Insulation in the attic and walls is vital to making your home more energy efficient, but that’s not the whole equation. The other, very important part of the equation has to do with the other major portion of your home’s exterior: the windows and doors.
The efficiency of these components can dramatically affect your cooling and heating costs. In the summer, controlling the amount of heat entering your home will help your AC run less and make your home more comfortable. Conversely, in the winter, reducing the amount of heat escaping from the home will save you money on heating and make the home more comfortable.
According to the National Association of Home Builders, the average home today has nineteen windows and doors, the larger the home the more doors and windows. Windows and doors therefore make up a large portion of a home’s envelope. Adding insulation to your attic and walls makes no sense without addressing the quality of the homes windows and doors.
Remember, the warm air always tries to transfer to the cold air, so in the summertime, the hot air outside your home is trying to get into the home while in the wintertime, the warm air inside the home is trying to transfer to the cold air outside the home.
Windows and doors account for almost half of your home’s heat gain in the summer. Inspect weather stripping around doors and window to ensure cracks are sealed and air isn’t leaking into your home. Caulk around window frames and all exterior wall penetrations such as pipes, electrical boxes and vents.
One housing component that has truly evolved and made significant advancements in building science are windows, particularly in the glazing components used on glass and the framework around the window.
As a home buyer out looking for a home for you and your family, you will typically come across three different categories of windows. First, most older homes available in the resale market, that have not made upgrades to their windows, will most likely have single pane windows with an aluminum frame.
The big issue with single pane windows is that heat can easily transfer through the pane and therefore heat can easily enter your home in the summer and escape in the winter. This is therefore a source of higher heating and cooling costs and it becomes a source of discomfort when trying to utilize particular rooms in the home. Rooms that have large window and glass exposure with single pane glass can become very warm at certain times of the day in the summer and can become very cold and drafty in the winter thereby forcing the people living in the home to adjust their lifestyle.
It can be perplexing when trying to understand why a room feels drafty in the wintertime. You typically will check around the window frame to make certain that air is not passing through cracks and that the window is properly sealed. After inspecting around the frame you determine that the window is sealed just fine but you still feel a draft. So, where does this draft come from?
The draft comes from convection. If you put your hand on the window in the wintertime, the glass will feel cold. When the warm air in your house hits the cold glass, that air cools. As you know, heat rises and cold sinks. So, the now-cold air drops toward the floor, and the warmer air rushes toward the cold window glass, creating an airflow pattern that you call a drafty room and increases your heating bills and your energy usage.
In new homes and retrofits, window frames have evolved from aluminum framing to vinyl and fiberglass components. The fiberglass used in the past on window frames tended not to handle extreme weather very well and was prone to cracking and wearing out quickly giving fiberglass frames a bad reputation. The newer fiberglass frames are of much better quality and weather very well.
The vinyl frames tend to be less environmentally friendly as the process used to make the polyvinyl chloride (PVC) is a highly toxic process. Most new home builders will use either the vinyl or fiberglass frames to encase their windows. Both of these are very durable and require very little maintenance.
The most environmentally friendly or green material used to frame window is wood. Wood frames have their benefits however they do tend to require more care and maintenance over the years as they do not hold up to extreme weather as well as the fiberglass and vinyl frames.
The next upgrade to window science is in the glass and the addition of a second pane, many dual pane window are filled with argon gas which results in far less heat transferring through the window which of course reduces the amount of energy needed to keep your home comfortable and thereby lowers your utility bill.
That second pane of glass can make those hot summertime rooms and those cold and drafty wintertime rooms become more livable and enable you to enjoy your home at all times of the year while yet again saving you money.
The latest advancements in window science has taken us from the old single pane / aluminum frame windows to the fiberglass / vinyl, double pane windows to the newest energy efficient windows which are called Low-E windows, Low-E 2 and Low-E 3 windows. These are basically a combination of all the advancements and provide extremely good insulation.
Low-E coatings on windows reduce energy consumption by as much as 30-50% compared to regular windows. Low-E windows reflect heat and thus help to eliminate the winter drafty room problem. Low-E coatings, which are microscopically thin materials bonded to the surface of a window’s glass, are so thin you can see right through them yet prevent heat and ultra-violet (UV) rays from passing through the glass. The additional benefit of blocking the UV rays is important because the UV rays can fade your furniture, your pictures, your carpeting, and even your wood flooring and cabinets.
When considering the HERS Rating of the home it is fair to assume that a new home with a HERS score of 100 would probably have double pane vinyl windows, an older home with a higher HERS score would probably have single pane / aluminum frame windows and an energy efficient green home would most likely have Low-E 2 or Low-E 3 windows.
The U.S.Department of Energy says, “About 15 percent of the average home’s wall space is made up of windows. If those windows are old, loose and leaky, they can account for 25 percent of a home’s energy usage.”
So, when you are out shopping for your next home, it is important to compare apples to apples by understanding the value involved in a home with upgraded windows or the potential costs you will incur in upgrading your windows down the road.
Changing your windows from single-pane to double-pane models is not inexpensive. You can expect to wait ten years to recoup your investment if you’re switching over for energy-saving reasons. Of course, you do reap the benefits of a quieter and often cleaner, more dust-free home right away along with increasing the value of your home.
On the other, if your windows happen to be broken or leaking, you can expect a much faster payback: in the neighborhood of just one to two years.
The Energy Star folks help to put some numbers to this. According to them, for a typical home, switching to Energy Star-certified windows can help reduce your energy bill by as much as 15 percent. In dollar terms, they say the switch can save you $126 to $465 a year when replacing single-pane widows and $27 to $111 a year over double-pane, clear glass replacement windows. Not surprisingly, your savings are going to be the most dramatic if you live somewhere with really hot summers, really cold winters, or both.