How much does it cost to seal air leaks in a house?

Reviewed by Cristina Miguelez remodeling expert. Written by Fixr.com.

Air sealing, or air infiltration, reduces unintentional leaking of air in and out of a house. The air may start leaking through cracks and openings, so by sealing them, the house becomes more energy-efficient, durable, comfortable, and has a healthier indoor environment. Sealing the problematic areas where air leaks happen also lowers utility bills.

The national average cost to air seal a home is between $600 to $2,300, with most people paying around $1,450 to seal the interior and exterior walls in a 1,500 sq.ft. home. At the low end of the spectrum, you pay $200 to air seal the ductwork in a 1,500 sq.ft. home. At the high end, you pay up to $7,500 to air seal the basement and the attic.

House Sealing Price

What Is Air Leakage?

Many homes have holes in the building envelope or the exterior walls, roof, and foundation. These openings range from large, conspicuous holes to tiny, almost invisible cracks. However, even the smallest cracks in your walls, floors, and roof can cause problems. Air leakage happens when air enters or leaves through cracks, gaps, or other openings in your home. This means that the floors, walls, or roof aren’t sealed properly, allowing the air to leak uncontrollably inside or outside the home.

In winter, the heated indoor air will escape, and cold air will enter the house. In summer, cool air will leak out, and hot air will move in. If you notice that it becomes difficult to control the air temperature in your home, you may have some problem areas where the air is flowing in and out of your home. Air leaks also cause moisture to seep into the walls and ceiling. If you see mold forming, make sure to call mold remediation services and seal the areas where air leaks before it causes structural damage to the house and affects the health of the occupants.

Home Sealing Cost by Method

Professionals use several methods and techniques to seal a home, ranging from $0.16 to $25 per linear foot, $0.25 to $1 per sq.ft., or $0.40 to $1.50 per board foot depending on the material that will be used. Some methods are more appropriate for specific parts of the building than others. Your contractor will locate the air leakage area, assess the severity of the leak, and determine the most appropriate approach to seal the crack or hole. Below is a table with the most commonly used methods by professionals, how they are done, and how much each of them costs.

Weather Stripping

The average cost of weather stripping is $0.16 to $25 per linear foot, depending on the material used for the sealing. With weather stripping, you’re ensuring that the windows and doors in your home are properly sealed and fit inside their frame. It’s an efficient way of sealing the air gaps around your windows and doors to prevent leaks. This prevents air from flowing in and out of the home uncontrollably and improves energy efficiency.

Rigid Foam

Rigid foam is a durable and effective insulation material that costs $0.25 to $1 per sq.ft. Unlike spray foam that is applied wet and hardens afterward, rigid foam comes as a pre-made hard foam panel that is cut into pieces according to the sealing needs of the project. It’s usually used in new construction projects and unfinished walls, although it’s not the best fit for hard-to-reach areas.

Spray Foam Gap Filler

Filling gaps with spray foam costs homeowners between $0.40 and $1.50 per linear foot. It’s typically sprayed around pipes, plumbing, sills, framing, and ductwork. But it’s also extremely efficient in sealing gaps where air can leak. This is around wall joints in the garage ceiling, around electrical and gas penetrations, or where the foundation and the siding of the home meet. Once sprayed, the foam expands to fill in the gaps and prevents air from coming in and out of the home through it.

Caulking

Caulking costs $1.15 to $3.50 per linear foot. The term caulking refers to various sealing agents that don’t expand and contract as other materials like spray foam. This method seals and closes gaps in buildings and other structures that may allow water, air, dust, or insects to enter. During the application of caulk, the professional uses the appropriate method and tool to apply the sealing material that would be most efficient in the project.

Metal Flashing

Metal flashing used to seal a home costs $10 to $25 per linear foot. Metal flashing is a thin sheet of metal used around the edges and junctions of the roofing material to prevent water or air from entering the house through those joints. Flashing seals the gaps around the flue and chimney, so no air goes through them and compromises the air temperature inside the home.

House Sealing Price by Location

The cost to seal the air leaks ranges between $200 and $4,000, depending on the location of the leakage. Some areas make it easier to access and seal holes. Other areas like attics and crawl spaces can be tricky to access, which increases the costs to seal the air leaks. Below is a breakdown of the most common places where homeowners need to look for air leaks and the cost to seal each of these areas.

Duct Sealing

If you want to maximize energy efficiency in your home, sealing the HVAC systems and ductwork will cost $200 to $400 per project. The ductwork may have holes, cracks, or seams through which air may escape before reaching the desired rooms. To avoid this, they need to be tightly sealed to ensure they keep the conditioned air protected and within the home. Typically, the contractor uses aluminum duct tape, insulation, and ductwork mastic for the sealing project.

Air Sealing Interior Walls

To seal the interior walls in a home, you can expect to spend between $200 and $800. Although not all interior walls in a home require sealing, the most common area that requires this is where the interior walls meet the attic. This is where air most commonly leaks into the home, so the contractor fills in the gaps and voids that compromise the air quality and temperature.

Air Sealing Exterior Walls

The cost to insulate exterior walls in a home is $400 to $1,500, depending on the scope of work and sealing needed. Rigid foam, spray foam, or caulking will be used to seal any exterior walls, roof, or foundation to provide a layer of protection against moisture and prevent leaks. Sealing this area of the home is extremely important to ensure it’s properly and fully insulated to avoid paying high utility bills.

