Cleaning vs. Changing Air Filters?

[Mark J]

Doing a belated spring cleaning and have gotten to the Jet air filtration system.  I find it difficult to judge the condition of the air filters just by eye.  In fact for the home HVAC I change the filter according to the calendar, but that gets reasonably consistent utilization over time. 

With the workshop air filters it seems to be considered a sin to change these out unless the airflow is actually visibly diminished.  

I'm looking at my AFS filters and the pre-filter looks pretty filled, while the fine filter looks meh.  But the airflow seems fine.

So when do you say a filter is in need of cleaning or replacement?  And do you blow it out or replace it?  How many times can you blow out a filter, anyway?

[Chestnut]

I'd give it a light blow out once and then address replacement cost. I can't remember how much those filters cost but I remember it not being too much.

[Tpt life]

Typical wisdom is that modern filters fail from loading more frequently than from anything else. This approach means you need to figure a flow rate at which you fail the filter. 

[Mark J]

17 minutes ago, Tpt life said:

Typical wisdom is that modern filters fail from loading more frequently than from anything else. This approach means you need to figure a flow rate at which you fail the filter. 

Not really sure how I would make that assessment.  All I can say is that a goodly bit of air comes out the blow side and a seemingly similar amount goes in the suck side.  

So is it safe to say that particulates will not "work their way through" a loaded filter, but rather the filter will just stop passing air?

26 minutes ago, Chestnut said:

I'd give it a light blow out once and then address replacement cost. I can't remember how much those filters cost but I remember it not being too much.

I bought a set of replacements when I ordered the AFS.  Price tags say about $75 for the two of them.  Seems like a lot, but I probably spend more than that on HVAC filters.  And I've been running these AFS filters for going on 4 years.  The pre-filter has been cleaned 2 or 3 times before today, but the fine filter doesn't lend itself to being blown off.

[Tpt life]

Flow would be measured in a cfm measure at the inflow gate. As the filter loads, it clogs to such a place that not enough air will move to clear fines. You can get air flow meters you can hold in the inflow at your tools. Not sure the calculations each might require. 

[wtnhighlander]

The argument against cleaning, at least for paper and non-woven cloth filters, is that you can damage the media, and allow those fines to get through little tears. 

Given that most of my dust is filtered by nose-hair, I can't comment with any significant authority...

[Chestnut]

The dirtier filters are the more fine material they remove. hang a string in front of the unit with the new filters. When the blower blows the string half as far away, clean the filters?

[Askland09]

I get a new filter every other year with a cleaning every six months.  Just a personal decision but with my chronic sinus issues it really helps (or at least in my head it works who actually knows).   

[BillyJack]

I've been blowing out mine  for years. Works great.

Hvac unit in comparison? I don't think so.