Add a dust/ smoke filter to a window? Anybody done it? ideas welcome.

[John E Davies]

I already have a floor HEPA filter which works great when all the windows are closed tight, but I would like to be able to block some of the wildfire smoke from entering with a window cracked for ventilation. Sometimes I would have the AC running but fresh air is always a good thing when the temperature is cooler.  Actual window opening size for the big window is 16 1/4” tall x 22 5/8” x 5/8” deep. A filter that would wedge into that opening (screen removed, slider partially open) would allow the blind to operate. This obviously won’t work, this is the 16x25x1 MERV 12  filter I use at home, but it shows the gap that would have to be filled.

However they do make a non-pleated flat version just 1/2” thick that perhaps could be trimmed to fit (round two corners). You would need to figure out a way to retain it in the slightly larger opening, maybe with 1/4” stick-on weather stripping... a little air leakage would be OK but not desireable.

These are quite expensive, I don’t want to order them only to find that they won’t work, though Amazon has free returns, but these do not ship for three to five weeks. Any comments? Source for the filter material in bulk? With a vent fan running I think there would be some airflow through it.

John Davies

Spokane WA

 

[SeaDawg]

I'm wondering out loud, but, could you get a spare window screen and replace or just tape over the screen with filter material? 

(I hear @Overland has a small collection of them...)😆

If it works, I'd love to know. We don't have many issues with wildfire smoke, but I do have to double up on allergy meds during spring/early summer pollen season in the mountains, or I wake up all congested.  This could be an idea... I'd need to cut a piece big enough for the fan screen, too, though.

3m filtrete material can be purchased in a single piece,  in various thicknesses. This one mentions filtering out smoke. 

https://www.amazon.com/30x60-cut-Filtrete-Hammock-Filter/dp/B003DWE3OQ/ref=mp_s_a_1_3?dchild=1&keywords=filtrete+cut+to+fit&qid=1624221692&sr=8-3

[Overland]

27 minutes ago, SeaDawg said:

(I hear @Overland has a small collection of them...)😆

 

Yes, but they have sentimental value.

[Overland]

What about placing a filter over the max fan and running it in reverse to push air out of a cracked window?

[LongStride]

JD, I think that if you got ahold of a spare window shade assembly you could modify it to hold a filter, and then just snap it on as required.  Might need to add some type of gasket material at the edges and use some sheet styrene and a hot air plastic welder to build a filter rack.  If you have access to a 3D printer and the talent to use it (I have not) you could create a custom assembly that the filter could slide into that snaps into the clips that hold the window blinds.

I have been following your mods and you look like you have the patience and creativity to come up with something far more suitable than duct tape.  I am anxious to see what you come up with.

I can almost hear the wheels turning in your head...😉

[John E Davies]

1 hour ago, Overland said:

What about placing a filter over the max fan and running it in reverse to push air out of a cracked window?

I had considered that but I would prefer to use that fan for exhausting heat that collects at ceiling height. I have never even run it in reverse, is it at all effective that way? 
 

John Davies

Spokane WA

[SeaDawg]

Either way, you'd need a filter over the maxxair, or in my case, the fantastic vent.

I've always run mine in exhaust mode. Never tried it in reverse, to push through. It draws a significant breeze through a window open at the foot of the bed, in exhaust mode, even on low. But mine runs on a "thermostatic " control, so I'd have to cover the screen with a filter, I'm sure, in smoke.

With or without it running, campfire smoke creeps in, 40 feet away.

[Overland]

I’ve only run mine in reverse to see what it does. Like you guys, I’d much rather have it pull a nice breeze through the windows. 

[John E Davies]

It sucks to get old, I feel like an idiot. I put the frame back up and tried inserting that 16x25x1” filter, and it went in fine. When you lower the top blind and raise the bottom blind just one inch it holds it firmly in place with hardly ANY gaps. The window and screen slide perfectly. Inside views:

Outside views:

 

The only issue is with this 25” long filter the window won’t fully close.

 

 

If somebody has a 16x24x1 filter that you use in your furnace PLEASE TEST THE FIT, see if the window will close and latch. See if there is a gap at the front, where the center divider is located. Try repositioning the blind frame further to the back (mine is centered) - moving it rearward might do the trick, since the blind frame is what retains the filter. If the glass will latch, you could leave the filter in place with the window closed while traveling, or if it starts to rain. You could even install three filters in all the long windows of an LE2 if the air was horrible.

Here are the 24” ones, I have used these Nordic Pure ones for a long time in my HVAC system, they are affordable and effective.

Nordic Pure 16x24x1 MERV 12 Pleated AC Furnace Air Filters 6 Pack $43

I will test my 25” filter on the next trip. There may be a little dust seepage around the outside of the blind frame, there is a 1/4” gap there, but it would be easy to seal with foam weatherstripping. Some owners have done this to reduce cold air infiltration….

John Davies

Spokane WA