Can hollow metal doors be insulated?

Yes, hollow metal doors can be insulated, and there are several types of insulation that can be used for this purpose. Here are some of the most common types of insulation used for hollow metal doors:

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1. Honeycomb insulation is made of a core material that is shaped like a honeycomb. This core material can be made of different materials such as paper, aluminum, or plastic. The honeycomb core is sandwiched between two layers of metal to create an insulated metal door. Honeycomb insulation provides good thermal insulation and is lightweight, making it a good choice for doors that need to be lightweight and easy to operate.

Honeycomb cores get their name from the honeycomb shaped cardboard that is hardened by special resins. This material is the most commonly used at interior openings and is a heavy-duty, durable core. It can be fire rated up to 3 hours. The insulation value is lower than a foam core but it can be used at exterior openings if a cost effective solution is desired.
[L18 Series, per ASTM C1363] R-Factor = 1.80 / U-Factor = .56

2.Polystyrene insulation, on the other hand, is made of expanded polystyrene foam (EPS). This type of insulation is commonly used for insulating walls, roofs, and floors, but it can also be used for insulating hollow metal doors. Polystyrene insulation is lightweight, easy to install, and provides good thermal insulation. It can also help reduce noise transmission through the door.

Both honeycomb insulation and polystyrene insulation can be effective at insulating hollow metal doors. The choice of insulation will depend on the specific needs of the door and the building it is installed in. For example, if the door needs to be lightweight and easy to operate, honeycomb insulation may be a better choice. If thermal insulation and noise reduction are the primary concerns, polystyrene insulation may be a better choice. It is recommended to consult with a professional to determine the best type of insulation for your specific needs.

3. Polyurethane Foam Insulation: This type of insulation is commonly used for metal doors as it provides excellent thermal insulation and sound dampening. Polyurethane foam insulation is injected into the hollow core of the door and expands to fill the cavity. Once cured, it provides an airtight seal, which prevents drafts and reduces noise transmission.Mineral Wool Insulation: This insulation material is made of rock or slag wool and is highly effective at absorbing sound. It is often used in buildings where noise control is a concern.


44 mm thick steel doors shall conform to the specification of
ANSI A250.8-2003/HMMA 861-06/SDI 100.
“PU” doors are made full-flush or seamless type (optional). Face sheets are commercial quality cold rolled steel conforming to ASTM A1008/A 1008M-02, A653/A 653M-01 Galvanized or A666-00 Stainless Steel
Doors are mechanically interlocked, hemmed, and vertical edges have no visible seams on faces. Face sheets are totally supported by a foamed-in-place polyurethane core. The core fills the entire door cavity and is chemically bonded to all interior surface. Density of foam exceeds 36kg/cm3. The top and bottom door edges are closed inverted by 1.5 mm steel channels welded in place.


1.0 mm / 1.25 mm / 1.5 mm / 2.0 mm

Fire Ratings

Conforming to ANSI/NFPA 80-1999 Up to 180 mins

4. Mineral wool insulation is typically placed inside the hollow core of the door, and it can also help improve the door’s fire resistance.Fiberglass Insulation: This insulation material is made of glass fibers and is commonly used in homes and commercial buildings.

5. Steel Stiffened

Steel stiffened hollow metal doors have steel channels that run the full height of the door and are spaced about 6″ O.C. across the width of the door. They are spot welded to the faces and the gaps between the channels is filled with insulation. These doors are often specified at high abuse areas or can be used at openings where sound transmission ratings are a concern.
[B18 Series, per ASTM C1363] R-Factor = 2.01 / U-Factor = .50