Is this O.k or not. What you are looking at is the box area at the return vent inside the home.
Where is the filter?
Consider what type of air is being pulled through that cavity and also the that the box will draw from seams in the drywall along with cold basement air maybe.
Seems like there are always some issues when I see that setup.
I took out the filter for the photo. Yes it was nasty. This is located in the hall way.
Is it possible this location can allow air into the return from the furnace area.?
I had the boxes under the furnace and recommended ducting be added immediately.
No. It is for the Heat Pump air handler.
Never see those here.
No problem, but seems like a flex duct could be thrown in for healthy air reasons.
Those filters only do so much.
Contrary to popular belief, the manufacturers state that the furnace filters are for the equipment not indoor air quality.
I agree. The placement of the filter confirms that.
The truth is that the panel filters were primarily for equipment protection because they were mostly effective on the lint fibers floating around in the air and they make up about a third of the weight of the stuff floating around in residential air. In fact, the ASHRAE test dust used to test them for arrestance was about a third cotton linters. The panel filters kept the lint from reaching the cooling coil and fan blades, clogging them up. Back then, homes were pretty leaky and well ventilated.
Then, homes got tighter and this thing called indoor air quality came along. Filters then became important for removing the other stuff from the air that affected people. BTW, note the debris on the frame where air has been by-passing the filter for quite awhile. It illustrates a problem that most people overlook in that our ratings are for the filter media and NOT the filter system. Air bypass makes the system less efficient at trapping stuff than the filter itself.
I have seen this many times when I lived in Texas. Not the best IMHO, but it gets the job done, even though poorly. I have actually cleaned a few of them out for people just to make myself feel better.
Is that why they make HEPA filters?
No, they make those to fool people, that don’t listen to the manufacturers of the equipment, into buying crap they don’t need.