How to select high performance windows for your home

How to select high performance windows for your home

Heating and cooling costs are a big part of household's budget. According to Energy Star, the Environmental Protection Agency's energy conservation program, the average American household spends more than $2,200 a year on energy bills, with nearly half of this going to heating and cooling costs.

You can take control of those costs by using high-performance, energy-efficient windows in your home. These windows, which are available for both new construction and replacement use, will help cut utility bills and make your home more comfortable.

Selecting windows can be an intimidating task. There are many different types of designs, finishes and glass coatings, not to mention different styles and colors.

A high-performance window is one that provides a high level of insulation and air sealing and heating in the home. The worn out windows in an older home are a good example of bad windows. The single pane of glass does not provide much insulation, and may become covered in condensation in the winter. The worn out frame and sash may allow air to leak through even when the window is closed.

Even in a home that's 20 or 30 years old, window technology and building science has advanced so much that those windows should be replaced with new ones. In a new home, the windows can play an important role in its design and performance.


Look for new windows that bear the Energy Star label, which ensure they are better than average in performance. Windows today can far exceed Energy Star requirements that make the a great fit for homes designed to meet a green building standard such as LEED or Passive House or National Association of Homebuilders ICC700 National Green Building Standard.

First, visit www.energystar.govto determine your home’s Energy Star Climate Zone. Then, find a retailer or manufacturer of Energy Star qualified windows, doors or skylights at the Energy Star website or by looking up information directly on a company’s website.

Be sure to ask for Energy Star qualified windows when placing your order. Whether you’re in a showroom or meeting with an individual window installer, make sure you request ENERGY STAR qualified products for your home.

For windows, doors and skylights, the Energy Star program makes sure each product is independently certified to perform at levels that meet or exceed energy efficiency guidelines set by the U.S. Department of Energy.

The National Fenestration Rating Council (NFRC) provides the certification for windows, doors and skylights for Energy Star. NFRC is a non-profit organization that administers anNFRC labelindependent rating and labeling system for the energy performance of windows, doors and skylights. This program helps homeowners compare different products and make informed purchasing decisions.

The majority of windows and doors manufactured have an NFRC label. This label will not tell you which window to purchase, but it can be a valuable tool (much like the miles-per-gallon sticker on a new car).

The NFRC testing protocols involve testing of the full window, door or skylight --- including glass, frame, spacers, and any other component --- that is a permanent part of the complete product.

This strategy provides you with a more accurate reflection of how the product will perform in the home than testing of just glass, as the framing and other components influence ratings such as U- factor, Solar Heat Gain, and Visible Transmittance.

The NFRC Label is the only window label that provides certified energy- related performance ratings that are acquired through independent testing of the product.


Compare the full-frame R- value of windows to find the choices with the best insulation capabilities. R-value is a measure of thermal resistance used to compare insulating values through any partition. The higher the R-value of a material, the better the insulating properties.

An average insulated wall is approximately R-13, while Energy Star- rated windows are approximately R-2 to R-3 (varies according to climate zone).

Now many window manufacturers, including Ply Gem, offer windows with an R-5 or above rating. These windows offer significant energy savings compared to the R-3. The DOE reports that increasing the R-value from 3 to 5 reduces average heat loss through the windows by 30 percent.

Frame Material

Window frames come in a variety of materials, including wood, aluminum, composite, fiberglass, and wood clad. These materials have different insulation characteristics.

Ply Gem’s windows incorporate advanced technology for better performance

Warm Edge technology: The windows incorporate a spacer system that reduces heat transfer around the glass perimeter by using a U-shaped channel. The channel is a continuous pieces that separates glass panes to interrupt the natural flow of heat to cold.

R-CORE® Insulation: Ply Gem uses a patented high-density solid polyurethane insulation similar to that found in many refrigerator/freezer doors. Depending on the package, R-Core can be used in the frame and sash.

Glass Coating

Low-E glass: Low-E (low emissivity) glass has a secondary, very thin metallic dual layer coating. Heat and light from the sun pass through the insulating glass, but also reflects radiant heat back toward its source. Low-E coatings help keep your home warmer in the winter by trapping radiant heat and cooler in the summer by blocking it from your home.

Gas Fill

Argon gas fill: A colorless, odorless non- toxic gas, argon provides insulation between panes of glass. It's about 40 percent more dense than air, blocking the flow of heat and cold.

If you’re building a home or looking to remodel your current residence, high performance windows are a good investment in energy saving and comfort.

Read more about energy efficient windows and doors.

Topics: Building Green, Doors, Energy Star, Exteriors, Maintenance & Repair, Remodeling, Windows

Companies: U.S. Department of Energy

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