See if you can get any energy credits from your local utility... we got 30% back on the cost of our windows. If we had paid for the install, it would have been a credit on both materials AND labor.

We are doing vinyl double panes with high E glass. It does make a huge difference in certain rooms. The funny thing is, the more energy efficiency improvements we do, the more we realize that the house has so many leaks, poorly insulated areas and so on. DH says that no house can be airtight.

More and more, I am grateful that DH is a pretty handy dude. We do all our own remodeling, one project at a time. Our only costs are materials. Mostly, we are just too cheap to choke down contractor costs on things we have the skills to do. The time frame is different of course. We've done the windows three or four at a time, usually over a weekend, and then a season or year later we do some more. We only have the two that require renting scaffolding to do. Granted, it's not all done at once, but the thousands of dollars we aren't paying someone else we get to use for fun stuff.

While some home projects require a lot of skill, a whole lot don't, they just require some time. As for know how, there's a lot of info online.