Measure the width and height of the existing window opening at multiple points to ensure an accurate fit.
Order a replacement window that matches your measurements and is suitable for your climate and wall type.
Carefully remove the interior trim using a pry bar and putty knife to avoid damaging the wall or trim.
Use a utility knife to cut through any paint or caulk sealing the window frame to the wall.
Remove the old window sashes by unscrewing or prying them out, depending on the window type.
Clean the window opening thoroughly and inspect for any signs of rot or damage that need repair.
Dry fit the new window in the opening to ensure it fits properly before applying any sealants.
Apply flashing tape along the bottom sill to prevent water intrusion and improve weather resistance.
Insert the new window into the opening from the outside, making sure it sits flush against the sill.
Use a level to ensure the window is plumb and square, then insert shims around the frame as needed.
Secure the window in place using screws through the pre-drilled holes in the window frame.
Fill any gaps between the window frame and wall with low-expansion spray foam insulation.
Apply a continuous bead of exterior-grade caulk around the outside perimeter of the window.
Reinstall the interior trim using finishing nails or screws, touching up paint or caulk as needed.
Open and close the window several times to ensure smooth operation and proper sealing.
