There are two basic components to a window, the glass and the frame surrounding the glass.
Let's look at window frames first. Frames seal out the moisture and drafts from your home. Today's windows come with frames made from a variety of materials, each of which has their own benefits and drawbacks.
Wood window frames - These are the most common type of frames used in homes. Because wood is easy to work with, it is frequently used in highly detailed designs. These frames can be painted or stained to complement the color scheme of your home and are one of the best insulators. The downside to wood window frames is that they require regular maintenance. Painting these frames regularly can protect against deterioration for hundreds of years.
Vinyl window frames - Vinyl window frames are very energy efficient, and are the least expensive option with virtually no maintenance. However, while they are available in a variety of colors, they cannot be painted or stained and have the texture of plastic, not wood.
Aluminum window frames - While they cannot be painted or stained, they are available in a variety of anodized or baked-on finishes, and are the strongest and most durable of all the frame materials. Aluminum is a good thermal conductor, so in cold weather heat drains out through sash and frame as moisture condenses on the interior surfaces. For this reason, aluminum windows are not very energy efficient.
Composite window frames - These are frames made from more than one type of material so that the manufacturer can make the material fit the task. As an example, the inside of a frame could be made of wood so it can be painted or stained to complement the home's interior design. The outside could be made of a more weather resistant material such as vinyl or aluminum. These frames are more expensive than a vinyl window, but less than a wood frame. The composite frames have excellent long-term durability and are very energy efficient.
Fiberglass window frames - These are very durable and energy efficient frames requiring very little maintenance. These frames can be painted to match your decor and will resist deterioration. However, they are more expensive than frames of other materials. The window industry has a frame and window style to meet your every need. Depending on your priorities, there is a frame that will give you the look you are going for and meet the cost and energy efficient priorities for you and your family.
Many of you have asked, "How can I conserve energy and still have all the wonderful light and beauty that windows let into my dream home?" We all know that glass is not as good at conserving energy as an insulated wall. The most effective method available today to help minimize a window's energy loss is insulating glazing. Insulating glazing typically has two, and sometimes as many as three, panes of glass sealed together in one window. Between these panes either air or argon gas is trapped to act as an insulator. In addition to the insulating glazing, you can further improve the energy efficiency of your windows by one of the following means:
Low emissivity glass - Also referred to as low-E glass, this glass has an imperceptibly thin metallic film which is applied to one of the glass surfaces, or is suspended in between the panes. This lets light in, but prevents some solar rays from being transmitted into your home. This keeps your home cool on a hot day by not letting the heat in and prevents the heat from escaping on a cold day. The coatings also block ultraviolet rays reducing the fading of floors, floor coverings, drapes and upholstery. Windows manufactured with Low-E coatings typically cost about 10-15 percent more than regular windows, but they reduce energy loss by as much as 30-50 percent. (Dept. of Energy)
Tinted glass - Using a bronze or gray cast, tinted glass cuts the glare and heat from the sun, but only slightly reduces the amount of light let into your home.
Reflective glass - Appearing like a mirror from the outside, reflective glass reduces glare and heat from the sun coming into your home.
Windows provide your home with light, warmth, and ventilation as well as a view to the outside world. Utilizing some of the energy-efficient techniques detailed here, you can have both beauty and energy efficiency in your dream home.