How to Install Retro Windows for Old Wood Single-Hung Windows

Clean the window opening and frame with the hose attachment on a vacuum cleaner to remove any dust or fragments left from the old window.

Pop the framed windowpane out of the new, retro window. This is typically done by squeezing the locking sliders together at the top of the bottom window and pulling the window out. Slide the pane up and free of the window and set it aside. This makes the window lighter and easier to work with.

Lift the window up into the opening. Have an assistant help you if the window is high up or heavy.

Align the window in the opening so the window jambs are flush with the wall and the window sits straight in the opening. Use a straightedge to ensure the window is flush and a carpenter's level to check that it's even.

Drill through each of the pilot holes in the inside of the window frame. This is how you will secure the new window into the opening with a drill equipped with a screwdriver bit. Not all windows have pilot holes, especially if the replacement retro window is wooden. If this is the case, drill pilot holes every 6 inches around the inside of the frame.

Secure the window in the opening by drilling long, anchor screws into each pilot hole.

Push backer rods into the large cracks around the window frame. Work from inside the home. Cut the rods to fit with a utility knife.

Protect the inside of the window frame by applying painter's tape around the cracks on the inside. This will prevent sealant from coming into the home as you work on the outside.

Apply foam sealant in the cracks on the outside of the window with the can's narrow nozzle. Stop before the sealant is flush with the window. It will expand, as it dries, to fill any remaining space. Cut off any excess sealant with the utility knife.

Fill the remaining cracks around the edge of the window with caulk applied with a caulk gun. Inject the caulk into the outside cracks around the window and smooth it out with a damp finger before it sets.