Frequently Asked Questions
WINDOW & DOOR PARAMETERS
The basic reasons for windows and doors are to create sources of natural light, ventilation, and accessibility. Too often these basic functions are compromised, and we obtain windows or doors that perform poorly, require too much maintenance, consume too much energy, or totally fail to provide the basic functions. The parameters to be concerned with for both windows and doors are: Functionality, Energy Efficiency, Low Maintenance, Durability, Aesthetics, Warranties, and Cost.
FUNCTIONALITY - Does the window open for ventilation, or is it a fixed or picture window. FIXED windows include sidelights and transoms around doors, special shape windows such as triangles and octagons, and many other non operating windows. These windows are usually the most air tight because the glass is sealed directly to the frame, without reliance on weather-stripping. Operating or venting windows open for ventilation and are available with screens. The SINGLE HUNG window is the most prevalent locally and only the bottom sash opens with the top glass sealed to the frame. The DOUBLE HUNG window allows the upper sash to be lowered also. Double hung units rely on weather-stripping all the way around the window, and would typically have a full, rather than a half screen.
HORIZONTAL SLIDING windows are basically a single hung window laid on its side, with glides or rollers on the bottom, rather than anti-gravity springs (sash balances). While these windows provide ventilation from top to bottom, they are notorious for collecting everything in the bottom track and are usually not very airtight. CASEMENT windows or crank out windows provide the most effective ventilation, and when closed are the most airtight and tamper-proof. They look like a fixed window and do not have the cross bar at eye level, and make excellent choices for over a kitchen sink. Casements allow the complete window area to be opened for ventilation, or easy cleaning of the exterior glass. They can also be utilized to capture even the slightest breeze and deflect it into the home. FRENCH CASEMENT is a twin or side by side double casement, where both windows can be "cranked out" to allow a double wide unobstructed opening without any vertical post in the middle. Some of these double wide casements can both be opened by turning a single crank handle. AWNING windows are basically casement windows turned on their side, and hinged at the top. They provide the same benefits as casements, except as an air deflector, and can remain partially open, even in the rain.
ENERGY EFFICIENCY There are three aspects to energy efficiency. R-Factor, Air Infiltration Rating, and Shading Coefficient. R-FACTOR is the Resistance to heat transfer, and is the reciprocal of U-FACTOR or heat conductivity. R = 1/U (Example R=4 is identical to U=0.25). This is what makes the window feel cold in winter and the one of the causes of condensation on the glass or frame. Unfortunately R-Factor is the most advertised aspect of window energy efficiency, and may not really be THE most important. Also, the R-Factor becomes somewhat meaningless unless it takes into account the entire area of the window, glass, frame, and weather-stripping. An R-Factor for one square foot in the middle of a large window really doesn't convey much, if any, comparison information. It is important to know how the measurements were actually obtained. Be especially wary of "independent test laboratory results". Any prudent manufacturer submitting a product for independent testing will undoubtedly provide a "tuned-up" product for submission to such testing, and the results achieved may vary widely from a production line version of a similar product. The only instance where true comparisons can be achieved is when a manufacturer voluntarily submits to random testing of any production line products by an independent third party tester, who performs standardized testing and certifies the results for each such manufacturer. In the window and door industry, this voluntary organization is the National Fenestration Rating Council (NFRC), to which most of the quality manufactures subscribe. Their results are currently published as U-Factors, which can easily be converted to R-Factors, as above.
AIR INFILTRATION RATING is the number of cubic feet per minute of leakage per linear foot of sash. This circumstance is commonly referred to as drafts, and is the most costly source of energy loss. A relatively small 2 ft. by 3 ft. low quality window can leak as much as 164 cu. ft. of air in a 15 MPH wind. Most homeowners have discovered airborne grit on their window sills on a windy day. The air that has been heated or cooled is literally being blown and /or sucked right out of homes around the glass, weather-stripping and frames. The R-Factor becomes much less important when the air is being exchanged at relatively high rates, and the air that has been heated or cooled within the home is rapidly replaced with outside temperature air.
