Looking down at a ladder from an attic with fiberglass insulation on the floor through an open attic hatch

When insulating your house, you may not consider the attic since you barely spend time there. However, air sealing your attic can provide additional benefits you may not have thought about, so you need to consider all the possible advantages and disadvantages before deciding.

As we learn in BPI certification and energy auditor training – the attic is one of the first places we check for air leakage because it has such an impact on the home’s energy performance.

This article will cover all the different scenarios when you might need to air seal your attic and the advantages and disadvantages it could bring. Additionally, we will give you some tips about air sealing and explain all the costs related to the process. 

We also built a pretty slick home air sealing calculator that uses your own utility bill (and other factors) to show a wealth of data on the benefits of air sealing. You can find that here.

So, let’s begin!

Should You Consider Air Sealing Your Attic? 

Air sealing your attic will help you decrease drafts in the home, increase indoor air quality, save on energy bills, prevent bugs, and will help your HVAC system work less. It will also aid in avoiding health issues and potential damage to the home. However, it can lead to ventilation and moisture problems if done improperly.

Now let’s consider each of these advantages and drawbacks in greater detail.

Pros of Sealing Your Attic

So many problems can be solved by air sealing your attic. If you’re still unsure, seeing all the benefits may help to convince you. 

Better Indoor Air Quality

Air sealing your attic will close the gaps that make the air inside cold during winter and too hot during summer, sparing you discomfort. You also won’t suffer from allergies caused by dry air or the particles that enter through the gaps. 

A homeowner sits on the couch in her living room, appearing satisfied while adjusting her mini-split evaporator with a remote control

An Efficient and Environmentally Friendly Home

You can save significant money by sealing the attic since the air conditioners won’t need to work as much throughout the year. Therefore, your house will be more efficient, and you will reduce its environmental impact. 

To learn more about air sealing your home for efficiency, read our article, Air Sealing Your Home For Efficiency: Your Ultimate Guide.

Less Dusting and Vacuuming

The attic is a common culprit for allowing dust into your home. Therefore, air sealing the attic will close the gaps that let dust in and make it easier for you to handle cleaning around the house. You won’t have to spend time vacuuming the attic dust daily, and you reduce your chances of getting ill from dust particles. 

Two kitties chase the robot vaccum around the living room with reddish hardwood floors.
Photo by YoonJae Baik on Unsplash

Avoiding Structural Damage to the House

Once you air seal your attic, ice damming won’t be a problem. The roof will be isolated from the rest of the house, meaning it won’t be as affected by the temperature inside. As a result, the snow or ice on the roof will melt uniformly once the weather is warmer.

Since there will be no more ice dams, your roof and walls will be safe from any potential damage that the built-up ice could cause. 

Cons of Sealing Your Attic

Generally speaking, air sealing your attic is advantageous, but some issues may arise, especially if the sealing work is not done correctly.

Potential Limited Air Circulation

The biggest concern that may cause you to rethink air sealing your attic is that it might restrict the airflow inside the house. Of course, there is a  risk of the house having limited airflow, but only if the sealing is done poorly. Otherwise, your home will still have a healthy amount of air circulation.

If Done Improperly, It Could Cause Moisture Issues

The lack of ventilation can also cause issues with moisture around the house, leading to potential health problems. Moisture inside can cause your allergies to act up and other respiratory system issues.

However, this problem is avoidable, and if you get qualified contractors to seal the attic, you won’t have to worry about it.

A carpenter installing an attic vent to improve home ventilation

It Can Be Expensive

The cost of air sealing the attic depends on various factors. You’ll save some money if you do it yourself, but professionals may be the safer option if you don’t have the time or the necessary skills. Prices of contractors vary, but generally, they are relatively high.

When To Consider Air Sealing Your Attic

You may not notice it, but your attic can be the source of many issues around the house. 

Although beneficial, attics can also be problematic because they easily introduce gaps and leaks to the house. Additionally, they are not as sturdy as the rest of the house, and people don’t spend much time in them, so many problems go unnoticed.

However, homeowners can usually feel the effects of a poorly sealed attic around their homes. Several signs can tell you when it’s time to air seal the attic.

Let’s look at these poorly-insulated attic red flags.

You Have High Energy Bills

High energy bills are a common problem with many households, and they are caused by different factors. However, one of the variables that may be causing your energy bills to increase is your attic.

