Choosing between interior and exterior doors might seem simple until you realize how much it impacts your home’s safety, comfort, and efficiency.
According to HomeAdvisor, exterior doors can cost 2–4 times more than interior ones due to their insulation and security requirements. That’s why understanding the key differences is vital before you buy.
At Seanote Construction, we don’t just help you choose a door, we help you make decisions that last. With a reputation for tackling tough jobs and doing what’s right, we bring clarity, precision, and long-term value to every project.
Key Takeaways:
- Interior and exterior doors are made from different materials tailored to their function, with interior doors focusing on aesthetics and cost, and exterior doors on durability and security.
- Exterior doors are significantly more expensive, thicker, and require more maintenance than interior doors due to insulation and weather resistance needs.
- Using an interior door in an exterior setting compromises safety, energy efficiency, and structural integrity, and is strongly discouraged.
What Are Interior Doors Made Of?
Interior doors are primarily made from hollow core, solid core, MDF, and wood, each offering unique advantages suited to different situations.
Hollow Core Doors
These doors are lightweight and affordable, making them ideal for interior spaces like bedrooms, closets, and bathrooms. They have a honeycomb cardboard core covered by a thin layer of wood or composite material.
According to the Woodwork Association, most interior residential doors are hollow-core or MDF due to their cost-effectiveness and versatility.
Pros
- Affordable
- Lightweight and easy to install
Cons
- Poor sound insulation
- Low durability
Solid Core Doors
Solid core doors offer improved durability and sound insulation, often made from compressed wood fibers. They are commonly used in rooms requiring better soundproofing, like home offices or bedrooms.
Pros
- Good sound insulation
- Durable and sturdy
Cons
- Heavier, requiring stronger hinges
- More expensive than hollow core
MDF Doors (Medium Density Fiberboard)
MDF doors are engineered from wood fibers, glue, and resin, resulting in a smooth, paint-friendly surface. They’re popular for interior doors due to their affordability, versatility in design, and ease of finishing.
Pros
- Smooth, consistent finish
- Affordable and customizable
Cons
- Susceptible to water damage
- Heavier than hollow core
Wood Doors
Solid wood doors provide excellent aesthetics, durability, and natural insulation. They’re favored for high-end interiors where appearance and long-term value matter.
Pros
- Visually appealing, natural finish
- Excellent durability
Cons
- Expensive
- Susceptible to warping in humid conditions
What Are Exterior Doors Made Of?
Exterior doors are typically crafted from durable materials such as fiberglass, steel, wood, and aluminum, chosen for their ability to withstand weather, offer security, and provide insulation.
Fiberglass Doors
Fiberglass doors are popular due to their durability, energy efficiency, and versatility. They can mimic the look of real wood while being resistant to moisture, dents, and rust.
According to the U.S. Department of Energy, fiberglass doors typically have a lifespan of 20–30 years, significantly longer than wooden doors, especially in humid climates.
Pros
- Excellent insulation and energy efficiency
- Low maintenance, weather-resistant
Cons
- Slightly higher initial cost than steel
Steel Doors
Steel doors are widely chosen for their strength and security features. They’re also highly energy-efficient due to their insulated core, offering excellent protection against extreme weather conditions.
Pros
- Exceptional security and durability
- Cost-effective and energy-efficient
Cons
- Vulnerable to rust and dents
Wood Doors
Wood exterior doors offer natural beauty and timeless elegance, favored in traditional homes. However, wood requires regular maintenance to prevent warping and weather damage.
Pros
- Beautiful, high-end appearance
- Good natural insulation
Cons
- Requires regular maintenance (painting, staining)
- Shorter lifespan in humid climates (typically 10–15 years)
Aluminum Doors
Aluminum doors are lightweight, corrosion-resistant, and highly durable. They’re frequently used in modern home designs and commercial buildings.
Pros
- Durable and resistant to corrosion
- Low maintenance, suitable for humid climates
Cons
- Limited insulation capabilities without thermal breaks
What Are the Standard Sizes for Interior and Exterior Doors?
Door sizes are standardized to allow for compatibility, ease of installation, and functionality. Knowing the typical sizes helps when choosing doors that fit both structurally and aesthetically within your home.
Interior Door Sizes
Interior doors commonly measure:
- Height: 80 inches (6 feet, 8 inches)
- Widths: Typically range from 24 to 36 inches, with 30 inches being the most common for bedrooms and 24 inches for closets.
- Thickness: Usually 1 3/8 inches thick.
Interior doors’ thinner construction contributes to their lower weight, affordability, and easier installation.
Exterior Door Sizes
Exterior doors generally have slightly different sizing standards:
- Height: Typically 80 inches, with taller options like 84 inches (7 feet) or 96 inches (8 feet) for grander entrances.
