HOW TO: Window dust/ pollen/ smoke filter

[John E Davies]

See this related thread for some initial ideas and comments.

https://olivertraveltrailers.com/forums/topic/5711-add-a-dust-smoke-filter-to-a-window-anybody-done-it-ideas-welcome/

Step 1 Seal the gap.

First, you need to seal the 1/4” gap between the window frame and the blind frame. 1/4” doesn’t sound like a big deal, but considering that is a 10 foot perimeter, it is a significant air leak, about 6 square inches! I chose this seal, 10 feet is just enough for one big LE2 window. Sealing the gap stops any unfiltered air from escaping that way, and in winter it will reduce cold air leakage.

Frost King V27WA, White EPDM Rubber Self-Stick Weatherseal Tape, D-Section, 9/16" W, 5/16" T, 10 ft L,

You need a 1/4” hole punch to make holes to go around the window screws, I already had one, but this would work:

Punch the holes one by one for each section. Mark the location of each screw head by pushing hard on the seal, it will leave a clear imprint on the back side. Mark the SIDE of the seal with Sharpie (so you can still see where to put the punch). With a wooden backer board, punch a hole. Because of the adhesive, the punched-out part will try to clog up the punch, remove each one with a small tool.

Once all the holes for a section are punched, install that piece and trim the end to clear the next clip. It helps to not peel off all the backing paper until you are ready for to set the last few inches in place. The seal should line up with the OUTSIDE of the window frame.

Finish installing all sections, it took just under 10 feet on mine. If you have a wallpaper roller you can roll the rubber down hard, otherwise finger pressure is fine. Since I had a little left, I added two small sections to the bottom of the BLIND frame to help support the paper filter frame. 

More to follow.

John Davies

Spokane WA

[John E Davies]

Step 2 Trimming the filter

I used a 25” long filter, because that is what goes in my home furnace. It fits OK but a 24” one would be better. These are high quality filters at a really good price.

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

Because you added a rubber seal in the corner, the filter hits it and won’t slide all the way to the end of the cavity. There was 3/4” gap on mine. 

Trim away the two offending corners, making sure that you don’t remove them entirely or the frame will be weak there. Use a razor knife and then CAREFULLY trim away the steel wires with some small cutters. If you are not careful they will make you bleed. Push any sticky-out bits inside so you won’t get poked.

This is how it should look from the outside:

And on the inside, the filter clears the seal in the two corners.

The screen slides easily.

John Davies

Spokane WA

[John E Davies]

Field testing and comments. Unfortunately the air is super clear, so I can’t actually see if the smoke smell gets trapped by the filter. View out the window: obviously it is restricted, but since I sleep head to front I can still see out toward the rear pretty well.

The fit: the filter actually seals pretty darned well, almost like it was intended for the Ollie window. Keep in mind my filter is an inch too long, a 24” one would seal better in the middle where the slider goes by.

Test setup, one MERV 12 filter in the rear curb side window.

Turned OFF solar and the fridge (it cycled and messed up the readings). No other known ( fluctuating) electrical loads.

Closed all other windows, bath vent and cabin door.

Opened the Maxx Air vent fully.

Using my Victron Connect app, I could watch the current draw from the fan. A higher amp draw means the fan is working harder. Other than the sound changes, that is the only way I could think of to quantify the effects. Note: the amp reading includes other operating devices, the fan uses less by itself.

Fan at 100%,

Window open, no filter 4.3 amps.

Window closed, no filter 4.4 amps.

Window open, filter installed 4.3 amps

Fan at 50%

Window open, no filter 2.0 amps

Window closed, no filter 2.05 ? amps

Window open, filter installed 2.0 amps

The fan obviously struggled a LOT at 100% with everything closed, which you would expect. At half speed it is not so obvious. Try it sometime with your trailer…..

The difference between with and without the filter is negligible, meaning the fan should not be stressed by the restriction. I could feel air coming in through the filter element, and nothing around the perimeter. Other than testing it in a wildfire smoke plume, I don’t know any other way to see if it works. I plan to seal two more windows and carry a total of three filters during my warm weather trips, that should really help, along with running my Honeywell HEPA filter.

I am pleased, and I will update this thread later in the summer. 

John Davies

Spokane WA

 

 

 

[dewdev]

Nice qilts and pillow covers on the beds. Did you purchase them or have them made?

If purchased from where?

[LongStride]

@John E Davies that looks real good.  When you came up with the concept in another post I knew that you would come up with something effective that did not look cheesy (ie duct tape).

[John E Davies]

49 minutes ago, dewdev said:

Nice qilts and pillow covers on the beds. Did you purchase them or have them made?

If purchased from where?

My wife found those five years ago, somewhere on Amazon. They are true Twins, I narrowed them a lot so they would work better on the Ollie “Twins” aka bunk mattresses.

John Davies

Spokane WA. 

[John E Davies]

Update, I bought some 16x24x1” filters to try, instead of the too-long 25” ones, they fit much better though you still cannot get the window latch closed, however the glass closes all the way now, so there should be no water leaks.

So I went ahead and completed sealing the other two windows, and trimmed two more filters, now I have a great way to pull in clean air when the smoke is bad. When not in use, they are covered by a 13 gallon white drawstring trash bag, inside the closet next to the outer wall.

John Davies

Spokane WA

[John E Davies]

Update with some help for those in the East that are facing hazardous smoke concentrations for the first time.

 

As Toxic Wildfire Smoke Lingers, Americans Are Turning to DIY Air Purifiers

https://www.grainger.com/know-how/equipment-information/kh-what-is-merv-rating-air-filter-rating-chart

I use MERV 12 filters in my central HVAC system at home (and also in the Ollie). I run the home fan  continuously when air quality is bad and in allergy season and replace the filter bimonthly.

Nordic Pure online filters home page at Amazon

John Davies

Spokane WA

[SeaDawg]

4 hours ago, John E Davies said:

Update with some help for those in the East that are facing hazardous smoke concentrations for the first time.

 

As Toxic Wildfire Smoke Lingers, Americans Are Turning to DIY Air Purifiers

https://www.grainger.com/know-how/equipment-information/kh-what-is-merv-rating-air-filter-rating-chart

I use MERV 12 filters in my central HVAC system at home (and also in the Ollie). I run the home fan  continuously when air quality is bad and in allergy season and replace the filter bimonthly.

That's a clever idea, @John E Davies. Since I already own a 14" 12v Endless Breeze FanTastic box fan, if I needed to, I could build something similar for the Ollie for under $100 with 14 x 14 filters, and run it on 12v, on the little dinette table.

I'm going to send this on to my BIL in New York. I suspect air Purifiers are as difficult to find there as are plywood and gensets during a hurricane warning here in Florida. 

I found even simpler box fan purifiers. One filter.  It still works, according to testing they showed .

https://pscleanair.gov/525/DIY-Air-Filter

https://smartairfilters.com/en/blog/how-to-make-diy-air-purifier/

[ShallowGal]

Works great for reducing drywall dust too!