High-R window technology development. Phase 2, Final report
Thls report was p r e p a r e d a s an account of wQrk sponsored by an 3gency o f the U n l t e d S t a t e s G o v e r n m e n t . iWtIwr t h e U n i t e d S t d t e s Government:, nor any agency t h e r e o f , nor any a f t h e i r ernpigyees, makes a n y w a r r a n t y , e x p r e s s or t m p ' l t e d , or assumes any i e g a l liability orresponsibility f o r t h e a c c u r a c y , c o m p l e t e n e s s , or u s e f u l n e s s c# ahy f n f o r m a t i o n , apparatus, o r p r o d u
... tus, o r p r o d u c t , or' p r o c e s s d i s c l o s e d , or r e p r e s e n t s t h a t i t s I J S~ would riot i n f r -i n g e on privately-owned r f g h t s . Reference t h e r e i n t o any s p e c i f i c commercial product, prOCeSj, or' s e r v i c e by tr-adename, t r a d e m a r k , manufacturer., or cstherwi s e , doe$ not f t K e s S a r l l y const'!tiJte orimplq' i t s Endorsement, recommendation, or favoring by t h e U n i t e d S t d t e s Gwernment or any agency t h e r e o f . The v f e w t , a n d cplnfons of' authors e x p r e x e d h e r~: f r " i do nlot n e c e w a r i l y s t a t e o r r -e f l e c t t h m e o f t h e Unf ted S t a t e s Government OT any a g e n c y t h e r e o f . This report is divided i n t o two separate sections. The first section summarizes research activities aimed at developing my>erwindow prototypes for three BPA moriitored (RCDP Cvcle II) homes. The second ~A o r i summarizes the results of the monitoring effort &ring the 1989-1900 heating season o n these three homes. ABSTRACT Of all building envelope elements, windows always have had the highest heat loss rates. However, recent advances in window technologies such as low-emissivity (low-E) coatings and low-conductivity gas fillings have begun to change the status of windows in the building energy equation, raising the average R-value (resistarm to heat flow) from 2 to 4 h-Et2-'F,Ehu. Building on this trend and using a novel combination of low-E coatings, gas-fills, and three glazing layers, the authors developed a design concept for R-6 to R-10 "super" windows. Three major window manufacturers produced prototype superwindows based on this design for testing and dernonstration in thee utiMy-spon.wred and -monitored energy-consening homes in northwestern Montana. This paper disciisses the design and tested penPormance of these three windows and identifies areas requiring further research if these window concepts are to be successfully developed for mass markets.