SHADING COEFFICIENT is the amount of energy that is transmitted through the materials comprising the unit. Materials can conduct, reflect, or absorb energy. A South or West exposure provides significant amounts of the energy spectrum, infra-red (the heat), the ultra-violet (the plant growth and fading component), as well as visible light is streaming onto the glass. With clear glass all frequencies of this energy are allowed to pass through the glass, with minor reflection and absorption. With TINTED GLASS some components of the energy is absorbed, and stored. Some of that energy is then dissipated and reflected to the exterior, and some conducted and re-radiated to the interior, but tinted glass also reduces the amount of visible light passing through the glass. With devices such as SOLAR SCREENS, a high percentage of the total energy is absorbed and prevented from entering the climate controlled space within, with the majority of the energy dissipated to the exterior. LOW EMISSIVITY (LOW-E) glass on the other hand selectively allows the visible spectrum of light to pass through, but reflects both the infra-red and ultra violet providing a much better alternative than either tinted glass or solar screens. Currently the world’s most energy efficient glass is Zo-e Shield, (see additional information about Zo-e Shield)
LOW MAINTENANCE is the amount of effort needed to continuously provide the desired functions over the expected lifetime of the product. If the windows or doors require painting every 4 - 5 years, that expense needs to be included in the overall cost - for the expected lifetime of the units. Also, if the units require periodic repairs, adjustments, replacement parts etc. to maintain their effectiveness, that also relates to the real cost of those units. It is not necessarily the dollar costs relating to maintenance items, it is the amount of time required to research, obtain or schedule repairs or adjustments, and in America today we have a decreasing amount of available time.
DURABILITY is related to low maintenance and anticipates the life expectancy of the product. Most people today replace their automobiles about every five years and there are studies that indicate that Americans now move about once every seven years. How long should we expect window and door products to last, or do we expect to move someplace else before we have to be concerned with that? Is it inconsistent to install forty year shingles on a home with ten year windows? Most windows were procured based on cost to the original builder, not durability, energy efficiency or low maintenance, and today we suffer the consequences. The labor expense of replacing a window or door is essentially the same whether it is with a quality unit, or an inexpensive one, (and the inexpensive to purchase unit, will ultimately cost more over the expected life). There is a saying in the industry that "only the rich can afford a cheap window". When our homes are literally built around the windows, which become sandwiched into the walls, it really makes sense to obtain the most durable, longest lasting product we can obtain.
AESTHETICS or the appearance of the unit may be more important to some people than all of the other parameters. It certainly is true for some areas where the appearance is paramount. True divided lites (TDL), or individual pieces of glass installed in a wood gridwork are the standard in some locales, and many times that is only a single piece of glass, not insulated or dual pane glass. There are also some local areas where insect screens are not used because it is felt that they detract from the home's appearance. Aesthetic concerns are essentially emotional rather than logical, but nonetheless very real, and can assume higher priority than all other parameters. This is especially true regarding front entry systems, and the systems, and the decision-making processes involved in selecting a new or replacement one.
WARRANTIES define how confident the manufacturer is regarding the quality of the product, and how long they are willing to stand behind it. Beware of pro-rated warranties, as they typically have little real value over time. Most warranties cover the product only, no labor. Some manufacturers have only a one year warranty, others have lifetime, with one time transferability. Most do not cover incidental or consequential damages. Some are extremely LIMITED.
COST is a relative term, and is most often confused with purchase price. Real cost is not only the cost to obtain, but also the cost to own - over the expected life of the unit, such as an automobile, with it's expected mileage, maintenance and insurance costs, and future trade in value. it may be fair to say that quality window and door products may cost you nothing. Assume that you are currently expending a certain amount each month due to wasted energy costs, that if reduced could easily pay for the new or replacement products. If the products have a relatively long expected life, once paid for, they could continue to save the wasted energy expenditures for the remainder of their expected life. It would be better to perceive expenditures for quality windows and doors as an investment, with a pay back that typically exceeds that of the stock market. There are very few products that you can purchase, that will, in fact, pay for themselves. We have had documented energy savings of as much as forty percent (40%), merely by replacing drafty low quality window. If you plan on staying in your home for five years or more, it makes little difference which window you purchase at the end of five years you will have expended about the same amount of money whether you purchased quality, or inexpensive windows or doors. The only real difference is whether you paid for quality products with long term benefits and certain pay back, or inexpensive units which incurred higher utility bills and climate control wear and tear costs.