What Is the Difference Between an Interior and Exterior Door?

Post by manhattandoor on June 15th, 2020

Updated December 21st, 2023

What differentiates an interior door from an exterior door? It is more than just the location in a building. There are many differences between interior and exterior doors that even contractors can overlook. Since one provides a barrier between interior spaces and the other between interior and exterior environments, the physical properties of these different door types must serve unique purposes.

A door is an important mechanism designed for specific uses in certain situations. That is why choosing the proper door types for your buildings requires help from our team who knows doors. We at Manhattan Door understand what constitutes interior vs. exterior doors, and can help you make the correct choices for your applications.

Interior vs. Exterior Door Appearance

Interior and exterior doors typically differ in appearance. The visual characteristics of each type of door include:

Interior Doors

• Used as entrances and exits between rooms inside your building
• Typically lighter and thinner than exterior doors
• Generally cost less than exterior doors
• Can include wooden, metal, glass or a combination of these features
• Typically come in a single-door construction
• Can feature decorative panels on both sides of the door

Exterior Doors

• Function as the main entrance and exit to your building
• Provide insulation and a temperature barrier between your building and the outside
• Require special treatment to prevent weathering and related damage
• Treated to withstand high moisture levels
• Often come in double door constructions
• Usually have more security features than interior doors
• Can feature decorative panels on the outside

Material

Interior and exterior doors share many of the same materials, yet there are typically a few key differences between each.

Interior Doors

• Normally feature a hollow core
• Can be made from glass, metal, wood, fiber wood or a combination of these materials
• Mostly offered in single-material construction varieties
• Usually made with limited resources, hence a shorter construction process

Exterior Doors

• Made to withstand the elements and protect your building’s interior from inclement weather
• Feature tougher, more moisture-resistant adhesive
• Normally feature a solid core
• Can be made from a combination of glass, metal, steel and wood
• Usually comes with a reinforced metal door frame
• May need multiple construction layers to provide enough insulation and protection from the elements

While interior doors are usually made from only one material, exterior doors need multiple construction layers to provide enough insulation and protection from the elements.

Thickness Differences: Interior & Exterior Doors

Exterior doors are constructed to be much thicker than interior doors due to their function. While interior doors are subjected to far less wear and tear, exterior doors require an extra thick core, usually wooden, to keep out the heat and cold. Exterior doors almost always include a thick layer of veneer for insulation and protection against weather damage. While interior doors are made for frequent, easy use, exterior doors provide a protective barrier for the building.

Core Construction

To properly function as barriers between the inside and outside, exterior doors have a solid core construction. Exterior doors usually consist of wood or woodgrain cores surrounded by layers of steel or metal for maximum temperature control and security features.

Interior doors are designed to be lighter and thinner than exterior doors and often feature a hollow core. However, more expensive interior doors include a type of wood fiber core or a honeycomb-like interior to help muffle sounds. Honeycombed core doors offer greater resistance to sound. Plus, its structural properties provide thermal insulation that makes it a better option than typical hollow core doors.

Insulation Differences: Exterior and Interior Doors

In addition to providing a secure barrier between a building’s interior and the outdoors, exterior doors are constructed with optimal insulation capabilities. Their multilayered construction typically features some form of insulation. Steel doors, for instance, will usually have foam cores to regulate temperature.

Interior doors can also have insulation, although this is not common. As mentioned, honeycombed doors are excellent interior doors that offer some thermal insulation.  However, interior doors with solid core construction can provide moderate draft protection.

Sizing Requirements

Because exterior doors serve as the main entrance and exit points in a building, they are almost always larger and heavier than interior doors. Due to their extra thickness, exterior doors are designed with protection from the elements in mind rather than usability. Today, many exterior doors also include ADA-compliant features, such as  guidelines for clear width and vertical clearances. According to ADA accessibility standards, the door should be at least 32 inches wide and 80 inches tall.

Conversely, interior doors do not need to be as thick or heavy as their exterior door counterparts and are normally uniform in construction. If you are wondering whether you can use an interior door as an entry door that comes in contact with the exterior or vice versa — the answer is almost always no. Each door type is designed for unique purposes. Plus, using an interior door on your building’s exterior will result in rapid wear and tear — and an outrageous heating bill.

Unique Characteristics of Exterior and Interior Doors

Automation is another important element. Due to the heavy construction of the exterior doors, many come with automatic opening buttons. The automatic feature is functional, especially if the door requires force to open. The American National Standards Institute (ANSI), together with the Builders Hardware Manufacturers Association (BHMA), sets certain guidelines for door features, including opening speed and automation level.

In comparison, interior doors may not need to fully comply with the automation requirements. Instead, their unique characteristics lie in aesthetics. Interior doors lean toward design rather than function, offering a variety of styles. You can tailor the door according to the home’s overall design and architecture.

Specific Components

Because of the differences in sizing dimensions, the components necessary for installing exterior and interior doors also vary. To better understand the differences between them, let us take a closer look at the door materials required for installation.

Interior vs. Exterior Door Jambs

Exterior door jambs are generally bigger and sturdier because of the increased weight and larger physical dimensions of exterior doors. They need to be durable to regulate temperature properly. Interior door jambs do not necessarily have requirements to follow as long as they can handle the door’s weight.

Interior vs. Exterior Door Handles

Interior door handles generally prioritize privacy and aesthetics, while durability and security are the main focuses for exterior door handles. Heavier construction may also impact the need for automation.

Interior vs. Exterior Door Hinges

Door hinges for exterior doors are usually made of metals, specifically stainless steel, to conform with the structural dimensions. This material also adapts to and withstands weather conditions and environmental challenges. Meanwhile, interior door hinges often use iron and copper.

Choosing Your Interior Door

If you are a contractor or building project manager looking for the perfect interior doors for your construction project, browse our collection of customizable, high-quality interior doors. Choose from an array of durable, beautiful materials that meet your design and construction needs — we are always here to help.

Contact us today if you have any more questions about the differences between interior and exterior doors.