure means less air volume. Heavily loaded filters can also have more air bypassing the filter, which may or may not be significant depending on the application. For this kind of air filter bypass just subtracts from the airflow through the filter media.
KennyBlanken 4y ago
Efficiency in terms of airflow goes down, and static pressure difference goes up - but the filters trap more of the particles going through them. Changing filters on furnaces and AC units is really important, since lack of airflow hurts efficiency. Wirecutter (which is usually trash) confirmed this in testing; versions of units that had been running for months or longer (ie one they bought a year ago and used in someone's home, vs a new unit bought new with little run time) tended to perform better in terms of how many particles they completely removed. The unit starts using more electricity to do the same work, has to run at higher fan speeds, etc. So it's a tradeoff between that and the cost and waste generated by buying more filters.
- ehPReth 4y ago
  curious - why is Wirecutter trash? I’ve been sorta feeling iffy about them for no real reasons but they seem highly recommended
  - rhexs 4y ago
    They almost always conveniently only recommend products that allow for referral fees.
    - aardvarkr 4y ago
      The product manufacturers don’t pay referral fees, it’s the retailer. So your entire argument against them is you’re mad they make money by linking to Amazon or target?
      - wincy 4y ago
        I’d definitely prefer something like Consumer Reports who has the budget to expose scams like Molekule who claim to invent some magical new type of air purification.
      - deleted 4y ago
        [deleted]
      - inferiorhuman 4y ago
        > So your entire argument against them is you’re mad they make money by linking to Amazon or target? That's not my entire problem with them, but it's a problem. Because they're reliant on referral fees their motivation is purely to get you to buy random crap whether or not it's any good. So long as their reputation holds up that's good, but once they start promoting crap there's going to be a long tail of folks who think "oh it's on wirecutter, it must be good". Take a look at their reviews. It's not that they promote stuff that they might get a kickback on, Wirecutter only promotes stuff they can generate a referral link to.
    - eli 4y ago
5e92cb50239222b 4y ago
I live in an very polluted area (average PM2.5 level in winter around 300 µg/m³) and have been running the same filter non-stop in a cheapest Xiaomi purifier for 1.5 years. It's almost black, but works fine, as confirmed by DIY PM sensors. I think it puts more strain on the motor, but I don't see any difference in efficiency.
sschueller 4y ago
My assumption is that a "Full" filter has a reduced airflow which means the fan pulling air in has to work harder. If it is spected very tight then I could see it failing more quickly.

Waterluvian 4y ago

My intuition is that the more “full” it is, the less air will flow through it, meaning it just doesn’t do as much. Not to suggest that what the manufacture decides “100%” is is actually that.

oh_sigh 4y ago
That's exactly right for HEPA filters, not sure about other types of filters though.
- thaeli 4y ago
  This applies for any media filter. VFD drive on the motor can keep airflow constant and increase energy usage instead, but for most fans the increase in static pressure means less air volume. Heavily loaded filters can also have more air bypassing the filter, which may or may not be significant depending on the application. For this kind of air filter bypass just subtracts from the airflow through the filter media.

KennyBlanken 4y ago

Efficiency in terms of airflow goes down, and static pressure difference goes up - but the filters trap more of the particles going through them. Changing filters on furnaces and AC units is really important, since lack of airflow hurts efficiency. Wirecutter (which is usually trash) confirmed this in testing; versions of units that had been running for months or longer (ie one they bought a year ago and used in someone's home, vs a new unit bought new with little run time) tended to perform better in terms of how many particles they completely removed. The unit starts using more electricity to do the same work, has to run at higher fan speeds, etc. So it's a tradeoff between that and the cost and waste generated by buying more filters.

ehPReth 4y ago
curious - why is Wirecutter trash? I’ve been sorta feeling iffy about them for no real reasons but they seem highly recommended
- rhexs 4y ago
  They almost always conveniently only recommend products that allow for referral fees.
  - aardvarkr 4y ago
    The product manufacturers don’t pay referral fees, it’s the retailer. So your entire argument against them is you’re mad they make money by linking to Amazon or target?
    - wincy 4y ago
      I’d definitely prefer something like Consumer Reports who has the budget to expose scams like Molekule who claim to invent some magical new type of air purification.
    - deleted 4y ago
      [deleted]
    - inferiorhuman 4y ago
      > So your entire argument against them is you’re mad they make money by linking to Amazon or target? That's not my entire problem with them, but it's a problem. Because they're reliant on referral fees their motivation is purely to get you to buy random crap whether or not it's any good. So long as their reputation holds up that's good, but once they start promoting crap there's going to be a long tail of folks who think "oh it's on wirecutter, it must be good". Take a look at their reviews. It's not that they promote stuff that they might get a kickback on, Wirecutter only promotes stuff they can generate a referral link to.
  - eli 4y ago

5e92cb50239222b 4y ago

I live in an very polluted area (average PM2.5 level in winter around 300 µg/m³) and have been running the same filter non-stop in a cheapest Xiaomi purifier for 1.5 years. It's almost black, but works fine, as confirmed by DIY PM sensors. I think it puts more strain on the motor, but I don't see any difference in efficiency.

sschueller 4y ago

My assumption is that a "Full" filter has a reduced airflow which means the fan pulling air in has to work harder. If it is spected very tight then I could see it failing more quickly.