Vinyl windows have become the norm when window replacement becomes necessary. Although there are varying advantages to both Vinyl and Aluminum choices, there may also be disadvantages to both choices as well. The most important decision is probably the decision to upgrade to dual pane windows as opposed to single. The longevity of a single pane aluminum windows is probably acceptable. The biggest problem is that when the integrity of the window starts to fail, then your heating costs will increase dramatically. The seals around the window will start to allow the cold in and the heat out. So your overall heating costs will just continue over time to rise without any relief other than window replacement.

If you are on a fixed budget then one of the advantages to aluminum is that you can simply replace the windows that are bad, and replace the others later. This way they all match throughout the home, and won't change the aesthetics dramatically.

If money's not the issue than Vinyl windows are clearly the choice. In making this decision you must also consider the longevity of the vinyl windows, the added value to the house, and the later heating costs you will save from these windows as well.