How to Install Windows

New windows add to the appearance of your home, make it more comfortable and definitely increase its energy efficiency. Modern windows come as a single unit that can essentially be slipped into place in an existing opening, so installing a window is a job that most handy homeowners can do themselves using tools they already have.

Things You'll Need

• Pry bar (to remove the moldings), level and utility knife
• Shims
• Silicon caulk and caulking gun
• Saw (a power reciprocating saw makes the job easier)
• Hammer and nails (galvanized, 3-inch and 2-inch)

Instructions

Getting the replacement window

1. Decide on your window style. Casement windows are easy to open and close (a crank handle at the bottom), while slider and tilt windows are convenient to clean (the glass usually can be popped out and in).

2. Determine the size of your replacement window by removing the interior trim of your existing window to reveal the rough opening. Measure the height and width of the rough opening and order a replacement window that will fit inside the opening.

Remove the old window

1. Remove the trim (interior and exterior) and cut through any nails (reciprocating saw works best) holding the window in place. If there is a nailing flange on the window use a claw hammer to pull out the nails.

2. Use a utility knife to cut through any caullking around the edges that might be holding the window unit and then lift it out of the opening.

3. Check that the wooden frame is in good shape. If moisture has gotten in and rotted the wood it will need to be repaired before installing the new window.

4. Clean the rough opening. Drive in any nails with a nail set and remove any debris that might be on the frame.

Installing the new window

1. Spread a generous bead of caulking on the bottom sill.

2. Working from the outside, lift the new window into the opening and center it in the window frame.

3. Drive a nail part way in through the nailing flange in the upper right hand corner to hold the window in place, and use a level to get the window plumb and square. Use shims to hold the window in place.

4. Check from the inside that the window operates properly, and fasten the shims in place using 2" nails.

5. Finish nailing the window in place (use 3" nails) by nailing through the flange on the outside.

6. Install insulation (spray foam or fiberglass) around the window in the gap between it and the window frame.

7. Close in the window by installing the trim boards on both the inside and outside.

Tips & Warnings

• Work with a partner if possible. Windows are heavy and installing one is a lot easier with one person on the outside and one on the inside.

• Check the size of your new window when it arrives. Mistakes happen and you don't want to find out your new window is the wrong size after you have removed the old one.

• If you are using spray foam insulation, wear old clothes and follow the directions on the can. Some types are literally impossible to remove once they've dried and if you get any on your hands or your clothes it can be a real mess.