How to Install Vinyl Replacement Windows

Updated: Mar. 19, 2024

Save big $$$! Install your own replacement windows. In this article learn about replacing windows.

Next Project

A full day






If you have basic tools and skills you can install your own vinyl replacement windows and save hundreds of dollars in installation charges—for each window.

Tools Required

  • Caulk gun
  • Cordless drill
  • Hammer
  • Hearing protection
  • Level
  • Pry bar
  • Safety glasses
  • Tape measure
  • Utility knife

Materials Required

  • Acrylic caulk
  • Foam backer rod
  • Insulation
  • Shims

Install Your Own Vinyl Replacement Windows

Learning how to install replacement windows looks complicated, but actually requires only basic tools and skill—despite the high prices charged by some window replacement companies.

However, before deciding to tackle the how to install replacement windows job yourself, check the condition of your existing window frames. If they’re rotten or badly out of square, the whole unit, including the frame, may need replacing. This is a much bigger and more complicated job than installing a vinyl window insert and may require a pro.

Project step-by-step (4)

Step 1

Window shopping and how to measure for replacement vinyl windows

shutterstock_272248292 install window retrofit window installation SpeedKingz/Shutterstock

If the frames are sound, the next step in how to replace a window is to measure the interior width and height of each window frame side to side and top to sill. Double-check these retrofit window installation measurements to ensure their accuracy so you don’t end up with a window that doesn’t fit. In most cases, the old frame dimensions will match a standard- size vinyl window. Get to know if you can paint vinyl windows.

Use these retrofit window installation measurements to order the windows from a lumberyard or home center. The price will vary depending on the manufacturer and the features you request. Order windows with insulated glass (two layers). Then consider whether to copy the style (single or multiple glass panes) of the old windows or to change it.

The windows install from the inside. Give yourself at least half a day to install the first unit. Once you’ve learned the steps, the second retrofit window installation will go much faster.

Step 2

Vinyl Replacement Window

vinyl replacement windowFamily Handyman

Vinyl replacement windows come mounted in a new jamb and are simply tilted into the old frame and fastened in place. Here’s a summary of the steps for replacing windows:

  1. Remove and save the inside stop. It’ll be reused in the same place.
  2. Remove the old lower window sash.
  3. Pull out the parting stop. Don’t worry about breaking it; you won’t be reusing it.
  4. Remove the old top sash.
  5. Either remove the sash liners and springs or open the sash pockets and pull out the weights. Remove the sash cord pulleys and stuff the weight pockets with fiberglass insulation.
  6. Push the new vinyl unit into place tight against the outside stop and drive the mounting screws in the sides.
  7. Caulk around the outside and install the vinyl trim pieces.
  8. Reinstall the old inside stop.
Step 3

Close Up of Top Window Section

vinyl window replacement detail how to measure for replacement vinyl windowsFamily Handyman

Top frame cutaway. The inside stop molding helps hold the new window in place.

Step 4

Close Up of Bottom Window Section

vinyl window replacement close up how to measure for replacement vinyl windowsFamily Handyman

Vinyl trim and caulk seal the gap at the bottom of the new window. The window fits against the existing stool on the inside.

How do you decide whether to repair or replace your old windows? Learn your options, relative cost and effectiveness of repairs, and how to judge whether a window should be saved or thrown away.