Old, drafty windows aren’t just an annoyance. They make it difficult to keep your house warm in the winter and cool in the summer, increasing your electric bill in the process. Replace a window and you’ll add value to your home. It’s also something you can do yourself in a single day. Here’s what you’ll need to take on this project.
TOOLS & MATERIALS
- Tape Measure
- Utility Knife
- Power Drill/Driver and Impact
- Flashing Tape
- Replacement Window
- Wood Shims
- Insulating Foam Sealant
- Foam Backer Rod
- Exterior Caulk and Caulk Gun
- Pry bar and Mini Pry Bar
- Putty Knife
- Paint Brush
- Vacuum (optional)
- Step Ladder (optional)
- Ladder (optional)
- Nitrile Gloves (optional)
When taking on this DIY task, be sure to equip yourself with the proper safety gear.
- Ear Protection
- Eye Protection
Remove trim. Use the utility knife to score any paint or caulk along the edges of your window trim. This will help prevent damaging wall paint as you remove the trim. When you finish scoring, use a prybar and hammer to remove the trim until it’s completely removed.
Measure the window. Your replacement window will need to fit inside the existing window frame. To determine the correct measurement, measure the width and height from the outside of the frame on all sides. Your new window will be slightly shorter and narrower than your current window. Most manufacturers subtract about half an inch from both dimensions.
Remove stops. To remove side stops, tap a flat bar underneath it and pry up slightly. Add another flat bar and pry up a bit more. Make your way down the bar slowly as you work the stop away from the frame. Once you remove the stop, pull out any finished nails left behind. Remove the fastener holding the stop in place and take out the bottom part of the window.
Remove old window. Continue removing stops until you can slide the top part of the window out. If your window has sash weights, disconnect the rope or chain and let the weights fall into the wall.
Remove frame. Use a prybar to pull off any flashing or old caulk around the exterior of the frame. Remove nails or screws holding it in place. Take the frame out and clean old caulk with a hammer and putty knife.
Apply flashing tape. Although you’ll be caulking your new window, flashing tape provides an extra barrier against moisture. Make sure the old frame, including the sill, is free of debris, then cut a piece of tape 12 inches longer than the width of the window. Butt the tape against the outside of the window stool and extend it six inches above the sides of the existing frame.
Prep window. Remove packaging. Lift and remove the bottom windowpane and disconnect the spring balance. Repeat this process for the top windowpane. Remove the jamb liner, then pre-drill three locations along the center of each side of the frame: one at the top, the middle, and the bottom. Some windows come with an installation flange. If yours does, install per manufacturer’s instructions.
Position new window. With a helper, and checking for level as you work, lift the new window into place, resting the outside of the window’s top and sides against the exterior stops.
Attach new window. Confirm the window is centered, place shims behind each pre-drilled hole, and insert screws. Start at the top corner on one side, then screw in the bottom on the same side, checking to make sure the window’s level as you work. Repeat on the other side, this time securing the bottom then the top. Measure at the bottom, middle, and top to ensure your installation is straight. The measurement should be the same. Secure the middle on both sides, once again confirming the installation is level.
Reassemble your window starting with the jamb liner, followed by the top windowpane, then the bottom windowpane, hooking each into the balance as you go. Make sure the window operates smoothly. If it doesn’t, you may have to back out a screw and loosen a shim that is bowing the new frame. Once you’re satisfied with your installation, trim the shims by scoring with a utility knife and snapping them off. Then, remove remaining shims.
Caulk exterior. If the gap between your old frame and new frame is more than a quarter inch, you’ll need to install a backer rod before caulking, and if necessary fill any gaps between the frame and foundation. To do this, rip and fasten pieces of wood, adding aluminum-coil stock if needed. When complete, apply a bead of exterior caulk around gaps of the side, top, and where the new frame meets the old sill at the bottom, smoothing the bead with your index finger as you work.
Insulate between frames. Your last step is to insulate between the new frame and the old frame. It’s important to use insulating foam sealant for this task as latex or high-pressure foam could distort the new frame. Apply a bead of foam into the cavity. Since the foam will expand, keep the bead about one inch from the exterior side of the opening. If the foam expands beyond the interior of the frames, trim it flush with a knife after it sets.
Your installation is complete. To complete your trim, check out our “How to Install Window Trim” and “How to Install Farmhouse Window Trim” tutorials.