As the weather cools, wind may be bent on finding a way into your house, but you're equally determined to stop them and stay toasty warm. Here's how you can keep cold drafts from getting in via a poorly insulated window. Spring-metal or V-shaped vinyl weather-stripping works very well and is almost invisible.
Review the installation diagrams to determine the exact location and orientation for the product you're using.
Clean all surfaces well, especially if you'll be using adhesive-backed weather-stripping.
To seal the channels, cut lengths of V-shaped or other spring-type weather-stripping about 1 inch (2.5 cm) longer than the height of each sash. Use tin snips or a hacksaw, or (for vinyl only) a utility knife.
Open the sash fully and slip one end of the strip behind it (see A). Then continue back down to the sill for the lower sash channel, or up to the head jamb for the upper sash channel.
To secure the strip, either peel off the tape and press the self-adhering type into place, or hammer in the small nails provided for metal types.
To seal the window at the horizontal rails where the two sashes meet when closed, cut a length of weather-stripping equal to the sash's width.
Partially open both sashes so you can access the front edge of the horizontal meeting rail on the upper sash. Install the weather-stripping on that rail with the point of the V facing up (see B) or the nailing flange at the top.
Cut and install additional strips equal to the sash's width to seal any gap between the top of the upper sash and the head jamb as well as between the bottom of the lower sash and the sill. Secure the strips to the top of the upper sash and to the bottom of the lower sash.
Measure the window's perimeter and cut four pieces of spring-metal or V-shaped vinyl weather-stripping to fit.
Position each piece as shown in the manufacturer's installation diagrams (with either the nailing flange or the point of the V facing outward).
Either nail or peel and press to apply the weather-stripping.
If you won't be opening the window often or at all in wintertime, consider installing virtually invisible storm windows (made of plastic film) that cover the entire window. These seal out drafts and add an insulating layer. You install reusable types in permanent moldings and tape in the temporary types.
Clean the surface well.
Cut adhesive-backed tape to fit the perimeter of the area you will cover, and then press it into place.
Remove the protective paper from the top strip.
Cut the plastic film with a razor or scissors so it will extend beyond the tape about 2 inches (5 cm) on all sides.
Pull the film taut across the top, just enough to straighten, not stretch, it. Then press it onto the tape.
Repeat the procedure at the bottom and then at the sides. Do one strip at a time to prevent the plastic from coming into contact with the adhesive until you are ready.
Use a hair dryer on a low setting to warm the film. This shrinks it and pulls out any wrinkles.
Carefully trim the excess with a single-edge razor blade or sharp utility knife.
Nailable metal is more durable than vinyl, which comes in both peel-and-stick and nailable forms. Gaskets seal well and install easily, but they're often unsightly and don't last. You never want to paint over weather-stripping, so now's the time to touch up or paint the surfaces where you're installing strips. A sliding window is like a double-hung unit turned on its side, so you weather-strip it in a similar fashion. Miter the corners of spring-metal and V-shaped vinyl weather-stripping so they don't collide, and test-fit the two pieces before installing either one. To avoid smashed fingers when driving in the tiny nails that secure spring-metal weather-stripping, hold the nails with long-nose pliers. Peel-and-stick vinyl may not adhere well for long, but you can tack or staple it if it comes loose. To reduce tension on spring-metal weather-stripping, flatten it with a block of wood and a hammer. To increase tension on spring-metal weather-stripping, insert a screwdriver under it, pry it up and slide the screwdriver along the strip's length. For greater efficiency, easier installation and less vulnerability to weather and dirt, install plastic films inside wherever they won't interfere with the shades or blinds.