Note from Michael: This article was contributed by Scott Gray.

Choosing the right replacement windows can dramatically improve the look of your home, save you big money on heating and cooling costs, and make your home less drafty and more comfortable.

Which types of windows are best? Windows come in a variety of styles and materials. Understanding the drawbacks and rewards of each type can help you to make a sensible, informed decision that results in real savings.

New windows can be custom made to any specification for any purpose, but some shapes and designs are standard. They can even be purchased off-the-shelf at home improvement stores, which will save you some money.

Window glass can be double or triple hung, and can include specialty features meant to keep heat in or out depending on the season. Shapes and styles can be traditional and familiar, or custom-designed for specific purposes.

Types of Replacement Window Frames

Any style of replacement window can be framed up with aluminum, fiberglass, vinyl, wood, or some combination of these materials. Framing materials have a major impact on the energy efficiency of replacement windows, and also affect their cost.

• Aluminum. Aluminum framed replacement windows are the most affordable but also the least efficient. Their clean lines make them popular with architects for ultra modern construction. In the winter, condensation on the window frames can cause issues with mold and dry rot in some parts of the U.S.
• Fiberglass. Comparable to wood in efficiency and cost, fiberglass window frames have a clean, fresh look, are moderately energy efficient, and have the advantage of being very lightweight and easy to handle.
• Wood. Wood framed windows are required for historic upgrades in some parts of the country and are heavier and pricier than vinyl or aluminum. Vinyl clad wood is a popular high-end choice for optimal energy efficiency and durability.
• Vinyl. By far the most popular choice for replacement windows. Vinyl is energy efficient, affordable, and looks nice with the vinyl siding that is now featured on most homes. Vinyl is easy to maintain and looks new for years.

Window Glass And Other Considerations

Window glass can be double hung or triple hung. This refers to the layers of panes of glass used to increase thermal efficiency. Glazing on window glass often includes special features like tints that adjust to the amount of sunlight, or reflective coatings that keep heat in during cold weather and out during warm weather.

Some window glass is coated with a very thin layer of polyester or metal that makes the surface slightly reflective, like a mirror. Reflective glass also helps to keep heat in during the winter months and out during the summer months. Choose the glass options with the highest insulation value you can afford.

Single pane glass is hard to find and no longer recommended. The dead air space between panes of double or triple hung glass is what provides the insulating value that saves energy and keeps the house more comfortable.

A perfect vacuum between panes carries the highest insulating value, but glass has to be very thick to withstand a perfect vacuum between panes. For this reason, various gases are used between the panes to increase the insulating value.

The most common gas used to boost insulation between panes is argon, which conducts heat 67% as fast as oxygen and so keeps the house warmer in winter and cooler in summer. Krypton gas is sometimes used to help insulate between panes of specialty windows that are very thin. Xenon gas is used only rarely since it is very expensive.

When shopping for new windows, always look for the Energy Saver label. This label indicates that the windows are environmentally sound and are eligible for an Energy Saver tax credit for the year you install them. According to the U.S Environmental Protection Agency, choosing Energy Star replacement windows can save the average household up to $476 per year in utility costs when installed in place of older, single-paned windows.

About the Author:
Scott Gray is a handyman enthusiast and web publisher. He enjoys providing tips to consumers and homeowners about do it yourself home improvement projects, glass vessel sinks for your bathroom and reviews about cordless drills.

Added note from Michael: Scott mentions vinyl (PVC_ as being a popular choice, but it's good to also be familiar with the environmental impact of PVC before settling on the type of framing you select bearing in mind your needs and budgetary constraints.