How To: Choose windows and patio doors

November 13, 2009

Whether building or remodeling, windows and patio doors are an integral design factor in your project and a reflection of your tastes. They can be practical elements in your home, like garage windows, or they can enhance architectural features, like a living room bay window with transoms. Windows and patio doors serve as a gateway between your protected living environment and Mother Nature surrounding you, so care must be taken in their selection. Today you have a myriad of choices when shopping for windows.

Materials: Raw pine is the most common wood used on interior window sash, frames and panels but customer demand is changing this also, with oak, hemlock, cherry and walnut interiors now being manufactured.

Vinyl products are popular because they are normally affordable, they can be custom-sized to your rough openings for a small nominal cost, and they require little maintenance during the life of the product. Vinyl does not rot, rust, warp or corrode and the multi-chambered extruded frames provide optimal thermal efficiency during harsh winter months. However, vinyl cannot be painted so once you select a color, you will have to live with that color for the life of the product.


If you have your heart set on the warm tones and beauty that only a wood interior on your windows can radiate, look for aluminum, fiberglass, copper, or vinyl cladding on the exterior to cut down on the maintenance. Most American made windows use raw natural pine interiors; although some companies offer cherry, oak, knotty pine, walnut and other premium woods for an upgrade.

Window manufacturers usually offer standard and custom colors of cladding. Your architectural style and budget will best determine what you can select for your project.

Plenty of options: Windows come in many styles and functions: venting and non-venting; double hung where both sashes slide up and down; gliders that slide side-to-side; casements that crank out; and awnings that tilt out. There are also specialty units like bays, bows, garden windows, glass block windows and custom shapes like triangles and trapezoids.

Energy concerns nationwide have made consumers more aware of the glass glazing options available to them. Different glass is designed to help you maintain optimal comfort in your home regardless of where you live.

Research and technology have now given us products that optimize the energy efficiency of our windows. Low-emissivity (Low-E) coatings on the glass, Argon and Krypton gas fillings in the sealed cavity between the two panes of glass, tripane glazing with three panes of glass separating two sealed air spaces and even polyester films permanently suspended between the panes of glass are readily available. The Low E coatings are sprayed on the inside of the panes of glass in the sealed airspace and they maximize heat collected from the sun.

Warm edge spacers between the panes of glass decrease radiant cold transference across the spacer channel, reducing condensation and discoloration on the sash.

Window manufactures now have their products independently certified by the National Fenestration Rating Council (NFRC) against a set of standards of thermal performance. The consumer can easily compare products to see if they meet his energy efficiency needs. Use the U-factor rating to compare products. The lower the U-factor, the better the glazing resists heat transfer and the higher the energy performance.

Minnesota is a pioneer in setting minimum performance standards for windows. You should also check air infiltration rates since they vary widely by product line. Double hungs and gliders must be loose enough to slide in the track so they always have higher air infiltration rates than casement windows. Casements, however, crank out away from the house so they can impede traffic flow in a walkway or get rain on both sides of the sash if inadvertently left open in inclement weather. Because there is so much to consider when purchasing windows for your home, you need to find a dealer who is able to educate you about all aspects of the products.

Condensation: Condensation problems arise because air can only hold a limited amount of water vapor and cold air holds substantially less than warm air. Air, cooled by contact with a cold surface like a piece of window glass, may deposit some moisture on the glass. The moisture on the glass is an indication of the level of humidity in the home, not the quality of the window. Excess water needs to be controlled to prevent discoloration of wood, mildew on walls and ceilings, and water or ice buildup on windows. If your home does not have an air exchanger, it is important to control humidity so you do not have mold growing in your home during the cold winter months when you normally do not have the windows open.

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