U-FACTOR
Minimizes unwanted heat
flow through our door for
better thermal performance.
WHAT YOU NEED TO KNOW

Heat flows from warmer to cooler
bodies. Doors lose heat to the
outside in

the Winter and gain heat from the
outside during the Summer

STANLEY can reduce the U-factor
by up to 40%* by better preventing
interior heat from escaping to the
outside

Depends on size, temperature and
components of the door
1” GLASS
U-FACTOR
REFERENCE NUMBERS

Colder climates want a low UFactor (.52) to resist heat loss

Based on IECC C402.4.3

ASHARE 90.1

NFRC 100: 1.10 - .77 BTU (hr) (F
temp differential)*

Dura-Glide GreenStar Range
1.04-.52
*Compared to ¼” glass, insulated glass on a typical 14’ Dura-Glide GreenStar bi-parting door
U-FACTOR GUIDE | Cooler climates can prevent heat loss
HIGH U-FACTOR
LOW U-FACTOR
don’t need to resist heat loss
resists heat loss
U-Factor Glass with Door Frame
1.20
1
1.00
U-FACTOR 0.52
Recommend:
Bi-parting 192” x 92” or Single Slide
108” x 92” with transom. 1” SB60
argon glass, 4” bottom rails, no
muntins, narrow stiles
3
0.80
2
2
Recommend:
Bi-parting 168” x 92” or Single Slide
96” x 92” with transom, 1” glass with
SB60 air glass, 10” bottom rails, 2”
muntins, narrow stiles
0.60
1
0.40
3
0.20
0
COLD
CLIMATE
U-FACTOR 0.62
HOT
U-FACTOR 1.03 - 1.04
Recommend:
Bi-parting 168” x 92” or Single Slide
96” x 92”, 1/4” glass, no transom,
10” bottom rails, 2” muntins, narrow
stiles
Simulations performed by an NFRC accredited lab
U-FACTOR GUIDE | Maximize glass for best results
Bi-parting, 192” X 92“
Single Slide 108” X 92“
4" Bottom Rails, No Muntins, Narrow Stiles, No Transom
Bi-parting, 168” X 92“
Single Slide, 96” X 92”
10” Bottom Rails, 2” Muntin, Narrow Stiles, No Transom
1.20
1.03 - 1.04 1.04
U-Factor Glass with Door Frame
1.02 1.04
1.00
IECC Range
0.80
Dura-Glide
with ¼” Glass
IECC Range
Dura-Glide
with ¼” Glass
0.77
0.77
0.64
0.60
0.56
0.40
0.53
0.62
Dura-Glide
GreenStar
Dura-Glide
GreenStar
0.20
0
¼” Glass
SB60 Air
SB60 Argon
(1.03)
(0.29)
(0.24)
GLASS TYPE
¼” Glass
SB60 Air
SB60 Argon
(1.03)
(0.29)
(0.24)
Simulations performed by an NFRC accredited lab