Attic Air Sealing

The cost to seal an attic is $500 to $3,500. Many of the air leakage problems result from a problem with the attic, so it’s a good idea to start your air leak sealing project from here. The contractor starts by filling in the larger gaps and moves towards the smaller ones. Most homeowners seal and insulate the attic during renovation projects as it’s a great time to insulate the attic and other areas of a home. EPA recommends sealing the attic first before adding insulation to maximize efficiency and reduce costs.

Basement Air Sealing

Sealing the basement or crawlspace in your home costs between $800 and $4,000. A basement air sealing project gives significant benefits if done correctly, as it improves the tightness of the house and minimizes bills. When sealing the basement, the contractor seals up the inside of the basement wall, ceiling, and floor. They secure the insulation between holes in rim joists to ensure it stays in place and seals any other holes or cracks that may cause leak issues.

Air Sealing House Labor Cost

The average cost to seal a home is $600 to $2,300. Out of this, $100 to $1,000 is the cost of labor involved, while the rest is the cost of materials. The average project involves the contractor assessing the areas where sealing is needed and using the appropriate method to seal the interior and exterior walls. Most contractors give a quote based on the work needed, hours required, total square foot area, and cost of materials.

Before starting, it’s advisable to do an energy audit that determines the energy efficiency of your home and the problematic areas that need sealing. If the audit determines that windows and doors have air leaks, the professional will apply caulk and weatherstripping. Air leaks around plumbing, ducting, or electrical wiring through walls and ceilings will be sealed with caulk. If you find leaks in your insulation, seal them with spray foam and end drafts from outlets and switch plates by installing foam gaskets behind them. The contractor ensures that the flue damper is tightly closed when you are not using the fireplace to prevent air from flowing in.

Factors that may affect the job are the location of your home, the work needed to seal the house, how many hours the contractor will spend, and the square footage of the home. After the contractor determines the problematic areas, they decide which method, technique, and material will be most fitting for the project, which will also affect the overall cost of the project.

Home Sealing Service For Pest Control Cost

The cost of pest control sealing services starts at only $50 and can go up to $1,000 and higher depending on the number of entry points that need sealing. Also known as pest exclusion, this service is designed to seal any cracks, holes, or gaps in your home through which bugs and rodents may enter. It takes care of the areas in the roof, windows, doors, or similar points of entry to guarantee that no infestation happens. Pest exclusion is typically done by pest extermination services and provided by separate, independent contractors licensed to perform these services.

Is Air Sealing Worth It?

Air leaks drastically increase the heating and cooling costs in your home. The added costs go as high as 40 percent of the total heating and cooling expenses, showing the importance of proper air sealing. In addition to this, air sealing a home comes with other benefits. A tight house has fewer drafts, is more comfortable, has a better performing ventilation system, and requires more affordable and smaller heating and cooling equipment. Sealing a home reduces the chance of mold and rot forming. When you seal the cracks and holes, moisture is less likely to become trapped in cavities and cause structural damage or health issues for the people living in the home.

As good as air sealing may be for temperature control and heat loss prevention in a home, it comes with one major downside. By sealing the air in a home and preventing it from escaping, you prevent harmful particles and contaminants from exiting the house as well. Unfortunately, this means that they will be trapped in the home with no way out, which can harm the indoor air quality and affect people’s health.

Energy Audit Price

The average energy audit costs about $145 to $420. An energy audit helps you understand how much energy your home uses, where you are losing energy, and what changes can make your home more energy-efficient and comfortable. Doing an energy audit before sealing the air leaks identifies areas that may cause air leakage in your home. The contractor knows where to focus their attention and what to do to improve the situation in your home. Most energy audit packages include a blower door test to check for air leaks and measure the tightness of a home, infrared imaging to detect loss of heat from the home, a room-by-room visual inspection of windows, doors, and appliances and utility bill analysis.

Enhancement and Improvement Costs

Attic Insulation

The cost of attic insulation ranges between $1,700 and $2,000. The attic is one of the most common areas where leaks happen and offers the most opportunities to save energy. EPA recommends air sealing the attic before adding insulation to maximize the energy efficiency of the project. Adding insulation after sealing minimizes the chance of ice dams forming in winter, which can be potentially dangerous for the surroundings.

Home Insulation

On average, the cost of insulating a home is $3,500 to $4,500. This includes the cost of insulating the attic and walls and conducting an energy audit. Insulating your home is the most practical and affordable way to make your house more energy-efficient. By sealing the cracks and holes, you prevent hot air from escaping in winter and entering in summer. This helps towards the insulation of a home, which acts as a barrier for heat flow. Properly insulating the entire home reduces your heating and cooling bills by as much as 80%.

Additional Considerations and Costs

• Air sealing vs insulation. While often mixed, air sealing and insulation are different projects. Air sealing prevents air leakage into and out of your home by sealing all gaps, cracks, and seams, while insulation in a home offers resistance against heat flow.
• DIY. This can be a DIY project, especially if you handle small cracks and have the proper equipment. The Department of Energy has resources available for those wanting to seal and insulate their home. However, it’s advisable to hire a professional to maximize the efficiency of the sealing.
• Incentives and rebates. Several rebates and incentives are offered if you insulate your home by hiring a licensed contractor. To qualify, you should hire a qualified contractor certified to conduct an air leakage test.
• Older buildings. Buildings older than 2012 weren’t built with the mandatory insulation requirements set with the adoption of The 2012 International Conservation Energy Code. As a result, they are at greater risk of having air leak problems than homes built after 2012.
• Heating loss. In homes with air leaks, hot air may escape through the cavities, also known as heat loss. According to the ENERGY STAR program, most people could reduce their annual heating and cooling costs by 15 percent by fixing air leaks.