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To replacement do this, we selected CONTAM, a program developed by the National Institute for Standards and Technology and available flee through its Web site (see information at the end of this article). CONTAM calculates instantaneous values of air flow through openings in buildings, using the flow characteristics of each opening, orientation, height, and other factors, based on a weather file that provides temperature and wind information. We set up our CONTAM runs to calculate air flow for each hour of the typical windows year, and then summarized the results by month.To complete the energy simulation inputs, we gathered information on building envelope construction and estimated appliance loads, hot water usage, and occupancy for each unit type. Water-to-air heat pumps installed in each unit provide heating and cooling at McLean Gardens. Six central plants equipped with boilers and cooling towers provide prices and replacement conditioned water at roughly 70[degrees]F to the heat pumps as a source or sink for energy. We took advantage of Visual DOE''s ability to model this system by grouping an upper, middle, and lower unit together windows with a central plant for each analysis. Comfort. Window replacement at McLean Gardens prices would result in reduced window air leakage and increased wintertime temperatures at the inner glass surface. Reduced air leakage means fewer drafts near windows. Increased wintertime glass temperature would reduce cold convection currents that spill off windows, further reducing replacement the sensation of drafts. The temperature increase would also increase the average radiant temperature of the indoor windows environment. (Average radiant temperature has nearly as strong an influence on comfort as does air temperature.) While all the replacement options would yield prices some increase in temperature, the higher-performance low-e, argon-filled glass would offer the greatest increase. While improved comfort has value in itself, it may also result in thermostat adjustments that yield additional replacement real energy savings. The cooling results brought another surprise in projecting only tiny windows energy savings for prices the storm windows or non-low-e replacement windows. This occurs because reduced conduction replacement and reduced air leakage, according windows to the simulation and weather prices file used, don''t save energy during the cooling season. That is, energy gained by conduction and leakage during hot days is balanced by energy removed during cool replacement evenings in windows the Washington, D.C., climate. Note the implicit assumption that residents keep their windows closed and air conditioners operating prices even on cool evenings. We didn''t have any quantitative basis for altering this assumption. The window replacement replacement options with low-e glass, on the other hand, show significant projected cooling savings, largely as a result of reduced solar windows Calculated as energy savings/[ft.sup.2] of window sash area, typical savings for the highest-performance prices 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.
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