After being roused at the seemingly normal 3AM sneeze attack, some part of my slumbering consciousness realized the HVAC was blowing a little extra, but that the furnace wasn't on (the air was moving, but not warm). Then my lesser-conscious parts reminded my more conscious parts that we have an air exchanger. This further reminded me that the air exchanger has a filter. Further, I was reminded that this filter needs to be cleaned every month or so. and that I haven't cleaned it for so long I can't remember when I did this last. Whoops.

Checking just now, sure enough, equal parts nylon mesh filter stuff and grubby stuff that got filtered. I rinsed the reusable filter mesh bit in the tub, getting rid of the filtered stuff. I'm now running the filters through the laundry now (washer only; I'll hang them and let them drip-dry for a bit).

Hopefully tonight will be free of the usual overnight sneeze-fest.