30x60 (cut-to-fit) Filtrete Hammock Filter by 3M

This lightweight fabric is NOT intended to be duct taped, so complaints that it is not strong for that use is naive and is like saying a Mercedes SUV is a failure because it can't plow your driveway.It filters the air passing through it and is great to place in the air intake on your window slim profile AC unit. After a month or two of use, it is obvious how much crud it has pulled from your air and stopped from entering your lungs.The photo attached shows the effectiveness of this simple fabric filter after a few days of air filtration in a window AC near a collection of candles that were burning in the room. All that carbon smoke would have otherwise been floating in the air your breath in the room.3M you have a winner here and anyone who complains that it falls for situations it is not designed for is just being silly at best.

I purchased the Filtrete Hammock to use as a pre-filter for a Sharp Plasmacluster air filter unit and a Alen A350. Because proprietary filters are very expensive for these units, I bought Filtrete Healthy Living Elite Allergen Reduction Filter, MPR 2200, (16 x 25 x 1-Inch), cut them in half and doubled them up to build my own filter for these units. To improve their function, I added a single layer of the 3M Filtret in front of the thicker MPR 2200 filter. This functioned well and was a low cost way to get near-HEPA quality filtration.

When I originally bought this stuff, I expected that it would be thicker and could serve as a "cut-to-fit" replacement for RV rooftop unit filters. I was a little disappointed when it arrived, since in fact is it very thin and flimsy.However, it all worked out. I have a standard foam RV filter in my units that I can easily blow out with compressed air from time to time, and it captures most of the dust and dirt. Then I cut a layer of this and add it to the "filter stack" to serve as a hepa filter. The combination means that the finer filter lasts much longer, and the amount of dust that stays in the camper (and in the AC unit) is much lower.If you do it this way, the media is easily cut with scissors and one sheet of this filter will get you eight 14x14 sheets.

These sheets are great for window units and some split units like the Mitsubishi Mr. Split but not good for other split units due to air flow impedance that may cause the unit to freeze up. They act like air purifiers too and will make cleaning your permanent filter unnecessary. I wonder if you can wash them out and use them again which I am experimenting with right now because of their high price for a sheet of material that seems to be not much too it yet pulls out so much out of the air I venture to say a well used one is bio hazardous. Even cigarette smoke will not make it through this filter.

I put this over my window and put my window fan in front of it. There was little airflow that went through I was afraid my window fan would get damaged by it. When I mean little airflow, I mean 90% reduction! I stretched it out some to thin it out and the problem still persisted.I wish I could return it but I have already cut it to use it. I would not buy angin and I would stay away from this product. Air filters are supposed to allow air flow otherwise what is the point.

I bought this last summer to control dust coming from my air registers, and now that cooler weather is here, I turned on my central gas heater. After warming up, the heater started turning on and off in unusual short intervals. I searched the Internet and this is called "short cycling". So it turns out the filter media is so good that it restricts airflow in the ducts. This back pressure causes overheating in the heat exchanger of the furnace which has a safety sensor to prevent overheating and turns it off. So I removed all the filters from my register vents and my central heat is working normally again.

I like the cut to size hammock filter because I have an air vented heating system in the home I rent, and I can just cut the filter and tape it over the air vents. The photo I added shows the white filter material on the left, and the filter after 2 months of use on the right. I put a piece of white paper below it so you can see the color better. The filter has cut back on indoor allergies for my family and it's a great alternative if you can't get your HVAC system cleaned if you're renting. The heated air still comes through the filter just fine, and painters tape works great to tape it over any vents.

We put this on our server fan/cooler. With the extreme amount of cooled air being pulled through the sponge filters - we needed something to pick up the finer particles. And, it cuts down on how many times we have to wash the main filters. With the amount of air passing through the system and, the building built in 1922 - we need to change the pre-filter every 30 days. A bargain - knowing that the air comes out cleaner.