How to Install a Replacement Window in Your Home

Installing a replacement window is easier than you might think. Whether you are installing a replacement window because your old one was damaged, because of a remodel, or because you are trying to cut energy costs, doing it yourself will save you some money.

We just recently installed a replacement window due to a remodel in our home. While installing a new french door, we noticed how much more airtight the room felt. It seemed a good time to replace the old single-pane window in the room to a more energy efficient window while we were doing the remodel.

You probably own all the tools you will need to install a replacement window in your home. Here’s a list of the items you’ll need as well as some tips we learned along the way.

Tools Needed to Install a Replacement Window in Your Home

Tools you probably already own that you will need to install a replacement window include a hammer, a screwdriver (have both flat-head and phillips-head), a tape measure, and a utility knife. You will also need safety glasses, a square or level, a caulking gun (and exterior caulk), 10 penny finishing nails or screws, a pry bar, a broad wood chisel and a drill.

You should also have a reciprocal saw or a saws-all to cut through the nails on the old window. There will be some additional materials you will need such as shims, insulation, flashing tape, insulation or insulating foam, etc. but you will be able to decide on these additional items once you have finalized your window selection.

First Steps to Installing a Replacement Window in Your Home

The first thing you should do when planning to install a replacement window is to decide what type of window you want. Replacement windows come in wood, composite, and vinyl. Visit Home Depot, Lowes, or your local store to decide on your options. Be prepared to tell the salesperson whether your home (and your current window) is brick, wood, or vinyl and whether you want a traditional or a casement window.

You will also need to provide the measurements to the salesperson. These measurements are called the rough opening measurements. You’ll be measuring the width and height of your window at the narrowest point. Measure from the bottom of the inside sill to the top of the head jamb and take three measurements (left, right and middle) for height.

Then measure from the inside jamb on the left to the inside jamb on the right and again, take three measurements (top, bottom, and middle) for width. Use the narrowest measurement of each. If you are unfamiliar with the parts of a window, Lowes has a good picture tutorial here of a window with sills, jambs, and sashes outlined.

Pre-Installation: Removing Your Old Window

When you receive the replacement window you’ve ordered, it’s time to do the installation. Gather all the tools you need because once you start this project you need to finish it. You don’t want to be searching for tools, caulk, or shims. The first thing you will need to do is take out your old window. A note here: it is best to install your replacement window from inside your home. That way you won’t have to chisel out the outer stop of your window.

Remove any facing (trim) so that it isn’t damaged. Also remove the sashes, inside bead, and parting stops. Use your saw to remove the old window, cutting through the old nails so that you can easily remove it. For a video on this process, view Taking Out Your Old Window on Next, cut out any old remaining caulk with your utility knife and clean up remaining edges of caulk with a scraper until relatively smooth.

Using your caulk gun and exterior caulk, put caulk all along the inside part of the outside stops of the jambs. This helps in weather-proofing.

Time to Actually Install a Replacement Window in Your Home

Take the glass windows out of your new window frame and set the frame by itself in opening where you just removed the old window. Make sure it fits and get it level on the bottom and plum on the sides, using shims if necessary. Once it is level and plum, you can pop the glass back in. Nail or screw the window into the existing wood.

Stuff insulation all around the bottom, sides, and top of the window. Or you can use low pressure insulating foam. To see this process, see the Installing Your Replacement Window video.

Finishing Your Replacement Window

Replace the trim you removed earlier. Enjoy your new, energy efficient window.


All About Windows,

Installing Replacement Windows,

Ask the Builder, Taking Out Your Old Window,

Ask the Builder, Installing Your Replacement Window,

DIY Basics, Window, Installing a Double Hung Replacement,

Leave a Reply

Your email address will not be published. Required fields are marked *

one × = 3