- Widths: Common widths are 32, 34, or 36 inches, with 36 inches being standard for primary entry doors.
- Thickness: Typically 1 3/4 inches thick, providing additional insulation, security, and durability.
Size Comparison Table
| Door Type | Standard Height | Common Widths | Standard Thickness |
| Interior | 80 inches | 24″-36″ | 1 3/8 inches |
| Exterior | 80-96 inches | 32″-36″ | 1 3/4 inches |
How Do Costs Compare Between Interior and Exterior Doors?
Exterior doors generally cost significantly more than interior doors due to differences in materials, construction quality, insulation, and security features.
Interior Doors Costs
Interior doors are more budget-friendly, with price variations based on material and design.
- Hollow Core: Typically $30–$100 per door.
- Solid Core: Around $100–$250 per door.
- MDF: Usually $50–$200 per door.
- Wood (solid): Ranges from $200–$600+ per door.
Additional Costs: Installation typically adds $50–$150 per door.
Exterior Doors Costs
Due to higher durability requirements, exterior door pricing varies considerably:
- Steel: $150–$500, offering a good balance of security and affordability.
- Fiberglass: $250–$1,500, popular for durability and insulation.
- Wood: Typically $500–$3,000+, favored for aesthetic appeal but requiring maintenance.
- Aluminum: Usually around $500–$2,000.
Additional Costs: Installation often costs between $250–$600, reflecting complexity and higher standards required for security and weatherproofing.
Maintenance and Longevity: What Is the Difference Between Exterior and Interior Doors?
Maintenance requirements and lifespan significantly vary between interior and exterior doors due to exposure, materials, and daily wear.
Interior Doors
Interior doors experience minimal weather exposure, leading to longer intervals between maintenance tasks.
Maintenance Recommendations
- Regular cleaning to remove dust and dirt.
- Periodic repainting or refinishing, approximately every 5–10 years.
- Tightening hinges and hardware annually.
Exterior Doors
Exterior doors are exposed to harsh environmental conditions, requiring more frequent and intensive maintenance.
Maintenance Recommendations
- Inspect and reseal weather stripping annually.
- Regular painting or staining every 2–5 years for wooden doors.
- Checking for rust or corrosion annually on steel doors.
- Cleaning fiberglass and aluminum doors at least twice a year.
Choosing doors with maintenance requirements aligned to your capabilities helps confirm the longevity and aesthetics of your home, optimizing your investment.
Can an Interior Door Be Used as an Exterior Door?
While it may seem convenient or cost-effective, using an interior door as an exterior door is typically not advisable due to significant differences in construction, insulation, and security.
Common Misconceptions
- Misconception: Interior doors can simply be sealed or painted for outdoor use.
- Reality: Interior doors lack the structural integrity and weather resistance essential for exterior environments.
Using an interior door externally can lead to:
- Reduced Thermal Efficiency: Reduced Thermal Efficiency: According to the Building Performance Institute, using an interior door in place of an exterior one can result in a 40–60% loss in thermal insulation efficiency compared to properly rated exterior doors.
- Security Risks: Interior doors generally do not provide adequate strength or reinforcement needed to prevent forced entry or withstand harsh weather.
Potential Risks
- Accelerated deterioration from weather exposure (moisture, sunlight, and temperature extremes).
- Increased vulnerability to break-ins due to weaker construction.
- Higher energy costs due to poor insulation properties.
Which Door Type is Best for Your Home?
Choosing between interior and exterior doors comes down to several key factors: location, climate, security, aesthetics, and budget. To simplify your decision, consider the following criteria:
Decision Framework:
- Climate & Weather Exposure:
- Exterior doors must withstand rain, snow, wind, and sun. Fiberglass or steel doors provide superior protection.
- Interior doors are suitable only for dry, climate-controlled environments.
- Security Requirements:
- Exterior doors should offer robust construction, reinforced locks, and security features.
- Interior doors typically don’t require strong security measures.
- Budget & Costs:
- Interior doors are more affordable and require lower installation and maintenance costs.
- Exterior doors, though costlier, provide essential long-term benefits such as better insulation and security.
- Maintenance & Longevity:
- Exterior doors demand higher maintenance but offer longer lifespans (20–30 years).
- Interior doors are low-maintenance, suitable for low-traffic interior spaces.
- Aesthetic Preferences:
- Interior doors focus on complementing indoor décor and providing privacy.
- Exterior doors are a home’s visual statement, combining functionality with curb appeal.
Built to Last, Backed by Seanote
At Seanote Construction, we treat every decision like it matters, because it does. From custom homes to bathroom remodels and everything in between, we guide you through each choice with integrity, professionalism, and honest answers.
Let’s talk about your next project. Contact us now and discover what it means to work with a contractor who always has your back.