Save Energy: 8 Steps for Window Weatherizing

The average unweatherized house in the U.S. increases the heating bill by 25-40 percent. That difference could be very expensive this year, as anyone who heats with oil or gas knows. Now more than ever, window weatherizing is a chore worth attending to, because with weatherizing you could make up the difference of the current high cost of heating.

The west-facing windows are most likely to catch the prevailing winds, so do them first; the north-facing windows will be exposed to the coldest air, so do them second. The east-facing windows are next. Southern windows, facing the sun, are probably the least vulnerable, so they can wait till last.

1. Can you hear your windows rattle in a heavy windstorm? Yes? Then you have an important weather-stripping job to do. Do little breezes sometimes move the curtains even when the windows are closed? Yes? Then you need both weather stripping and caulking.

Two types of products that are easy to install are rope caulk and V-seal weather stripping. The rope caulk is applied in the fall and removed in the spring. With rope caulk in place, you cannot open the window. The V-seal is applied on the window jamb and enables you to open and close the window while it is in place.

Note from Annie: Once you have identified the air leaks you are going to need to fill them in, and this is where you need to be careful not to add any unwanted pollution into your home from volatile organic compounds in caulking. The caulk that lasts the longest and also has the fewest additives is 100 percent silicone.

2. Do you have some windows that you never open? Consider shutting them with a permanent seal. Close them securely, then caulk around all four sides. Add a single-pane storm window and install a bead of caulk. The end result will be as airtight as the double-pane fixed window you call a picture window in your living room.

3. Cracked panes in your windows, or missing putty around the glass, will let cold air leak through. Get replacement panes for cracked or broken panes and tighten up.

4. Don’t use putty, use plastic glazing compound. Putty dries out, cracks, and falls away. That’s probably why the window needs to be repaired in the first place. A good glazing compound will hold up for at least 10 years before cracking and costs little more than ordinary putty. It’s worth the price.

Take a glob of glazing compound and roll it between your hands until it takes the shape of a piece of rope. Then line it into the wedge made by the glass and the window frame. This makes a better seal than trying to press the compound in a dab at a time. For larger jobs, buy glazing compound in tubes, which can fit into your caulking gun.

5. When installing a windowpane, you can use several kinds of glazier’s tips or points to hold the glass in place. Particularly if you’re up on a shaky ladder, the odds are substantial that you’ll break the pane with your hammer when putting in a pane with some kinds of glazier’s tips. Look for the kind with a nib sticking out. You can catch that nib with a screw-driver, tap the screwdriver handle with your hammer, and improve your chances of success considerably.

6. Getting the glass replaced and reset is the right first step, but a window that is still rattling needs weather stripping. The most satisfactory method is to install V-strips or extruded plastic strips already shaped in a V. If you are weather-stripping many windows, you will save money if you purchase the V-strip weather stripping in 180-foot rolls. Make sure the window channels are free of dirt and grease. Clean with a damp rag before installing the V-strip. and reinforce the V-strip with small tacks.

7. Another area that may be leaking is around the window frame. A bead of caulking compound down both sides and at top and bottom should seal out vagrant breezes.

8. Have you seen those clamshell locks on many double-hung windows? Their purpose isn’t just security but also to pull the sashes together to keep cold air out.