Adding more filtration to "Window" AC - HVAC engineer questions?

[AmirJustin]

We are installing two 24k Frigidaire "Window" AC's in wall holes in our shop.

It seems all these "window" Ac's have very basic thin filters, with definite possible gaps on the perimeter.

There is a 1 to 1 1/2" https://showbox.bio/ gap between the front face of the filter and the backside of the factory intake grille... space to add media.

Our use will be woodshop... often will have fine wood dust in air when the AC's are running.

I am wanting to buy bulk roll "filter media" to place in that space, to place on top of factory filter.

Then as maintenance either wash or throw out, whatever makes more sense.

Am learning about "MERV", basically the higher the # the finer particles it catches but of course w more resistance to air flow.

Don't know what MERV is overall best to choose.

Any experts on this to suggest best way to keep dust from inside unit... reason being to extend years between removing from wall sleeve and hosing out.

 

[Showkey]

First thought: Any added filter will likely cause problems........the unit will not like the reduced air flow.

 

[tonyciambrone]

Window units because they're cheap up front?

Honestly they just sound like the wrong tool for the job.

 

[MarkG]

They pull in OUTside air through the filters, correct? I guess I don't see how extra filters are going to help anything when the dust you want to filter out is INside your shop.

They probably were designed by an engineer who knows a lot more about them than most of us, so I'd leave it alone.

 

[jjrbus]

One mans solution for added filters for his mini split. Might be able to apply it to a window unit?

 

[u3b3rg33k]

i've seen a few woodshops with big through wall units, they all get plugged coils eventually. one of them had enough and just put in more windows and a big exhaust fan.
seems like a non-mini split system with oversized deep filters would be the right tool here.

 

[LS6 Tommy]

They pull in OUTside air through the filters, correct? I guess I don't see how extra filters are going to help anything when the dust you want to filter out is INside your shop

There is no filter on the condenser (outside). Increasing filter efficiency or thickness will most likely cause the evaporator to ice up.

Someone here made a cabinet to increase filter efficiency without decreasing the airflow. They posted their project in this forum.

Tommy