current project: save energy and create a more cohesive look by replacing 11 windows in our old home with dbl hung, new construction windows. The problem: 6 windows have a rough opening of 2'9" x 4'5", and 5 measure 2'5" x 4'9". The question: is it easier (cheaper) to make the openings wider and shorter, or more narrow and taller?
thanks in advance for the input!

The expensive ways to go are UP and WIDER, because you will have to replace the header above the opening. Slightly narrower or shorter are no problem, too much narrower or shorter and you will have to retrim both inside and out. Going down is about halfway in between; you'll have to do some minor reframing, and retrimming.

In your case, why not simply replace the same sizes? The difference isn't that great. Why mess around with the openings for so few inches? I'd say I could find lots of better ways to spend your money than that.

There is a general rule that a house will always look best with windows that are most like the originals. In most cases, that's very true. The kind of uniformity you suggest isn't always a good thing, but I'd have to see the house in order to really make a sound judgment.

great feedback, thx! unfortunately only 2 are original. the current openings are an odd mess of a few different eras of replacments. its an old farmhouse colonial, perhaps we'll just try and get the front windows to match and leave the rest as they are, the difference is not so noticeable, as you say, especailly from the inside. thx again.

Your best bet is to go with the largest size and make them all the same size. Pella has a service that will sent a service man out to your home to measure and make you a window needed to fit the size of your opening and assist you in choosing your best window. Also remember that air comes in through and around wdindows. Making the necessity to add extra insulation in at time of installation.

If some of the windows are previous replacements, then the openings may have been modified (made smaller) when they were replaced, so you may be able to go back to the original rough openings with only minor modifications. You will only know this if you remove some wallboard adjacent to the windows and examine the framing.

In addition to Pella, Marvin will also manufacture windows to fit your exact rough openings, at an upcharge from the standard size price. Marvin also offers true divided-light windows, which would be appropriate in an older house, depending on how old it is. Glass size was once a status symbol...in colonial times, glass could only be manufactured in small panes; that's why very old windows had divided lights. When glass became available in larger sizes, the larger panes were expensive, and thus, were used only in upscale houses. Then glass manufacturing developed so that huge panes were possible economically, and now true divided lights are a status symbol. Go figure.