How To Insulate Exterior Door
Exterior Door

How To Insulate Exterior Door


How To Insulate Exterior Door: Whether you’re seeking to combat drafts, reduce energy bills, or simply improve the insulation of your home, this step-by-step tutorial is your go-to resource. An exterior door is a critical point of contact between your home and the external elements. Proper insulation ensures that your indoor climate remains stable, preventing cold drafts from entering during winter and keeping cool air in during the sweltering heat of summer. Beyond temperature regulation, effective insulation also provides noise reduction and heightened privacy.

In this guide, we break down the insulation process into easily manageable steps, accompanied by detailed explanations and visual aids. From selecting the appropriate insulation materials to preparing the door and framing, each phase of the process is demystified. Furthermore, we’ll delve into various insulation techniques, such as weatherstripping and sealing gaps, to ensure a comprehensive approach to insulation.

Whether you’re a seasoned DIY enthusiast or a newcomer to home improvement projects, this guide caters to all skill levels. The benefits of a well-insulated exterior door extend far beyond the immediate comfort of your living space—it’s an investment in energy savings and environmental sustainability.

By the end of this guide, you’ll possess the knowledge and confidence to successfully insulate your exterior door, thereby contributing to a more energy-efficient and comfortable home. Let’s dive into the world of exterior door insulation and take the first step toward a cozier, more economical living environment.

How To Insulate Exterior Door

What is the best insulation around the exterior door?

Weatherstripping is the most common insulation around any door. While it comes in many styles, you’ll want to remove old weather stripping and wash the doorjamb before installing new foam.

Choosing the best insulation around an exterior door depends on various factors, including climate, budget, and personal preferences. There are several common insulation materials used around exterior doors:

a. Weatherstripping: Weatherstripping is a cost-effective and easy-to-install option. It involves sealing gaps around the door frame and threshold. Weatherstripping materials include adhesive-backed foam tape, door sweeps, and silicone caulk. These materials prevent drafts and moisture from entering, improving energy efficiency and comfort.

b. Fiberglass Insulation: Fiberglass insulation is a popular choice for insulating around exterior doors. It comes in batts or rolls and can be placed in the wall cavity around the door frame. It’s relatively easy to install and offers good thermal insulation properties.

c. Spray Foam Insulation: Spray foam insulation is an excellent option for creating an airtight seal around exterior doors. It expands to fill gaps and crevices, providing superior insulation and preventing air infiltration. However, professional installation is recommended due to its chemical nature.

d. Rigid Foam Insulation: Rigid foam boards, such as expanded polystyrene (EPS) or extruded polystyrene (XPS), are effective insulators for exterior doors. They can be cut to fit around the door frame, offering both thermal insulation and moisture resistance.

e. Door Insulation Kits: These kits typically include foam panels that adhere to the interior side of the door. While they’re not as effective as other methods for insulating the entire door area, they can be a quick and affordable solution for improving insulation.

Ultimately, the best insulation for your exterior door will depend on your specific needs, budget, and the level of insulation required in your region’s climate.

Do exterior doors need to be insulated?

The front door of your home is the main access to your home. It is also an opening for cold air, water infiltration, and insects. Your exterior doors must be well insulated to protect your home from the outside elements.

Yes, exterior doors should be insulated. Insulation around exterior doors is crucial for several reasons:

a. Energy Efficiency: Insulating exterior doors helps to prevent heat transfer. In the winter, it keeps warmth inside your home, reducing heating costs. In the summer, it prevents hot outdoor air from entering, reducing cooling costs. This contributes to overall energy efficiency.

b. Comfort: Proper insulation ensures that your home remains comfortable year-round by maintaining consistent indoor temperatures and reducing drafts.

c. Moisture Control: Insulation helps to control moisture infiltration, preventing condensation and potential damage to the door and surrounding structure.

d. Noise Reduction: Insulation also helps reduce outside noise from entering your home, enhancing your living environment.

e. Longevity: Insulation can prolong the life of your exterior door by protecting it from extreme temperature fluctuations and moisture-related issues.

In summary, insulating exterior doors is a fundamental aspect of home construction and renovation to improve energy efficiency, comfort, and overall durability.

What insulation is used in exterior doors?

Fiberglass exterior doors are made from two large molded sides that are filled in the center with a polyurethane foam core that insulates the door against extreme temperatures. This manufacturing process makes fiberglass one of the most durable and energy-efficient options on the market.

