%0 Conference Paper %B ACEEE 1996 Summer Study on Energy Efficiency in Buildings: Profiting from Energy Efficiency %D 1996 %T The National Energy Requirements of Residential Windows in the U.S.: Today and Tomorrow %A Karl J. Frost %A Joseph H. Eto %A Dariush K. Arasteh %A Mehry Yazdanian %X

This paper describes an end-use analysis of the national energy requirements of U.S. residential window technologies. We estimate that the current U.S. stock of 19 billion square feet of residential windows is responsible for 1.7 quadrillion BTUs (or quads) per year of energy use - 1.3 quads of heating and 0.4 quads of cooling energy - which represents about 2% of total U.S. energy consumption. We show that national energy use due to windows could be reduced by 25% by the year 2010 through accelerated adoption of currently available, advanced window technologies such as low-e and solar control low-e coatings, vinyl and wood frames, and superwindows. We evaluate the economics of the technologies regionally, considering both climatic and energy price variations, and find that the technologies would be cost effective for most consumers.

%B ACEEE 1996 Summer Study on Energy Efficiency in Buildings: Profiting from Energy Efficiency %C Pacific Grove, CA %8 08/1996 %G eng %U http://aceee.org/files/proceedings/1996/data/papers/SS96_Panel10_Paper07.pdf#page=1 %L LBNL-39692 %1

Windows and Daylighting Group

%2 LBNL-39692 %0 Report %D 1993 %T Savings from Energy Efficient Windows: Current and Future Savings from New Fenestration Technologies in the Residential Market %A Karl J. Frost %A Dariush K. Arasteh %A Joseph H. Eto %X

Heating and cooling energy lost through windows in the residential sector (estimated at two-thirds of the energy lost through windows in all sectors) currently accounts for 3 percent (or 2.8 quads) of total US energy use, costing over $26 billion annually in energy bills. Installation of energy-efficient windows is acting to reduce the amount of energy lost per unit window area. Installation of more energy efficient windows since 1970 has resulted in an annual savings of approximately 0.6 quads. If all windows utilized existing cost effective energy conserving technologies, then residential window energy losses would amount to less than 0.8 quads, directly saving $18 billion per year in avoided energy costs. The nationwide installation of windows that are now being developed could actually turn this energy loss into a net energy gain. Considering only natural replacement of windows and new construction, appropriate fenestration policies could help realize this potential by reducing annual residential window energy losses to 2.2 quads by the year 2012, despite a growing housing stock.

%G eng %L LBNL-33956 %1

Windows and Daylighting Group

%2 LBL-33956 %0 Report %D 1993 %T Window U-Value Effects on Residential Cooling Load %A Robert Sullivan %A Karl J. Frost %A Dariush K. Arasteh %A Stephen E. Selkowitz %X

This paper presents the results of a study investigating the effects of window U-value changes on residential cooling loads. We used the DOE-2.1D energy analysis simulation program to analyze the hourly, daily, monthly, and annual cooling loads as a function of window U-value. The performance of a prototypical single-story house was examined in three locations: hot and humid, Miami FL; hot and dry, Phoenix AZ; and a heating-dominated location with a mildly hot and humid summer, Madison WI. Our results show that when comparing windows with identical orientation, size, and shading coefficient, higher U-value windows often yield lower annual cooling loads, but lower U-value windows yield lower peak cooling loads. This occurs because the window with the higher U-value conducts more heat from inside the residence to the outside during morning and evening hours when the outside air temperature is often lower than the inside air temperature; and, a lower U-value window conducts less heat from outside to inside during summer afternoon peak cooling hours. The absolute effects are relatively small when compared to total annual cooling which is typically dominated by window solar heat gain effects, latent loads, and internal loads. The U-value effect on cooling is also small when compared to both the effects of U-value and solar heat gain on heating load. Our modeling assumed that U-value and solar heat gain could be independently controlled. In fact, reducing window conductance to the levels used in this study implies adding a second glazing layer which always reduces solar heat gain, thus reducing annual cooling. Thus, when we compare realistic options, e.g., single pane clear to double pane clear, or single pane tinted to double pane tinted, the double pane unit shows lower annual cooling, as well as lower peak loads.

%G eng %L LBL-34648 %1

Windows and Daylighting Group

%2 LBL-34648