Forced Air Filters in window A/C units...

[red_october]

So the other day, now that it hasn't been running 24/7 to keep my appartment cool, I took the front off my Fedders A chassis Air Con to clean the filter. The filter that was in it when I got it off Craigslist was a rather less than satisfactory piece of green foam stuff that didn't seem to collect much stuff. Since I want to keep this unit in good shape, I set out to the hardware store to purchase a new filter for it, hoping to find a hard filter as I understand these were meant to take a hard-frame filter. What I ended up with was a 12x24x1" Forced-X-Air system filter that I cut in half. The filter is a 3M high-spec anti-allergen filter (I have terrific allergies...). It seems to cut the airflow down a little bit... am I in danger of causing the unit to ice up? The hardware store also stocks a 12x12x1" blue "30 day" filter that seems more permiable than the piece of green crap... but it's at least damn cheap. I don't want to clog up the coils with stuff, or populate my appartment with fine dust, but I dont' want to ice up or blow out my wonderful, wonderful, Fedders...

 

[toggleswitch2]

The themostst sensor bulb is within an inch of the evaporator coil, usually. As such it will sense freze-ups and stop the compressor temporarily. If your thermostat setting is 3/4 of the way to "coldest" or less, I believe you will be OK!

 

[retrochad]

I use the AAF American Air Filter cut-to-size filter in my Carrier 12,000 BTU window unit...this is I think designed for central systems but is kind of a more rigid material than the usual fiberglass. The unit did not come with any filter and this type filter has worked fine with no problems. I just change it as needed.

 

[retro-man]

I have picked up filters at home depot. They are supposed to be used in forced hot air heating systems. They are black on the front and blue on the back. They have a very high rating for removing pollen and other elements. It came in a hard plastic frame. I took it out of the frame and cut to fit the units. I also bought an additional one (without frame) and cut that to fit the other units. These work excellent for me. You can wash them by hand in the sink with a little palmalove rinse shake them outside and reinstall. These keep the coils very clean. The clean about 99% out of the air. I have checked and no noticable air reducation. Never an ice over. You might want to try these.
Jon

 

[sudsmaster]

Jon,

Hate to tell you, but those plastic-framed foam filters from Home Depot are quite lousy at filtering fine particulates. At least this is according to various filter reviews I remember reading. I believe the best non-powered (passive) furnace filter you can get these days is one of the Filtrete models. The Ultra model seems to work very well. Filtrete has an even more upscale version, which has a dust removal factor of 1750 vs the 1250 of the Ultra, I just can recall the product name at present.

The foam filter will give good airflow because it has relatively large pores and lets most of the dust through. It's better than the standard fiberglass, though.

 

[launderess]

Our AC tech told us the same thing; foam filters are pretty useless for catching anything else but large particles and hair.

Use an electrostatic type filter media made for window ACs, purchased as a job lot. Keep two cut down to size, and during the cooling season change the dirty filter about once a month or less, and put in a clean one. This allows me to wash the dirty filter and not wait for it to dry before reusing.

Whatever one does, it is important not to use filter media that restricts air flow too much for window units. That will cause the motor to work harder to get required air flow inside the unit.