[RWebb]

good advice - esp. if you ever resell it

it will also depend on where the window is located -- a south facing window will collect a lot OF THERMAL LOAD from radiation coming in. Awnings, roof extensions, or TREES will help tremendously with that and are cheap. "stuff on the outside" is better than drapes for heat gain issues

there was an energy act last year to give you tax breaks - IRS has info on their site - don't forget state tax breaks either -- I dunno how long the breaks last but they ARE good in 2010.

also call you utility co. and ask for an energy mgmt. specialist - around here, they are free and thicker than cockroaches

so do N. facing windows last or not at all