Ignoring air leaks around windows and doors is like letting money escape from your home along with your heated or cooled air. Weatherizing your windows with silicone caulk is a straightforward task that keeps your household comfortable and can save hundreds of dollars in energy costs. Below is a clear, practical guide to weatherizing windows before winter arrives.
Windows, whether new or old, need regular attention. Over time, acrylic caulk dries, cracks, and pulls away, allowing drafts to pass through. Replacing deteriorated acrylic with 100% silicone caulk is a smart choice because silicone is weatherproof—resistant to sun, freezing temperatures, and water—so it will last longer and provide a reliable seal.
100% silicone remains flexible and can accommodate joint movement and temperature changes without cracking. It does not shrink, break down, wash away, or yellow easily, making it a superior option for exterior and interior sealing around windows and doors.
Our workshop is in a separate building near our house. It’s a useful space, but insulation isn’t great. This winter we’ll be using it more as we add woodworking tools, so we wanted to stop drafts from wasting heat. Although the windows and doors were in decent shape structurally, years of sun had dried the caulk, causing gaps. The west-facing window, which bears strong evening sun, had particularly dried-out seals.
We chose GE Supreme Silicone Window & Door caulk because it is clear, durable, and formulated to withstand outdoor exposure. While our Southern California climate lacks severe cold or heavy rain, it does have intense sun, so a long-lasting sealant was important for protecting this window.
We weatherized that window in under 30 minutes. The steps below outline the process so you can do the same.
MATERIALS LIST
- Small flathead screwdriver or putty knife and a razor blade to remove old caulk
- 100% silicone caulk (we used GE Supreme Silicone Window & Door)
- Caulk gun
- Paper towels or a clean rag
STEP-BY-STEP INSTRUCTIONS
- Remove the old, hardened or cracked caulk. Use a small flathead screwdriver or putty knife to pry away the larger pieces, and a razor blade to cut and lift remaining caulk for a clean surface.
- Clean the area thoroughly so the new caulk will adhere properly. After removing the old caulk, wipe down the frame and adjacent surfaces to remove dirt, dust, and any loose material. Allow the area to dry completely; you don’t want to trap moisture under the new sealant.
- Prepare the caulk tube and gun. Insert the cartridge into the caulk gun with the push rod fully retracted. Cut the tip of the cartridge at a 45-degree angle to the desired bead size. Pierce the inner seal in the nozzle using the built-in pin on your gun, an awl, or a similar tool.
- Test the caulk flow. Squeeze the trigger and apply a short bead on a paper towel or scrap cardboard to confirm the caulk is flowing and to gauge bead size.
- Apply the caulk. Hold the gun at about a 45-degree angle and run the nozzle steadily along the joint, applying a consistent bead. Move at a steady pace to avoid excess buildup from stopping and starting.
- Smooth the bead. Dampen a finger or a rag and run it along the bead to press the silicone into the gap and smooth the finish. This helps ensure good adhesion and a neat appearance.
- Clean up while the caulk is still soft. Wipe away excess silicone with a damp rag. Silicone products can become rain-ready quickly—GE Supreme Silicone becomes water-resistant in about 30 minutes—but allow a full 24 hours for a complete cure. Keep in mind that temperature and humidity will affect curing time.
Sealing our windows properly gives us peace of mind as the weather cools. Even small improvements to reduce drafts can make a noticeable difference on an energy bill. Caulking a window is an easy, inexpensive project, and with the right materials and tools—like a quality silicone caulk and a basic caulk gun—you can complete the job quickly and effectively.