Is the built-in Air exhaust better than the $995 air filter? (read for clarification)

I bought the $995 air filter because I am doing this in an apt. In short, I noticed when I unchecked the “GF air filter attached”, the fan seems WAY more powerful than the air filter even at the highest setting. How am I coming to that conclusion?
When I use the built in, the ENTIRE hose gets filled with air and is fully extended. It feels firm. But when I use the attached air filter, even with fan at full setting, the hose is soft and not fully in use (not sure if that makes sense or I need to post a picture).

Anyone else experience with this or is there a definitive answer?

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The best solution is to vent outdoors. The filter is for those who must use the machine where this is not possible.

The built-in exhaust fan will put the vent hose under positive pressure. With it disabled, the external fan in the filter or otherwise will put it under negative pressure.


I can’t answer the airflow question definitively, but I will say that this part isn’t too surprising.

When you are pulling air through that hose it’s in negative pressure, so it should look like it’s “deflated”. When you’re pushing air out of the GF with the built in fan, the hose is “inflated” with positive pressure.


What you are seeing is simple physics. The internal fan blows into the hose, thereby inflating it, while the fan in the air filter sucks the air out of the hose, deflating it. This tells you nothing about the actual air flow, as the effect would be the same if there was no air flow at all. However, an inflated hose will test its seals as air will try to escape, while a leak in a suction hose will make air go into the hose. In the case of the GF, the former leads to a smelly room while the latter does not.


Interesting. Science! This must be it.
Does the negative vs positive pressure make a difference, you think? (A difference in pulling smoke, pulling smells, pulling debris)

Interesting as well. If I want to minimize smells, I should stick to the air filter’s “negative pressure”. Well, that is if there is a leak (which I dont think there is).

I do like that the built-in fan turns off automatically after a job. I wish the air filter fan did this

Actually you want the filter fan running at least as long after the cut as it did during the cut as it will increase the life of the fiter considerably. Think of the filter as a series of caves. If you run only as long as you are cutting the junk piles up at the entrance of the cave while continuing to run the filter the junk is pulled in and spread out in the length of the cave, it just takes time for this to happen.


Interesting. Good to know! Last night it definitely ran a few hours longer haha. Well in any case, a way to set a timer for the fan instead of a manual knob.

On that note, is it bad, or maybe even good, to have the built-in fan AND the air filter fan running at the same time? Would that cause any issues/air flow?

Only as an either - or as the filter fills up you have to turn the filter fan to a higher speed, bur an external fan over 200 CFM going out a window can reduce the times the internal fan has to run. If you had a second in line washable filter limiting what got to the main filter it might extend the life of the main filter considerably as it would catch all the big stuff that is a high percentage of the total, and in that case might need a fan assist.

It’s in the instruction manual.

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