- Popular window styles include the single and double sash, the sashes being the movable sliding parts. Single-sash windows are cheaper; double-sash ones are more versatile as they allow you to open either the bottom or the top. Both types are prone to leak in cold, windy weather. Casement windows are the kind that open either inward or outward, usually using a crank. They tend to be more energy-efficient, but the hardware and the position of the window when open may prove to be inconvenient. Jalousie windows operate somewhat like venetian blinds, only the "blinds" are actually slats of glass that are part of the window. These tend to be used in warm-weather-only areas, as they do not work too well at keeping the cold weather out. Other window styles you may wish to consider include the multi-paneled bay window, the non-opening fixed window or even the decorative stained-glass window.
- Aluminum window frames are light, strong and easy to clean, but not energy efficient and are prone to condensation. Fiberglass window frames are also strong and low-maintenance, highly energy-efficient, but they do tend to be expensive so may not be an option if you have budget constraints. Vinyl window frames are affordable, efficient, durable and low maintenance, but they cannot be painted, which limits your color choices. Wood window frames are perhaps the most attractive type of frames available. They are durable and efficient, but they do require a good deal of maintenance (staining or painting). They also can be expensive.
- Clear glass is the most affordable type of glass available; it does let in the greatest amount of light. Tinted, or heat-absorbing glass, is usually colored gray or bronze, sometimes blue or green. It may be a good choice if you live in a hot and sunny climate, as the tint helps to cut down on the total amount of sunlight that enters the house. Reflective glass is another good choice if blocking excess heat and light is a concern. Low-emissivity (low-E) glass has a special coating that can help block heat from either entering or leaving a house, depending on which side of the pane the low-e coating is used.
- Single-paned windows are the cheapest, lightest and easiest to repair, but they permit the greatest amount of heat to escape, which will result in much higher utility bills unless you live in a climate that is temperate year 'round. Double-paned windows can be insulated with low-E plastic between the panes, but triple-paned windows with an inside layer of low-E glass are the most energy-efficient type. You will need to calculate whether the savings on your utility bills are likely to offset the much higher cost of these windows.
- ENERGY STAR windows are ones that have been certified by the Environmental Protection Agency's ENERGY STAR program as being energy efficient. ENERGY STAR windows have low-E glass, multiple panes of glass and frames that provide extra insulation. The EPA estimates that the average household can save from $126 to $465 per year by replacing clear glass single-pane windows with ENERGY STAR windows, and save from $27 to $111 per year by replacing clear glass double-pane windows.