Exterior doors typically come pre-insulated, but the type of insulation used can vary depending on the door’s design and manufacturer. Common insulation materials for exterior doors include:

a. Polyurethane Foam: Many modern exterior doors are insulated with polyurethane foam. This foam offers excellent thermal insulation properties and helps create a more energy-efficient door.

b. Polystyrene Foam: Some doors use polystyrene foam insulation, which provides good thermal performance and is relatively lightweight.

c. Honeycomb Core: Steel and fiberglass exterior doors often feature a honeycomb core structure. While this doesn’t use traditional insulation materials, it provides some insulating properties and enhances the door’s strength.

d. Wooden Core: Solid wood doors naturally have insulating properties due to the wood’s density. However, these doors may still benefit from additional weatherstripping or a door sweep to improve insulation.

It’s essential to consider the door’s U-factor and R-value when evaluating its insulation properties. A lower U-factor indicates better thermal insulation, while a higher R-value suggests superior resistance to heat flow. When selecting an exterior door, look for one with appropriate insulation materials that meet your energy efficiency and climate needs.

What is the best way to insulate exterior walls?

Best Insulation for Open Exterior Walls

  1. Fiberglass Insulation. Fiberglass insulation is one of the options that is going to require tearing down your drywall. 
  2. Foam Board Insulation. 
  3. Spray Foam Insulation. 
  4. Blown-In Cellulose Insulation. 
  5. Injection Foam Insulation.

Choosing the best insulation for open exterior walls depends on factors like climate, budget, and construction type. Here are some common options:

a. Fiberglass Insulation: Fiberglass batts or rolls are a popular choice for open wall cavities. They’re cost-effective and relatively easy to install. However, proper installation is crucial to prevent gaps and air leakage.

b. Spray Foam Insulation: Spray foam insulation, whether open-cell or closed-cell, offers excellent thermal performance and creates an airtight seal. It’s especially effective in open wall cavities but often requires professional installation due to its specialized equipment.

c. Cellulose Insulation: Made from recycled paper products treated with fire retardants, cellulose insulation is an eco-friendly option. It can be blown into wall cavities, filling gaps effectively.

d. Rigid Foam Insulation: Rigid foam boards, like EPS or XPS, are suitable for open walls. They offer high R-values and can be installed either on the exterior or interior side of the wall.

e. Mineral Wool Insulation: Mineral wool insulation, available in batts or loose-fill form, is fire-resistant and provides good thermal performance. It’s also moisture-resistant, making it suitable for various climates.

The best insulation for open exterior walls depends on your specific requirements. Factors to consider include insulation’s R-value, moisture resistance, fire resistance, and whether you prefer a DIY installation or are willing to hire professionals. Additionally, local building codes and climate considerations should guide your choice. Consulting with an insulation expert or contractor can help you make an informed decision tailored to your project.

Why is my exterior door so cold?

If you’ve noticed cold drafts around your entrance, your front door is likely the reason. Small gaps in the door jambs let cold air in during winter and cool air out in warm months. This makes your home heating and cooling system less efficient all year long.

Several factors can contribute to your exterior door feeling cold:

a. Poor Insulation: Inadequate or worn-out insulation around the door frame, in the door itself, or in the wall cavity can allow cold air to seep in and warm air to escape, making the door feel cold to the touch.

b. Weatherstripping Issues: Damaged or worn weatherstripping can create gaps around the door, allowing drafts and cold air to enter your home.

c. Single-Glazed Windows: If your exterior door has windows, single-glazed ones are less effective at insulating against outdoor temperatures compared to double-glazed or insulated glass.

d. Door Material: The material of the door itself can influence its insulating properties. Solid wood doors often insulate better than metal doors, but their effectiveness can still depend on other factors like weatherstripping and insulation within the door.

e. Exterior Temperature: Extreme outdoor temperatures, especially in winter, can make any door feel cold to the touch, even if it’s well-insulated.

Can you insulate a non insulated door?

You can absolutely insulate the garage door, but you should keep in mind that there are only two materials that work: Mineral wool blankets: A standard product that can be found in a typical hardware or construction store, it is a roll of wool with flexible plastic film coated around it.

