There’s actually plexi-glass–eighth inch thick–in the window frame, between us and the open window. It fits the entire window area and sits where the screen typically screen sits and has silver tape all around the edges. It’s just hard to see in the photo.
Honestly the first thing I’d do is run the same tests next to a fireplace or circular saw. I’m guessing you’ll see similar numbers. Then run them in the hall outside your spare bedroom, I’m betting they’ll be barely noticeable.
If you can smell/taste it I’d worry, but unless you’re running it full time we constantly do things that put bad air into our houses, but we also let clean air happen so it’s a balance.
If you are running it constantly then it may be time to add in the cost of constant filtering, but as draftboard is the dirtiest thing you can cut that’s gonna be pricey.
I have an extended exhaust run and started out with the aluminum tape, but couldn’t kill the odor. Ended up sealing every joint and seam in the 4" metal vent pipe with a bead of caulk instead. every wrinkle in the tape is a potential source. I found I had to seal the booster housing as well like you did.
Took me almost a month after getting the machine to finally nail it. Zero smell now when operating.
I agree with you, @deirdrebeth, in the sense that we’re not using it nearly enough to worry too much. But it does smell some (and certainly the numbers are worse than they are even in our garage which can get pretty dusty), and it is aggravating, given how much I’ve done already to try to get things right. I’ll probably keep at it, maybe doing some caulking as per @PrintToLaser’s suggestion, including around the window frame itself, which may be part of the problem. Ultimately, I may have to replace the window to a simple double-hung, which will simplify things considerably. From what I’ve read it sounds like it takes most people some time to get it right, so I’ll just keep plugging away at it. I’m pretty sure I’ve solved harder problems eventually! Thanks for the support!