Can you "double filter" on a return? (Ugly return installed)

We had a 5" Trion media air cleaner installed in our new A/C system. We're using Merv11 filters. There is no pre filter installed, just the main 5" filter.

For the 24" return, the HVAC company installed a non operational open slat grill that allows you to easily see the insides of the large return duct. Kind of unsightly.

I asked if that should be a 1" filter there, with a grill that opens, which would act as a prefilter, and also stop you from seeing the insides of the return in the ceiling. Additionally, since I can't open this easily, I can't insulate the return opening in the winter (lost heat into the system).

The HVAC company said having another filter in line would restrict air flow too much, which is why they don't do that type of a grill when they install a media air cleaner on the air handler.

I can provide a picture if needed, but is it ok to replace this grill with another style that has a 1" filter in it, so I don't see inside the return? How would this be different than if we had installed the prefilter with the 5" system?

Thanks!

 

I thought the A/C air cleaner/filter should be installed in the air handler right before the blower.

 

Can you? yes Should you? no Is it possible to paint the inside of the duct white or some non objectionable color? Post the picture if you don't mind, maybe idea will surface.

 

I've had diff filters over the years in diff houses and the best cost effective method I use now is the std cheap $2 filter with another filter layed across the front of it....the old black mesh stuff used in alot of window units, still available at some places. You can vacuum them or wash them. They do a super job of filtering, and the std filter provides the rigidity. Do it.

 

In my opinion stick with the media filter. They are great. What we usually do is paint the inside of the return flat black then you can't really see a thing in there.

 

Sounds like painting will be in order then. I definitely want the media filter. The odd thing was that rather than cut out a joist that ran through the return opening, they notched the return around the joist, assuming so they didn't have to frame out the opening (much more work). So I hate seeing the joist too. But I would imagine that after painting the whole thing it won't be noticeable.

What do folks do about heat escaping into the return in the winter? I can close all the supplies, but the two returns can't be closed, or easily lowered to put some insulation in there. Is the heat loss minimal and not worth worrying about?