In this article I'll describe the method I use to install replacement windows - a method developed over 15 years and hundreds of windows. In general, replacement windows should lower a home's heating and cooling costs, improve comfort, and reduce street noise. But that wasn't the case when the windows on the house shown here were replaced 20 years ago. For starters, the double-hung replacement units were installed out of level, which put the sash out of alignment and allowed air leaks. The fiberglass batt insulation packed in around the frames was also leaky. Worst of all, when I removed the units, I found that the original sash weights had never been removed, leaving the pockets uninsulated. I knew I could get rid of the drafts the customer was complaining about - and leave her with much nicer windows as well.

I use Paradigm windows, which are made in Maine (paradigmwindows.com, 877/994-6369). They come with two sash locks instead of one; this provides a tighter seal between the sash. I use the company's optional two-piece sill adapter, which snaps into the window frame and requires no cutting - you just slide the bottom piece down to fill the gap...

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