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The cooling results brought another surprise in projecting only tiny energy savings for the storm windows or non-low-e replacement windows. This occurs because reduced conduction and reduced air leakage, according to the simulation and weather file used, don''t save energy during the cooling season. That is, energy gained by conduction and leakage during sears hot days is balanced by energy removed during cool evenings in the Washington, D.C., climate. Note the implicit assumption that residents keep their windows closed and air conditioners operating even on cool evenings. We didn''t have any quantitative basis for altering this assumption. The window replacement options with low-e glass, on the other hand, show significant projected cooling savings, largely as a result of reduced solar Calculated as energy savings/[ft.sup.2] of window sash area, typical savings for the highest-performance window option are about 0.50 MMBtu/[ft.sup.2] per year in heating and 0.45 MMBtu/[ft.sup.2] per year in cooling. This replacement kit makes replacing old, energy wasting windows, fast and simple. Each kit comes complete with two sash, two vinyl compression balances, one vinyl parting stop, two vinyl sash stops, and all necessary installation hardware. Sash are available primed for painting or aluminum clad in assorted colors. Vinyl casement and awning windows now feature Truth Maxim commercial-grade hardware to make them easier to operate, says the firm. All casement and awning windows come standard with fold-down handles to provide extra room for drape and blind clearance around windows. The firm manufactures numerous other products. 724-465-1800. www.gorell.com, Circle 195. Fusion-welded vinyl windows are perfect for new or remodeling applications because they resist water, corrosion, and mold, claims the firm. Available in white and almond, windows they feature removable nailing fins. Muntins are optional. The company also manufactures aluminum-clad and wood windows as well as patio doors. 800-877-9482. www.summit windows.com. Circle 184. Kolbe & Kolbe Millwork offers vinyl windows. The Wausau, Wis.based, high-end wood window manufacturer will supply a wide selection of vinyl window designs - radius, bow, bay and geometric - through its new KVW Windows & Doors division. The new line includes double hung models, sliders, casements, awnings and sliding doors. A new production plant, located in Manawa, Wis., was scheduled to begin operating in February. ProFinish vinyl windows come in double-hung, single-hung, casement, slider, picture, and geometric-shaped styles. The windows, which won''t pit, peel, or chalk, claims the maker, feature welded frames and sashes and integral J-channels. Numerous glass options and grids are available. 800-542-9118. www.simonton.com. Circle 182. Monument vinyl windows come in white and almond and feature fusion-welded mitered corners and multiple hollow chambers for strength, says the firm. The windows come in casement, awning, double-hung, single-hung, and sliding styles. A number of sears glazing and glass options are available. 800-223-4873, www.hurd.com. Visions 2000 vinyl windows are maintenance-free and won''t rust or corrode, says the firm. The windows are available in single-hung, windows double-hung, casement, and awning styles. The line comes standard with integral nailing fins and fusion-welded corners. Optional grilles and glazes also are available. Cleaning. The existing window system is almost impossible to clean thoroughly from inside the building. As a result, many residents pay for professional cleaning, at a cost of $100 or more, once or twice a year. Tilt-in replacement windows, and elimination of the separate storms, would allow relatively easy cleaning of all surfaces from the interior. Thus, residents who drop professional cleaning in favor of doing it themselves, and consider it a free-time activity, might save sears more in cleaning windows costs than in energy costs.Ventilation. Although the McLean Gardens buildings don''t have mechanical ventilation systems, reports of excess moisture accumulation and mold growth are uncommon. The leaky windows are undoubtedly a major factor in providing natural ventilation rates sufficient to limit moisture accumulation during cold weather. (Air conditioning limits moisture accumulation during the summer.) Window replacement would significantly reduce overall building infiltration. Our sears project did not include measurement of overall building leakage, but we believe that overall natural infiltration rates would be cut by more than windows 50%, and that the resultant increase in interior humidity and condensation would probably cause paint failure and mold growth in some units. This issue could be addressed directly through the installation of mechanical ventilation systems. The risk of excess moisture accumulation and the cost sears and complexity of installing a ventilation system are windows significant factors to be weighed in planning window replacement.
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