I live in the DC area and whenever I hear people say "just crack a window" I think, that brings in all of the pollen I'm allergic to in all seasons except winter, plus humidity and 95 f degree heat if it's the summer... I' be been looking into getting an ERV for a while.

The humidity and temperature are rough. Some months I can't open the window at all. This month has been pretty good though, huh? At least for the temperature and humidity.

I feel you about the pollen. I use a Blueair filter, and that keeps PM 2.5 and PM 10 in check.