in d o o rs
LIVING GREEN
READ THE LABELS
T w o ra tin g system s can h e lp yo u
co m p a re w in d o w s. T h e N a tio n a l
F e n e stra tio n R a tin g C o u n c il (
n frc .o rg
)
e valu ate s p e rfo rm a n ce in these five
categ o ries, lis t in g the re su lts on a lab el
th at co m es w ith the w in d o w :
U -FA C T O R T h is v a lu e , w h ic h
m e a su re s heat tran sfer, ran g es from
.25 to 1.25. T h e lo w e r the nu m b er,
the b etter the w in d o w in su la te s.
(You m a y h e a r the te rm R -v a lu e ,
w h ic h m e a su re s h eat re sista n ce an d
sh o u ld be a h ig h n u m b er. It is m ore
a c c u ra te ly re se rve d for m a te ria ls su c h
as in s u la tio n , ro o fin g , an d sid in g .)
SO LA R H EA T G A IN C O E F F IC IE N T
T h e lo w e r the n u m b e r (ty p ic a lly
.25 to .8), the b etter the w in d o w
b lo c k s h eat g ain .
V IS IB L E T R A N S M IT T A N C E M e a su re d
on a sc a le o f 0 to 1, th is categ o ry
d e scrib e s the a m o u n t o f lig h t the
w in d o w le ts th ro u g h . T h e h ig h e r the
n u m b e r, the better.
A IR LEA K A G E T h e lo w e r the v a lu e
(m e a su re d in c u b ic feet o f a ir p a ssin g
th ro u g h one sq u are foot o f w in d o w
area p e r m in u te ), the better. T h is
n u m b e r sh o u ld be .3 o r less.
C O N D E N S A T IO N R E S IS T A N C E T h is
term re fe rs to a w in d o w ’s a b ilit y to
re sist w ate r b u ild u p ; the h ig h e r the
n u m b e r b etw een 0 an d 10 0 , the better.
A w in d o w that also b ears an
E n e rg y S ta r la b e l h as re ce iv e d h ig h
m a rk s for U -fa c to r an d so la r heat
g a in co e ffic ie n t fro m the D e p a rtm e n t
o f E n e rg y an d the U.S. E n v iro n m e n ta l
P ro te c tio n A g en cy. See w h ic h
w in d o w s are best fo r y o u r c lim a te
zo n e at
en erg ysta r.g o v.
GET EXTRA SAVINGS
T h a n k s to a b ill sig n e d last fa ll,
e n e rg y -e ffic ie n t w in d o w s p u rch a se d
an d in sta lle d in 2 0 0 9 m a y b e e lig ib le
fo r a fed eral tax c re d it (see
e n e rg y sta r
.g o v
for d e ta ils). Y o u m a y also q u a lify
fo r state rebates; see
d sire u sa .o rg .
NOT READY TO REPLACE?
M a k e y o u r e x is tin g w in d o w s m o re
e ffic ie n t b y in s ta llin g in s u la tin g
co v e rin g s, su c h as c e llu la r shades,
c u rta in p a n e ls w ith in te rlin in g s , and
w in d o w film s. In w a rm -w e a th e r
m o n th s, be w illin g to keep y o u r
w in d o w s co vered d u rin g the su n n ie st
tim e s o f the day.
n o MARCH 2009 BETTER HOMES AND GARDENS
