Had something similar happen in a 1920s bungalow I flipped last year. Figured the thick plaster walls would murder my Wi-Fi signal, but nope...somehow...

I totally get what you mean about the dust—honestly, I just accepted defeat and added it to my weekend chores. A quick vacuum with a soft brush attach...

Haha, 20 years? You're definitely riding that HVAC lottery ticket. I've flipped houses where the unit was older than me and still humming along fine. ...