Filter box for AC

[Illini Trekker]

Right now I'm again working out of the camper in central Illinois for the next 6 months. Knowing the hot weather will soon be here and AC use will be a must I wanted to help cool the camper better and built a filtered return air box. A single piece of 1x4 10' long is all the lumber needed and four metal 90 brackets. Out side measurements are 21.5"x17.5" that a 16x20" filter will slide in. I did need to tape off the quick cool but didn't feel I needed it with the steady use of the AC unit.


I used a thin peal and stick foam between the box and ceiling to help with gaps.

This is an end view and where I can change the filter. The other corners are glued and nailed together.

The brackets are slid under the AC support bars, it did make a snug fit with no screw needed on AC side. I did use wood screw into the filter box.

A look at the box painted white, I have a grill cover but for now the look suits me fine.

[ole dude]

Lookin Good.

[bsmeaton]

You did a nice job, but this might have saved you a lot of work -



Around $60 at Camping World. I can't do either because it obstructs the path of the ceiling fan paddles on that angle.

[Illini Trekker]

Looked at the Camper World version for $75.00, and a review stated it had a 1/16" thick filter and this filter is probably not much more efficient than the original foam filter and seals up about as well.

Also inspecting the AC unit I did a little taping and caulking to help seal the holes around the unit. Found where the first joint of duct meets the second and the two had come apart and had 1/2" to 3/4" gaps between them. Looked like the AC was losing a lot of that cool air to the attic.

[hazmic]

Ours is also above the fan blades on our model. How much dose it cut down on air flow? I have read posts about units freezing up because of not enough air movement. Just food for thought. OZZ what do you think as you are in that business?

[Illini Trekker]

Back home for the long holiday weekend, to answer your questions with the new filter size being almost triple the size of the foam I fore see no problems. I guess time will tell as the Ac unit to date has never froze up on me. If the Ac would freeze I will drop down on the filter merve number to gain more air flow. The filter box is only 3 1/2" from the ceiling not sure if this will give you the clearance needed to miss the fan blades?