Converting 1″ filter frames to accept 4″ filters
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Converting 1″ filter frames to accept 4″ filters

October 13, 2019


If you’re like me you’re probably trying
to get the best air quality that you can inside your house. I too like many people love to put these pleated filters in here, but I just can’t
believe the resistance that these things have with these high MERV rated filters. This is a MERV 7 I believe and as you pull it out you can just imagine the airflow restriction that this has. What I’m going to do is I’m going to convert this a this whole unit right here from a 1 inch filter to a 4 inch
filter and I’m going to put two 4 inch filters in here and get a higher MERV rating up to even 11 but reduce the airflow restriction
greatly so to convert my my 1 inch filter frame to accept a 4 inch filter I had to do a couple things… First I had to get some tin snips and
cut this flange that was on the 1 inch filter frame. That what the actual filter would ride
against. Now that’s removed, I can have a 4 inch filter installed here. These little angle brackets here, I got
them at Lowes. There are actually for a T-bar ceiling. They go up against the ceiling and that’s what the actual drop cieling rides on and lays against. I just cut
these things to length mitrered corners and screwed them in place with a couple of drywall screws. A pretty simple job to do
the only thing that is a little bit challenging is because this wood frame is actually larger than the filter frame here I have a little bit additional clearance
so my filters don’t fit exactly. So i’m going to have put some foam strips to make my filters nice and centered within the frame. But, these were less than 4 bucks and it took me about half an hour to convert this 1 inch filter frame into a 4 inch filter frame, so I can get those nice fancy 4 inch filters in there and get
a lot better air flow through my A/C system. Once installed the airflow resistance is much less with
these 4 inch filters stalkers but these things also promise about one
year of life life, although I’m a keep a close eye and I’m gonna change these
things out when whatever they get dirty. I opted for these carbon impregnated filters. I don’t have
smokers in the house and I don’t have pets but what the heck the price was right, and the quality of these filters are pretty good. This particular filter
here is in a cardboard frame which most of them are. You can get some metal ones but I personally don’t see the point in spending that kinda money in the metal
frame with something you are going to replace anyway. It’s got a metal backer on here
to help keep the debris from going down into your A/C system. Like I said it’s all cardboard but it looks like it’s glued together pretty well
and it’s pretty, pretty durable the actual unit measures 15 1/2 by 24
1/2 by 3 3/4 and I got a tape measure and those dimensions were pretty accurate. Now these particular filters that I bought are MERV 8’s and I’m replacing the one-inch
MERV 7’s and I person couldn’t tell you if they
do a good job filterting the air. I don’t have any way to measure
that, I what I can tell you is that the quality things I think are very very
good I think the air resistance that these
things provide or the lack of air resistance that these things provide are I think very good as
well. Its actually why I went with these 4 inch filters Build quality is good, carbon impregnated
and to be honest for the price that I found
these things online, I thought is was a very good deal. So I will continue using these things in the future.

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  1. I know things have changed in the two years since you posted this video but just so people know, you don't necessarily have to do this conversion. They have media filters with lips on them. They fit right into your existing system (as long as they make the same size as your existing return vent). Here's a link to one.

    https://www.amazon.com/20x30x5-19-75×29-75×4-38-Aftermarket-Honeywell-Replacement/dp/B0012W6JS2/ref=sr_1_1?ie=UTF8&qid=1513335415&sr=8-1&keywords=media+filter+20+x+30+x+5

  2. Where did you find that the Accumulair carbon filters are MERV 8? I've looked in to them and can't find any specifications for the MERV rating for them. Any reference I've seen to the MERV rating from the manufacturer is that they are not MERV rated they are only for odor control if you want good filtering buy an electrostatic filter.

  3. The air restriction from a 1 inch pleated filter was causing my heater to overheat and shutdown every few minutes thanks to a safety sensor. I removed the filter and the heater operated normally. I'm going to convert to 4 or 5 inch filters using your technique. Thanks!

  4. youll get much better airflow if you cut off the cardboard grills on each side of your filters. I do it every time i change my my filters and the air flow from the blower is not strong enough to suck the media through without the grills.

  5. Recommend fixed bar grille covers as they increase airflow on returns vs the stamped grille (restrictive) face owner has. I seen on one return an 18 pct increase and another 28 pct per data sheet.

  6. Every furnace using a wall grill can easily do this and it enables you to use higher MERV filters without causing air flow problems
    ……
    Well done!

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