Residential windows are not complicated when you get down to it. In fact, they only fall into two categories:
1. New construction windows
2. Replacement windows
Not knowing the scoop on windows can cost you. So, you want to be clear on your investment when making your selection.
I am not going to spend a lot of time on new construction windows because the vast majority of homes don’t need them. New construction windows are not reserved for newly built homes. They are called new construction windows because they require the construction of new window framing to be installed. As a result, you can expect damage to be done to the exterior of your home (i.e. siding, stucco).
When installing these windows, expect to pay for the window itself, labor and materials for framing, and replacement/repair of the exterior. It is only when your existing framing is deteriorated or damaged to the extent that it cannot support replacement windows that you should consider new construction windows. Again, this is a rare event.
Most of the time, replacement windows are what you’re looking for. They are nailed into the existing framing in your home and if installed correctly, should be just as effective as new construction windows. You don’t have to worry about damage to the exterior of your home or extra labor and material charges for new framing. As a result, for the remainder of this section of our guide, we will be focusing on replacement windows.
Perhaps more important than the actual quality of the window itself is how it is installed. Even if you purchase the most expensive, highest quality window on the market, it will never achieve what it was designed to do unless it is installed properly.
Make sure that your window installer knows exactly what they are doing before you hire them.
There are entire books dedicated to this topic so, let’s stick to the basics. What determines whether or not a window is energy efficient is debatable, but I always have followed the guidelines set forth by Energy Star. They are the foremost respected authority when it comes to energy efficiency standards and each and every window I’ve provided for my clients has been Energy Star rated and approved. The following are the most important factors that help determine a window’s energy efficient value:
Let’s start with the U-factor and Solar Heat Gain Coefficient. We are going to make this simple. Each window will have values clearly marked on its label.
2. Solar Heat Gain Coefficient
U-factor — measures the transfer of heat by rate, which tells you how well the window insulates. U-factor values range from 0.25 to 1.25 and are measured in Btu/h·ft²·°F. The lower the U-factor, the better insulation value.
Solar Heat Gain Coefficient — measures the fraction of solar energy transmitted and tells you how well the product blocks heat caused by sunlight. SHGC is measured on a scale of 0 to 1; values typically range from 0.25 to 0.80. The lower the SHGC, the less solar heat the window transmits.
As per the number of glass panes in the window (important), I recommend nothing less than two. One glass pane will not be sufficient in most parts of the country and three is overkill. For starters, double pane windows are insulated. The cushion of air maintained between two panes of glass keeps heat in during the winter and AC inside during the summer.
Installing double pane windows will mean a big difference in your energy bills, and keeps you feeling comfortable. Also, double pane glass windows make it very difficult for intruders to enter your home. A single pane glass window is easier to break. Something to think about.
You’ll see many window manufacturers advertising that their windows are the most energy efficient because their windows are indestructible or are the same windows used on NASA space crafts. Most of these are seductive sales tactics and nothing more. Stick to the basics above and don’t get caught up in the busy rigmarole of sales.
Window frames come in a multitude of materials and each can impact energy efficiency, albeit to a lesser extent than the 3 main factors. Below are the various types of frame materials and the pros and cons of each:
– Generally used in commercial applications, aluminum frames are the least energy efficient.
– Moderately energy efficient, wood frames require the most amount of maintenance due to deterioration from weathering. Expect to have to paint them often.
– Referred to as the Goldilocks of window frames, vinyl is the best value when considering its energy efficiency and durability.
– Generally very expensive, fiberglass is the most energy efficient and available in the most amount of colors.
As tempting as it may be to buy common name brand windows from Anderson, Pella, or Marvin much of what you are paying for is the brand name. These windows can be twice as much as lesser-known window brands and, in reality, aren’t any better. Don’t get me wrong, these name brand windows can be great but you can get the same performance from a smaller brand for half of the price. After all, the only person who is going to know the brand of your window is you!