Window Glass Is More Important Than You Think


New windows and doors are an investment in your home, which, if made wisely, increases its value. At the same time, new windows cut your energy bills, increase your comfort, and reduce maintenance cost.


Since most of the window area is glass, its performance obviously has the biggest impact on energy savings. Glass technology has made tremendous strides over the last few years. Things like low conductivity spacers, low emissivity, or Low-E coatings and gas filling have drastically cut the amount of energy that flows through the glass.


Everyone knows that two pieces of glass separated by an air space, and properly sealed on the edges, have more insulating value than a single piece of glass. However, today’s window glass can offer so much more. Low-E coatings represent the greatest advancement in glass technology since the use of two pieces of glass.


Many people believe that the purpose of the coatings is to reduce the fading of furniture and carpeting. While Low-E coatings can do that, the significant advantage that they offer is a drastic reduction in energy loss. Low-E glass has metallic coatings that are a few atoms thick. Technically, these coating lower the emissivity of the glass, thus the name, Low-E. In homeowner terms, it serves the role of a heat reflecting mirror that reflects heat energy from the warm side of the glass back out. In the wintertime, Low-E glass reflects the heat from your home back into the room. In the summertime, it reflects the outdoor heat back out. As a result, its effect on energy consumption is significant. You should never settle for products made with regular clear glass. It’s like buying a car that gets poor gas mileage.


More efficient glass units also use inert gases, like argon and krypton, to improve the energy efficiency of the glass. They are less conductive than normal air, reducing energy losses across the air space between the two panes of glass. It is important to understand that the methods used to trap the gas between the two pieces of glass have a big impact on its insulating abilities and longevity.


Another important parameter that affects the energy savings of an insulating glass unit is the type of spacer that is used between the two pieces of glass. Today’s better products have foam spacers and low conductivity metal spacers in place of aluminum spacers that are fading in popularity.


The latest in glass technology also helps you save energy – physical energy. Special treatments on the outside surface of the glass drastically cut down the frequency of how often you have to clean it.  The better performing units do this by using the combination of a photocatalytic effect and a hydrophilic effect. Marketing as “Neat” glass, it has an invisible, durable and permanent coating of silicon dioxide and titanium dioxide bonded to the glass. The titanium harnesses the power of the sun’s UV rays to loosen dirt. The silicon makes the glass much smoother than ordinary glass so rainwater sheets off evenly and evaporates quickly, taking away the loosened dirt while virtually eliminating water spots.


The last thing, but definitely the most important component to evaluate is the sealant/adhesive that holds the glass and spacer together.  Higher quality units have a dual seal. The one seal keeps the moisture out while the other, which is a better adhesive, bonds the unit together. Dual seal units outperform single seals, significantly increasing the life expectancy of the assembled unit


Obviously, there is a lot more to the glass in your new windows than what you see. In addition to all the glass enhancements, there are many other factors to evaluate when considering an investment in new windows. That is why it’s important for a homeowner to work with someone they trust who walks them through the various options so they can make an educated buying decision.


Bottom line: Take the time to understand what you’re getting for your money. Take the time to look for the investment that gives you all the things you need at the greatest value, not the lowest price. Paying too little can be a waste of money if you don’t get all the things you need and the benefits you want.