Window Energy Efficiency Tips | The Light Lab

Window Energy Efficiency Tips

Thinking about some Do-It-Yourself (DIY) home improvement projects for your Texas home, but you’re not really sure about what to do or where to start? You’ve come to the right place! Welcome to the DIY Energy Efficiency Tips series from First Choice Power. We’ll show you how to improve the energy efficiency of your home, including hints that make the jobs easier.

Window Energy Efficiency Tips

The calendar may say fall, but it’s still pretty warm all around Texas. But as we get closer to Halloween, night time’s going to start getting a little nippy. That means it’s time to start getting your home ready for winter so you can save money on your electricity bills.

One thing that you should always check is your home’s windows. Thermally speaking, windows (and doors) are usually the weakest part of your home. That’s because window frames and glass (especially glass) don’t provide the best amount of insulation per square inch. A single pane of window glass has an R-value of .9 while just the insulation in standard thickness wall can be R-13. And since a window is really just a hole in the wall that you can open and close, you want to have a window (and door) that closes snuggly and seals out drafts.

Fortunately, there’s a few simple things you can do to get the most energy efficiency out of your windows. We’ll show you what to look for and what to do.

Make Sure Your Windows Seal

If your windows don’t close completely and snuggly, then they’re not going to keep out the cold air this winter. If they rattle or move about easily when they’re closed, then they’re also letting in drafts and moisture. Most newer windows from the 1980’s onwards are equipped with weatherstripping. Over time, weather stripping collects dirt, becomes worn, or tears out. When weatherizing for winter, the easiest job to do first is to clean out window jambs, along the sill (bottom) and across the top to remove any dirt that might prevent the window from closing and also to check out the condition of the weather stripping. For sash windows, check that the sash closes firmly where the bottom meets the sill and the two rails of the upper and lower sash meet. Clean the jambs of casement and sliding windows to make sure they seal firmly. Add weather stripping to areas where you find drafts leaking through.

Self-adhesive foam weather stripping is inexpensive and easy to apply— but it’s not always the right kind. You’ll want the right stuff for the right job.

Find & Fix Window Frame Leaks

Window Energy Efficiency Tips | The Light Lab

Depending on the age and condition of the window as well as the skill of who installed it, air can leak around the window frame. By design, windows (and doors) sort of “float” inside the rough opening and held in place by wooden shims. This is because the wall expands and contracts at a different rate that then window frame. Too tight a fit would cause problems with the window. Still, to keep out drafts, all that empty space needs to be filled with either insulating foam or backer rod foam and sealed over with silicon. If it’s not done right , not only will cold air get in but it could also lead to water penetrating the wall of your home and causing problems with rot as well as pests.

If you notice drafts or mold growing around the edge of the window or door frame inside your home, then you may have a frame problem. The fix is to remove the inside trim molding and to inject non-expanding insulating foam all the way around the frame. If feasible and safe, you also might want to do some sealing with foam or caulk from the outside. Also keep an eye out for places where rain run-off might be penetrating the sheathing around the window. Seal any little gap you might find with silicon caulk.

Window Glazing Problems

Most newer double and single pane windows aren’t made the same way old single paned windows are. Old single paned windows usually have their glass held in place with glazing putty which can contain talc, powered limestone, and any number of petroleum solvents. Glazing putty goes on easily and hardens slowly, but it can last decades. However, when it begins cracking and breaking off, it must be replaced. Glazing needs to be done right but it can be tricky. Keeping the angles and corners neat and clean preserves the window’s look and it takes some practice to master the techniques. That said, if you don’t have time to work on either, you can use silicon caulk.

How to Replace Window Glazing in 3 Steps

1) First, scrape out all the old glazing and clean out any crumbs of debris.

2) Insert glazing points to secure the glass in place (as needed) and then lay down one or two beads of silicon to seal the glass.

3) Lastly, get a good finished seal on the caulk by wetting a finger tip and lightly wiping it along the top of the wet caulk. This pushes the caulk deeper into the joint. It takes a good deal of practice to develop the technique and avoid getting caulk all over your hands.

Window Condensation Problems

Window Energy Efficiency Tips | The Light Lab

If your windows have condensation on them during cold weather, there are two very likely causes: either there is too much moisture inside or cold is leaking around the window some where and condensing on the glass. Single paned windows are more prone to condensation than double glazed insulated windows. If the window frame is metal or uses internal metal parts to open or close it, the metal could be conducting cold inside where humid air condenses on it, causing water damage. If you can’t find a cause right off, try reducing the humidity in your home such as running ventilation fans while showering or cooking, and check that clothes dryers and fully vented outside.

Curtains & Window Treatments

If you’ve ever stood in front of a window when it’s 30°F outside, you can feel the cold pulling the heat from you. The same thing happens to the air in your home. However, curtains and drapes help keep a room warm by reducing the amount of air flow over the cold glass. In fact, insulated curtains reduce a room’s heat loss by 10% in the winter. You can actually squeeze out a little more performance from a window treatment by topping it with an air-sealed valance to reduce air flow even more. Should you open the curtain during the day? Yes! Of course, especially those on the south, east, and west facing windows since they will let in the warm sunlight. For those on the north side of your home, keep the drapes closed on really cold days.

New Window Terms

Window Energy Efficiency Tips | The Light Lab

If you’re in the market for new energy efficiency EnergyStar approved windows, two important terms you need to understand are “U factor” and “Low E”.

Heat travels through different materials at different rates. Insulation, for example, has R-values, which measures how well the insulation resists heat being conducted through it. Because each window is made of several kinds of materials that includes glass, glazing, and frame, windows are rated in “U-factors” to measure how fast heat moves through entire window frame — both from the inside or the outside. Most low-U windows are double-glazed (two sheets of glass) and contain an inert gas that acts as an insulator. The lower the U-factor, the better slower the movement of heat and the better the performance.

“Low E” refers to a thin coating on the glass panes that reduces conduction from the hot sun’s rays. This improves the window’s U-factor by substantially reducing energy loss by up to 50% —BUT Low E windows cost about 10% more.

Consequently, when you’re planning on energy efficient windows, the smart thing to do is to only use Low E windows on those that will receive the most amount of sunshine during the day. That means you’d only put Low E windows on the south and west facing windows while your northern and eastward facing windows won’t need the Low E coating. Not only will you save money by saving energy, you’ll also save by using the right kind of window in the right place.

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Vernon Trollinger is a writer with a background in home improvement, electronics, fiction writing, and archaeology. He now writes about green energy technology, home energy efficiency, the natural gas industry, and the electrical grid.