Installing retrofit windows involves placing new windows into an existing frame without removing the old one. Measure the existing window opening and order the correct size. Remove the old sash, apply caulking, and place the new window into the frame. Secure it with screws and seal the edges with caulk to ensure proper insulation and a clean finish.

Retrofit windows are installed without removing the existing frame, making it a quicker and less invasive process. Proper sealing with caulk is essential to ensure energy efficiency and prevent air leaks. This method is ideal for replacing older windows without extensive renovations.