How to Retrofit Windows

a window
  • 5-10 hours
  • Advanced
  • 300-1,000
What You'll Need
Window trim
Insulation material
Caulking and caulk gun
Retrofit window

Your home can easily be upgraded and made much more energy efficient by upgrading your windows and using new retrofit windows. If you have old aluminum windows in your home, then these may not be able to provide your home with the insulation that it needs. Retrofit windows can be installed to make your home much more efficient, and also to improve the look of the windows. Retrofit windows are actually very easy to install and fit.

Retrofit windows make it possible to fit new vinyl windows in much older style aluminum frames. This means you can benefit from the energy efficiency without needing to fit new window frames.

Anybody who is competent at DIY and has the right tools and materials available will be able to install retrofit windows easily. You should be able to complete the project in around a day.

Step 1 - Measuring

Measure the opening inside the window frame. Remember that the aluminum window frame will be left in place so do not measure the entire opening of your window.

To work out the width you need to measure in-between the metal legs and take off 1/2 an inch. Measure the top to bottom in the same way and deduct 1/4 of an inch.

Step 2 - Removing Panels

Remove the old window panels, both sliding and stationary panels at this point.

WARNING: Make sure that you wear gloves when removing glass panels because there is a chance that they will shatter and cause you harm.

Step 3 - Caulking

Once you have removed the window panes you then need to run a large amount of caulking around the window frame on the outside of your building. This is what the retrofit window will stick to and they will secure the frame to the window frame.

Step 4 - Fitting the Window

Place the retrofit window into the opening from the inside of the window. Use a spirit level to ensure that the window frame is square and level. Open the vent panel to check that the window frame is perfectly square. If the window needs leveling then you can use packers to make this possible.

The retrofit window frame then needs to be screwed in place, be careful not to tighten the screws too much because this can cause damage.

Use caulking to seal around the screw heads in the window so that the window frame is completely weatherproof.

Step 5 - Finishing Touches

From the outside run a bead of caulking around the frame where it meets the brick work of the house. This will seal the gaps and prevent water from getting inside.

The gaps on the inside of the frame should be filled with insulation material which is packed right into the void. Then use wooden trim to conceal this. Use caulking again to hide the gap between the wall and the trim.