Proper selection of windows for your project will have a major impact on home energy and comfort. Milgard Windows' Guide to Energy Saving Window Features provides information to help you make the right window choice for your home and climate.

SELECTING YOUR WINDOW FRAMES
Today's popular window frame choices are aluminum, vinyl and wood. Consider their features and select the window frame that best suits your home's design and budget.

Vinyl window frames are the latest innovation to conserve home energy. Vinyl (PVC) is a good energy insulator and the hollows in the inside of the frame act as additional insulation. The frames are attractive, require very little maintenance and never need painting.

Aluminum frames are strong without being thick and bulky. They allow maximum glazing area. To improve their thermal performance, consider "thermally improved" aluminum frames, which contain a non- metallic spacer that actually separates the outer frame from the inside frame. This "breaks" the transfer of heat and cold from the outdoors to your home's interior. Thermally improved aluminum frames also reduce condensation on the inside window frame in colder climates.

Wood is nature's ideal natural insulator. Milgard WoodClad™ Windows combine wood's beauty and energy insulation on the window interior, with protective, no-maintenance fiberglass on the outside. Fiberglass will not warp, twist or rot, even in the harshest climates, and offers the ultimate in energy performance.

INSULATED GLASS IS SUPERIOR
Insulated glass is the superior choice over single glazing. Today's energy codes require insulated glass in nearly every West Coast market commonly known as "dual pane" or "dual glazed" glass, the insulation comes from trapping dead air in the sealed gap between two panes of glass. A spacer separates the panels of glass around the edges and the entire unit is hermetically sealed to keep out condensation.
Thickness of an insulated glass unit is often expressed as an "overall" thickness, which measures the air gap plus the thickness of the two sheets of glass. Today, energy conscious window companies like Milgard Windows build insulated glass units that measure 3/4" to 1" overall. Additionally, all Milgard insulated glass units are Guaranteed for life (see your Milgard representative for full warranty information). Insulated glass performance is improved by adding specialty glass, such as Low-E glass, or argon gas to the insulated glass airspace. By using such products, you increase your home's comfort in the winter by gaining a higher indoor glass temperature. In summer, the reduced amount of solar gain results in greater comfort in your home.

WHAT IS LOW-E GLASS?
Low-E glass helps reduce home energy loss. Low-E glass has a special microscopic coating that allows most light to pass through it, while most unwanted heat doesn't. Low-E helps keep the winter heat in and the summer heat out. The sun's energy has three ranges of wavelengths. Ultraviolet, which you can't see, visible light which, of course, you can, and infrared, which we can feel as heat.
The trick is to let in the visible light and keep out the ultraviolet while controlling infrared transmittance according to the season. That's what Low-E glass accomplishes. Its low-emissivity coating lets in 95% as much sunlight as ordinary insulated glass, so your home looks bright and cheery yet it still blocks a majority of the ultraviolet that can fade rugs, fabrics and curtains. Additionally, to ensure year-round comfort, it also blocks most of the long-wave infrared energy, helping to keep winter heat in and summer heat out.
In winter, light and short-wave infrared heat energy from the sun are transmitted. When that energy enters your home and strikes objects, it changes into long-wave infrared heat which the coating then reflects back into your house. The coating also holds in the heat generated by your home's heating system and appliances. So you save on heating bills.
In summer, the coating reduces heat gain by reflecting long-wave infrared heat back outside. That reduces your home air conditioning costs. Milgard Windows features a Low-E coating which is fired on for durability and long life. So its energy-saving properties last as long as the glass itself.

ARGON GAS IMPROVES THERMAL PERFORMANCE
Argon gas is a colorless, odorless inert gas. When pumped into the sealed air space of a window glazing unit, it replaces atmospheric air and gives the window even greater resistance to energy loss through the panes of glass. Argon gas is relatively inexpensive and is a perfect way to economically improve your window's energy performance.
Argon gas in insulating glass has a thermal conductivity that is 30% lower than that of air. By combining Low-E glass with argon, you further reduce thermal radiation through the glass and reduce thermal conductivity, giving nearly double the performance of standard two-pane insulating glass with air.

SPECIALTY GLASS OPTIONS
Living in the Southwest, or with an unobstructed southern exposure often poses a challenge to control the amount of sunlight entering the home. Today, homeowners have the opportunity to select specialty glass types that provide a good "shading coefficient" while allowing enough "visible light transmittance" to naturally light your home with the sun and reduce solar heat gain.
Shading Coefficient for glass describes the amount of solar (heat) energy that is admitted through the glazing. The lower the decimal fraction, the more solar energy is blocked. Clear glass equals 1.0.
Daylight Transmittance measures the amount of visible light that transmits through a window. Tinted glass reduces visible light.
Popular residential tints for glass are bronze and gray. Also popular are reflective tints, such as Solarcool® brand reflective glass. In areas of intense sun, the combination of tinted glass and Low-E glass can provide you the optimum performance when faced with constant glaring sunlight.
Warning for homeowner-applied solar tint films: applying plastic tint films to your windows will void the manufacturer's warranty for the glazing units. Plastic window films cause excessive heat build-up in the glass panels, which could result in seal failure or glass breakage due to solar heat stress.

'U' VALUE: MEASURING A WINDOW'S THERMAL PERFORMANCE
A window's 'U' value refers to its thermal conductivity, that is, the heat flow through the window. For 'U' values, the lower the number indicates the better energy saving performance (how well the window holds in heated or cooled air). Use 'U' value numbers to make comparisons of one glass combination to another.
In sunny climates or exposures, the shading coefficient values are very important to reduce solar heat gain.

WIND AND RAIN PERFORMANCE
To reduce window energy loss, the windows you select must pass stringent testing for air and water infiltration. All Milgard windows are tested according to the high standards set by the American Architectural Manufacturers Association (AAMA).
All Milgard windows pass the ANSI/AAMA 101-88 test, which at a minimum withstand at least a 40 MPH wind with a 8" per hour rain rate with no leakage.

REDUCING OUTSIDE NOISE
Sound which passes through windows is measured by its "Sound Transmission Coefficient" (STC rating). Dual glazed windows have excellent sound deadening properties compared to single glazed windows.
To further improve a window's SK rating, you may consider the use of laminated glass in the insulated glass unit.
Laminated glass is often used in windows near airports or busy streets.

SAFETY GLASS
Tempered glass is used in window and door applications where safety from impact is important. Tempered glass is approximately four times as strong as standard glass. Also, when it breaks, it fractures into very small, dull particles which greatly reduces the chance of personal injury.
Milgard Windows uses the highest optical quality tempered glass available. Consult with your building code official for locations where tempered glass use is required.