Yes, you can improve the insulation of a non-insulated exterior door. Here are some ways to do it:

a. Weatherstripping: Apply or replace weatherstripping around the door frame to seal gaps and prevent drafts. Options include adhesive-backed foam tape, door sweeps, and V-strip weatherstripping.

b. Door Insulation Kits: These kits typically consist of foam panels or reflective barriers that adhere to the interior side of the door. While they won’t provide as much insulation as a fully insulated door, they can help reduce heat loss and drafts.

c. Adding Insulating Material: You can add insulation to a non-insulated door by attaching rigid foam insulation panels to the interior side of the door. Make sure it doesn’t interfere with the door’s operation or locking mechanism.

d. Replace or Add a Storm Door: Installing a storm door on the exterior can create an additional barrier against the elements, improving insulation and energy efficiency.

e. Professional Door Replacement: If your budget allows, consider replacing the non-insulated door with a new, insulated one. This will provide the most effective long-term solution.

How do you insulate a wooden external door?

Adhesive foam strips or draught stripping – This works by sealing around the edges of the doors to fill in the gaps. Simply measure the door, remove the self adhesive and line the edge of the doorway for a snug fit.

Insulating a wooden exterior door involves a combination of techniques to ensure it is energy-efficient:

a. Weatherstripping: Apply weatherstripping around the door frame to seal gaps. This can be done with adhesive-backed foam tape or other weatherstripping materials.

b. Door Sweep: Install a door sweep at the bottom of the door to seal the gap between the door and the threshold.

c. Insulated Door Blanket: Consider using an insulated door blanket or curtain on the interior side of the door, especially during colder months. These are designed to prevent drafts.

d. Insulate the Door Core: If the door is not solid wood, you can improve its insulation by adding an insulating material to the core. Remove the door from its hinges, drill holes, and inject expanding foam insulation into the core. Be sure to follow manufacturer guidelines.

e. Storm Door: Installing a storm door on the exterior can provide an additional layer of insulation and protection.

What is the best treatment for exterior wooden doors?

Paint. Because its opaque pigments block the sun’s UV rays, an exterior-grade oil- or water-based paint is the longest-lasting and most-protective finish you can apply. Plus, it comes in eye-catching colors to improve your home’s curb appeal. Sand and reapply every five to six years.

To protect and enhance the longevity of exterior wooden doors, it’s essential to use appropriate treatments:

a. Paint: Painting your wooden door with high-quality exterior paint is one of the best ways to protect it from the elements. Multiple coats with proper priming can provide a durable finish that resists moisture and UV damage.

b. Stain: If you want to showcase the natural beauty of wood, use a wood stain. Stains penetrate the wood and protect it from moisture while highlighting the grain.

c. Varnish or Polyurethane: Clear varnish or polyurethane coatings add a protective layer to wooden doors. They’re especially useful for doors with intricate woodwork. Ensure it’s suitable for exterior use.

d. Sealer: Wood sealers, such as water repellent preservatives (WRPs), are a good choice for exterior wooden doors. They provide water resistance and protect against decay.

e. Regular Maintenance: Regardless of the treatment used, regular maintenance is crucial. Inspect your door annually for signs of wear, peeling paint, or damage. Touch up any areas that need attention to prevent further deterioration.

The best treatment for your exterior wooden door depends on your aesthetic preferences and the level of protection required. It’s essential to follow the manufacturer’s recommendations for the chosen treatment and perform maintenance as needed to keep your door looking and performing its best.

How To Insulate Exterior Door


You’ve now mastered the art of insulating exterior doors, a skill that will undoubtedly pay dividends in energy savings, comfort, and overall well-being. By diligently following this comprehensive guide, you’ve not only fortified your home against the elements but also taken a significant step towards a more sustainable and efficient living space.

Remember that the benefits of your efforts extend beyond mere temperature control. A well-insulated exterior door insulation also offers noise reduction, improved indoor air quality, and increased privacy, enhancing the overall quality of life for you and your family. Regular maintenance and periodic checks for any potential gaps or wear will help maintain the effectiveness of your insulation over time.

As you stand back and appreciate the fruits of your labor, take pride in knowing that you’ve contributed to a greener and more cost-effective home. The knowledge you’ve gained throughout this insulation journey empowers you to make informed decisions about home improvement projects in the future.

Should you encounter challenges during the process, remember that every DIY endeavor offers opportunities for learning and growth. Troubleshooting and adapting techniques to suit your specific circumstances are integral parts of the journey. Whether you’re a seasoned DIY enthusiast or a first-time insulator, this guide equips you with the foundational knowledge needed to accomplish your goal.

Thank you for entrusting us to guide you through this rewarding journey of enhancing your home’s insulation. As you revel in the increased comfort and energy savings, take a moment to appreciate the positive impact your actions have on both your living space and the environment.