Operating with a single handle, these custom windows open inwardly like a hopper window and open wide in the traditional in-swing style. The concealed hardware offers secure locking and ease of use.

Photo © Canan Akyüz

Wood Species
& Finishes

Duratherm sources all its materials by project, only from providers we know and trust. Many of our woods come from Forest Stewardship Council® (FSC- C108949) certified sources. We obtain others from sustainably-harvested plantations. Fourteen domestic and exotic wood species offer a wide range of colors, grains, and textures.

Please contact us for information about finishing options (including paint, Sikkens, clear laquer, stain, bleach stain, oil, etc.) and to discuss the use of a species not on our standard menu. We consider availability, durability, machining, and gluing characteristics to determine the feasibility of your choices.



KEY (mouse over #s to view details)

Detail: Head




Multi-latchpoint fully-concealed locking hardware controlled by single lever handle control. Horizontal and vertical perimeter locking points ensure weather-tight performance and security. In the turn mode, an adjustable friction stay holds window in any open position from 0° to 90°. In the tilt mode, the sash projects in at head approximately 10° to provide controlled ventilation without compromising security. Egress: Available as quick-release pin at sash connection.

Lever Handle

Operating hardware accepts any lever handle with 43mm attachment spacing and 7mm sq. spindle. A wide variety of styles and finishes are available from various manufacturers.

Optional Hardware

Custodial locks, sash restrictors, removable operating handle.

Insect Screens

1" x 1/4" tubular extruded frames in anodized bronze, mill finish aluminum or custom color painted aluminum. Mesh of 18 x 16 screen cloth held with vinyl spline, available in charcoal finished aluminum, mill finish aluminum, stainless steel or bright brass. Maximum width of screen mesh is 72". Wood-framed screens are available.


All glazing is per project specifications. Duratherm can accommodate most configurations and make-ups from 1/8" single glazed to a maximum of 1 3/4" security glass.
Clear glass opening: Unit height minus 7 3/4", unit width minus 6 3/4".


Double continuous extruded silicone flap gasket set in rebate around the perimeter of the sash. Engaging the multilatchpoint espagnolettes compresses the weather-strip to ensure a tight seal.


The minimums and maximums shown are intended as guidelines. For applications that exceed these ranges, please contact the factory for assistance.


Minimum: 18”
Maximum: 62"


Minimum: 30”
Maximum: 96"

To ensure smooth and troublefree operation over time:
At maximum width of: 62", limit height to: 60"
At maximum height of: 96", limit width to: 36"
Maximum area for a single sash: 25 sq ft


Based on:
20" clear width
24" clear height
5.7 sq ft clear opening
Minimum unit width: 28"
Minimum unit height: 30"

To meet egress requirements:
At minimum unit width of: 28", height must be at least: 48"
At minimum unit height of: 30", width must be at least: 40"

Frame Depths

Standard: 6 1/4”
Minimum*: 4 3/4”
Maximum: 10”

(*Contact factory for frame depths less than 6¼")




Static Air Infiltration:
ASTM E283 cfm/ft2 @ 1.57 psf

Allowed 0.10
Test Result 0.005

Water Infiltration:
ASTM E547-cyclic ASTM E331-static at 8 psf

Allowed 0.0
Test Result 0.0

Load Deflection:
ASTM E330 10 sec at +60 and -60 psf


Sash Torsion:
AAMA/WDMA/CSA 101 / I.S.2 / A440


Vertical Deflection:
AAMA/WDMA/CSA 101 / I.S.2 / A440


Forced Entry:


Thermal Transmission


Center of Glass:
ASTM C-236 U-value using Viracon VE1-2M Low E glass and Lawrence Berkeley Laboratories Winow 5.2 analysis program.

1": 0.29
with Argon: 0.24

Total Unit:

1": 0.34
with Argon: 0.30

Hurricane Impact


Large Missile Impact and Cyclical Air Pressure:
- ASTM E1996-05, ASTM E1886-05
- Tested at 42 psf
- Wind Zone 3, not including Dade County, FL
- Missile Level D

Note: Contact factory for size limitations
and detail modification required for
hurricane certified units.