Honeywell HW-628
Pros
exhaust and fan work great in 100 degrees + in Chino, CA

Cons
Loud
reluctant to mount harware into new vinyl molded windows

great fan
nice fan - fits in lower sash of window - would be ever nicer if it would fit in top of window - I purchased four (4) fans, and had to make supports for them fit in top of windows for true exhauts effort - they work very well, I'm pleased with the fans

The best fans I ever bought for the hot summer nights
The original fan I bought says that I bought it in 1998, which atonished me considering how hard I worked it before one of the fans motors decided to not worked any longer during the end of the summer of 2006, I ran it for 24 hours a day for 3-4 months every year. I live on the second floor and during the summer this apartment can get up to 100 degees inside, it was impossible to get a decent nights sleep. Then I came across "[[ASIN: 105-1061563-7871465 Honeywell HW-628 twin window fan. "]]" That night I put it in the window on exhaust and for the first time I had to use a light blanket to sleep, that's how much it helped to bring in the cool air in from the small window across the room with the help of a fan. It's quiet, it does the job and I love it and I recommend it to everyone who has the same problem. Now I put a large fan in my kitchen to carry out the hot air and I am able to deal living in this apartment through the hot summer nights and days much easier and with more comfort. It was worth every dollar I spent on it. I bought another brand for the living room and it didn't have as much power even though the price was the same, it wasn't worth it.

Not as good as the fan I purchased a year ago
I purchased this fan because I already own one and it's great. The fastening devise for the accordian sides has been changed. It's easier to operate the current fasteners, but they don't hold the accordian sides open when the fan is in a vertical window opening. I will have to think of a way to rig the sides so they stay extended (not necessary with my older Honeywell fan). The fan does work great for exhausting air out of my apartment and for cooling (the room with the fan is usually between 8 and 12 degrees cooler than the rest of the apartment).

Great Fan I'm Sure, if it WORKED.
On a 98 degree day in the city, I opened the box and installed the fan in my window. When I turned it on, it didn't work. After checking all the outlets, etc, I finally had to take it out and send it back.