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Many property owners in Dallas, TX spend a significant portion of the household budget on cooling costs, which could be partly due to their windows. Unfortunately, old windows let air escape the house, and drafts push hot air into the home. This forces air conditioners and other cooling systems to work harder to maintain desired indoor temperatures. Insulated walls or attics increase a structure’s overall energy efficiency, but up to 20% of external air entering a home comes through windows.
Replacement windows are a major investment for most property owners. The long-term energy savings and other benefits are worth the initial cost when appropriate replacement windows are installed. Characteristics of ideal replacement windows depend on climate, the home’s structural characteristics, and personal style and preferences.
Watch for signs that indicate windows are wasting energy. Check for cracks in window frames or between panes if HVAC systems seem to be working harder or working more often. Pay attention to drafts in the home and
find out if they are coming from windows. Condensation on windows is a sign of energy loss and indicates high humidity inside the house. Energy-efficient replacement windows provide a clear view without condensation, and homes in Dallas, TX are more comfortable with lower indoor humidity.
Pay attention to temperature differences between rooms. Rooms that are consistently warmer than the rest of the house may have air leaks and cracks around windows. Water leaking in around windows is a sign that the windows and frames need to be replaced quickly. Water leaking into the home can lead to structural damage and mold.
Be aware of noise levels inside the house when sounds come from outside sources. Outdoor noise should be muted inside homes. Replacement windows are necessary when windows are hard to open and close. Warped frames cause windows to stick, and the glass could shatter when windows do not open or close smoothly. Warped frames also let air move in and out of the house through gaps around windows.
What Are Window Performance Ratings?
The National Fenestration Rating Council, or NFRC, and ENERGY STAR® provide window performance ratings. The NFRC certifies skylights, doors, and windows according to energy performance. Manufacturers voluntarily choose to have their windows and other products tested and certified. The ratings help homeowners choose the best products to meet their needs.
Window performance ratings describe the window’s properties and abilities. Ratings include measurements such as the U-factor, solar heat gain coefficient, and visible transmittance. ENERGY STAR® is a government program that rates
windows on U-factor and solar heat gain coefficients. All ENERGY STAR windows also include a NFRC label, however, windows with NFRC labels may or may not be ENERGY STAR® certified.
The U-factor provides information concerning how quickly a window conducts non-solar heat from outside air into the house. The U-factor rating falls in proportion to the windows insulating value. A low U-factor rating means the window transfers heat at a slower rate than windows with high U-factor ratings. The solar heat gain coefficient, or SHGC, describes how much solar radiation can pass through a window into interior space. The SHGC is noted as a number between 0 and 1, and lower ratings mean that less radiation passes through the window.
Visual transmittance, or VT, refers to the amount of light transmitted through a window. VT ratings range between 0 and 1, and VT ratings rise in proportion to increased light transmission. (VT) describes how much light is transmitted
through the window. The higher the visible transmittance rating, the more light gets through. Most windows have VT ratings between 0.3 and 0.7.
Air leakage, or AL, ratings indicate how much air enters the interior of a room or building through the window. AT ratings are measured as the number of cubic feet of air able to pass through a square foot of a window’s area. Basically, lower AL ratings mean less air leaks through cracks in the window frame.
Condensation resistance, or CR, indicates a window’s resistance to moisture and condensation on interior surfaces. CR ratings are measured on a scale of 1 to 100. Higher ratings mean the window has greater resistance to moisture and condensation is less likely to form on inner surfaces. CR is not a mandatory rating for NFRC labels, so it is not available for every NFRC- certified product.
Choosing Replacement Windows in Dallas, TX
Weatherstripping windows decreases energy loss, but it is only a short-term solution. Replace old windows with new energy-efficient replacement windows for permanent energy savings and other benefits that weatherstripping can not provide. Energy efficient windows also act as sound barriers and absorb noise. Property owners in Dallas, TX, need to evaluate replacement windows for performance in a warm, sunny climate.
Whole-unit U-factors and SHGC ratings are more useful for evaluating performance than center-of-glass U-factors and SHGC ratings. Whole-unit measurements describe the performance of the entire window and frame, but center-of-glass ratings only describe glass panes. NFRC-certified windows always take the window frame and glass into account.
Energy efficient windows allow less direct sunlight to enter the home than older windows. Direct sunlight adds heat to rooms through passive solar heating. Many energy-efficient windows have coatings to reduce heat transference.
Some energy-efficient replacement windows also have special coatings or tints to filter sunlight to reduce solar heating and block ultraviolet light that damages furnishings and carpet. Cooling systems work harder and use more energy when they have to compensate for excessive sunlight and heat, especially if sunlight raises the temperature in multiple rooms.
Most homes and other buildings in Dallas, TX benefit from windows with low SHGC ratings because air conditioning and cooling are the greatest concerns in hot, sunny weather. Property owners should take each window’s position and the orientation of a building or house in proximity to shade trees into consideration as well.