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850 Series Thermacore Door


​​​​​​​​​​​​​​​​Thermacore® AP Door ​Model 850 is engineered to deliver advanced performance in commercial and industrial applications where climate control, durability and ease of maintenance are primary concerns. This sectional steel door system presents the most advanced thermal performance values published by any major US manufacturer of 3" commercial insulated sectional doors. 



R Value: 26

U Value: .038

Thermal Break: 1-3/4" wide PVC thermal break; PVC thermal break on end stiles

Air Infiltration: At 15 mph (24 kmph) .09 cfm/ft² (1.65 m³/hr/m²)


Panel Thickness: 3"

Max Height: 24' 1"

Max Width: 40' 2"

Exterior Steel: .015"

Exterior Surface: Microgrooved, Textured

Standard Springs: 10,000 Cycle

Panel Options

Microgroove, Textured

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Color Options








Window Options

Large Lites (25" x 13")


Insulated Lites (24" x 6")

Door Features

Advanced Thermal Performance


This door system presents the most advanced thermal performance values published by any major US manufacturer of 3" commercial insulated sectional doors with an R-value* of 26, U-value** of .038 and a tested installed U-factor† of .14.


The Thermacore® AP 850 features superior construction with a 3" thick profile consisting of high density foam injected CFC and HCFC-free polyurethane insulation. The polyurethane insulated core offers the best insulation values per square inch.


Delivering further thermal efficiencies, the dual barrier tongue and groove joint profile (patents pending), creates a virtually impenetrable path for air leakage (air infiltration) in between door sections. This exclusive joint profile also serves as a true thermal break, 1-3/4" wide, preventing front and back skins from transferring heat or cold. A second PVC thermal break further prevents heat or cold transfer at the end stiles.

Advanced Perimeter Protection


The advanced perimeter design of the Thermacore® AP 850 door system contributes to the overall superior thermal performance. A uniquely designed curved wall angle provides a tighter fit of the steel jamb seal to the wall angle; minimizing air leakage on the sides of the door system. This system also features top to bottom advanced perimeter protection providing an air infiltration‡ rating at 15 mph of .09 cfm/sq ft (1.65 m³/hr/m²).


The header seal ensures a tight seal at the top of the door. The bottom weatherseal, featuring a rigid PVC retainer and dual durometer PVC bulb seal, locks out air and water leakage through the bottom section. The optional EPDM bulb seal is recommended for extreme weather conditions. Our patent pending enhanced thermal performance jamb seal combines an extended flapper and bulb seal in one unique design to complete the door system’s perimeter protection.


The Thermacore® AP door system furnishes a Sound Transmission Class (STC)†† rating of 22, minimizing noise transfer through and around the door. The higher the STC†† rating the better the buffering is from the transmission of sound through and around the door.

Flexibility in Design


The Thermacore® AP door system sections feature continuous steel strips that run along the width of each section which allows hinges to be placed anywhere along the section, unimpeded lite placement and easier center mounting of a trolley operator. Operation options include chain hoist and electric operator. The varied options of operation and mounting (left or right handed) afford flexibility to meet the needs of the facility and application.

Many Options, Customized Solutions


The Thermacore® AP Model 850 is available with a number of options to meet individual application needs. The large thermal lites afford maximum visibility and light transmittance; available with carefully chosen glazing options that optimize thermal performance including: insulated glass, insulated tempered glass, and multi-wall polycarbonate (clear, white, bronze). Lites come standard with a black frame, color matched frames are also available.


Finish options include two coats of baked-on polyester paint, available in four colors to blend with the design aesthetic of the facility. For applications with advanced security and safety needs consider extra locks, a sensing edge, photo-eyes, and a cable failure device. For high usage projects consider the high cycle springs and high cycle components package. Ask your Overhead Door™ Distributor for more information about the special applications options.​

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