How to weather-strip your windows

While it is true that modern windows are more energy efficient than their predecessors, it usually takes about 20 years to recoup the cost of the windows through savings in heating and cooling.

Instead of investing money to replace windows that work perfectly, invest a little time and money to make sure your existing windows are in working order. Add new weatherstripping and replace any that is old and worn.

You can quickly make those charming but rattling old windows airtight again. You'll need two types of weatherstripping — self-adhesive foam strip and vinyl V-strip. Both are very easy to apply.

1. Apply a self-adhesive foam strip to the bottom of the lower sash.

• First make sure the bottom of the sash is clean, so the adhesive will stick.
• Then cut the foam to the length you need with scissors, remove the protective paper from over the adhesive, and stick the foam strip to the bottom of the sash.
• If the upper sash is operable, apply foam to its top edge as well.

2. Apply a strip of vinyl V-strip to the channels on either side of the sash.

• Again, make sure the channels are clean, and cut two pieces of the weatherstripping to the length of the channel. Most V-strip is self-adhering.
• Even if it is, when using V-strip on window channels, it's a good idea to anchor it with a few brads.
• Use a nail set to make sure the brads are flush, so the sash won't catch on it. I
• f the upper sash is operable, you can weather-strip its channels, too.

3. If you notice a draft coming from the parting rails — the rails on the upper and lower sashes that overlap — you can put a piece of V-strip along the inside top edge of the lower sash.

• If the upper sash doesn't move, use self-adhering V-strip — you'll never get a hammer in to drive nails. Make sure the crease in the V-strip is facing down.