If your attic is not air sealed, it provides a way for the outdoor air to enter your house. Attics can have small gaps in them that you may not even be able to see. The warm air that escapes through these gaps during winter and enters during the summer can significantly affect the indoor temperature.

An attic in a home prepared for insulation to be blown in

As a result, your house will always be colder or hotter than it’s supposed to be, even though there’s air conditioning. Your air conditioners will always try to keep the temperature constant, using a lot of energy, while the attic lets the heat pass freely.

You Feel Drafts Inside

If it feels drafty inside the house, the cause may be your unsealed attic. The small gaps in the attic not only contribute to a temperature imbalance but also create actual drafts indoors.

Drafts make your house colder and even uncomfortable to stay in sometimes. Air sealing the attic will solve this issue for you.

Very Dry Interior Air During Winter

The air is always drier during winter because cold air can’t hold the same amount of water as warm air. As a result, you can feel the effect of the dry air on your skin and sinuses, not to mention the uncomfortable static shock.

However, dry air should be less of a problem indoors since it’s supposed to be warmer. If your attic is unsealed, the air temperature drops as the gaps allow heat to escape. Consequently, you feel the effects of dry air even inside.

Ice Damming During Winter

Ice damming is ice buildup at the edges of your roof. It happens when the snow on top of your roof starts to melt and then freezes again when it reaches the eaves of your roof and can cause damage to your roof and ceilings.

One of the causes of ice dams is an unsealed attic, which allows temperature exchange between the roof and the inside, causing the roof to be warmer near the top. Sealing the attic would let the roof stay as cold as it should be and prevent ice from building up.

Dust Build-Up

Dust is present in every house, but some areas may be more prone to this problem than others. For example, if the areas right below the attic are very dusty, the gaps in the attic allow the dust and other particles to enter.

These particles are annoying and can harm your health, especially if you’re allergic. However, once you air seal your attic, the gaps will be gone, and you won’t have to deal with excess dust in your house.

A woman reaching for an inhaler and clutching at her throat.

Tips for Sealing Your Attic

Once you’ve decided to air seal your attic, you need to learn more about what needs to be done in the process. Even if you leave the actual sealing to trusted contractors, it helps to understand some tips to ensure everything goes as planned.

  • Inspect the gaps – search carefully for any cracks in joists, ducts, and vents. Alternatively, you can try finding the openings using light, paper, or even smoke. However, try the most straightforward way first.
  • Pay attention to insulating a slab on the attic floor – the floor will be the thermal buffer between the roof and the rest of the house, so you should use insulation along the floor slabs.
  • Insulate or seal around windows and doors – points of exit and entrance are weaker than the rest of the attic, and they can easily create gaps, so pay extra attention to them.
Closeup on a homeowner applying window caulk to a seam at the base of a window's interior using a caulk gun
  • Seal the most significant gaps first and then continue to smaller ones – the larger holes are the ones that affect the temperature and air quality inside the most, so make sure to tackle them first to see more immediate improvement.
  • If you’re unsure or encounter difficulties, turn to professionals – air sealing the attic can be a DIY job if you know what you’re doing and have all the necessary time and tools. However, you can always call professionals for more challenging issues.

If you’re a DIYer, you might be interested in our article, How To Blow in Attic Insulation on Your Own (9 DIY Steps).

How Much Could Air Sealing the Attic Cost You?

As mentioned above, one of the disadvantages of air sealing the attic is that the initial cost of air can set you back considerably. Naturally, the price will depend on the material you use, the state and size of the attic, where you live, and many more factors.

A technician air sealing by applying metal-backed tape to an cylindrical duct to prevent air duct leakage

Many hire contractors to do the job, which costs more than doing it yourself. You can expect to pay between $3,000 and $12,000 if you hire a contractor. If you do it yourself, you may spend between $250 and $1500.

However, remember that you’ll save money in the long term no matter how much you spend, thanks to lower energy bills. Additionally, sealing the attic will increase the value of your home should you decide to sell it.


Air sealing your attic is almost always a good idea. You’ll have a better quality of life and spend less on energy bills while reducing your home’s environmental impact. Thus, sealing your attic can make your life much easier. 

However, the process may be costly, especially if you hire contractors. Fortunately, you’ll get your money back in no time because of the reduced energy bills.


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