Should I Air-Seal My Attic?

There are lots of reasons why you might be looking into an air-seal for your attic. You might be dealing with inconsistent temperatures in your home during summer and winter. You may be considering upgrading your attic insulation already. Or, perhaps you heard that an air-seal can help your house be more energy efficient, and you want to learn more.

South Central Services has insulated hundreds of new construction and retrofit attics. Whether we're removing existing insulation for an upgrade or insulating things right the first time, our team always installs an airtight seal in the attic. There are many reasons why it is worth investing in an air-seal for your attic.

By the end of this article, you will understand:

• What is happening to your home without an air-seal in the attic
• The benefits of air-sealing your attic
• The drawback of air-sealing your attic
• Whether or not air-sealing your attic is within your budget

What Happens When An Attic Isn’t Air-Sealed?

Many homes do not have an airtight seal in the attic. Air-sealing is a more modern concept that most existing homes in southern PA have not adapted to yet.

No matter the state of your insulation, your home is subject to the stack effect. The stack effect explains how air travels through a home, depending on the temperatures inside and outside. When a house has air leakage, the stack effect is amplified.

Let's say that you live in a two-story home. When your attic has no air-seal, your first and second floors rarely have the same temperature. It doesn't matter what you set your thermostat to. In the summertime, your first floor is comfortable and your second floor is toasty. In the winter, this reverses, with the upstairs being more comfortable and the downstairs feeling drafty.

Even in a one-story home, the result of air leakage and a lack of air-sealing can be felt. Summertime means oppressive heat pushing into your living space from your attic floor. And in the winter, all the heat you pay for seems to dissipate almost immediately.

With the stack effect, hot air is either drawn to the cool air inside or outside of your home. In summer, the heat of your attic pushes into your living space. In the winter, the heat you pay for escapes through the attic.

If you want to limit the impact of the stack effect on your home, you need an air-seal in your attic. Let's examine the pros and cons of investing in an airtight seal upstairs.

Pros Of Adding An Air-Seal To Your Attic

There are so many benefits to air-sealing your attic, whether you insulate the floor or the ceiling. Some of these benefits include:

1. Lower energy costs
2. Increased home comfort
3. Better indoor air quality
4. Less HVAC cycling
5. Tax credit eligibility

Let’s examine each of these pros in more detail.

1. Your Energy Bills Will Be Lower.

Air-sealing your attic stops air leakage. By stopping air leakage, you can stop energy waste. This is not to say that air-sealing your attic will prevent all energy waste in your home. Rather, an airtight seal upstairs stops prevalent air leakage because of the stack effect.

If you put an air-seal in your attic, heat cannot press into your living space during the summer. Attic heat will stop either at your roof or your attic floor. Similarly, in the winter, heat will not be able to escape through the attic. There will be a barrier preventing unwanted air exchange.

Anytime air leaks from your home, you lose the air you pay to condition. An air-seal in your attic means you spend less money on conditioned air because your home holds onto the conditioned air for longer.

2. Your Home Will Be More Comfortable.

We don't always make the connection between comfort and attic insulation. In some homes, attics are hard to access and rarely thought of. However, due to building science, your attic insulation plays a huge role in your home's comfort.

Comfort is also hard to quantify. You can measure the difference in your energy bills before and after an air-seal. You cannot easily measure comfort. Comfort is something that we feel.

For those living in two-story homes, an air-seal in your attic is the first step to feeling comfortable on both floors, no matter the time of year. You won't have to break out extra blankets when it is below freezing outside or break a sweat in your living room in the heat of July. Imagine setting the thermostat and not needing to touch it again!

3. Your Indoor Air Quality Will Be Better.

Air leakage doesn't only contribute to high energy costs and home discomfort. Leaking air also means air quality issues.

We can discuss outdoor air pollution in our area, like burning trash, farmland, and factories. No one wants to take a deep breath inside their home and smell those odors. However, when we talk about indoor air quality improvement, we go back to the stack effect.

When heat escapes through the attic in winter, air must be pulled into the home from somewhere else. Otherwise, there would be negative air pressure in your home. The primary place replacement air is pulled from in the winter is your basement or crawl space.

Most crawl spaces are musty, but some also have mold and mildew. Anything you can do to suppress the stack effect will prevent you from breathing in dirty crawl space air. You can also encapsulate your crawl space to make that air cleaner. But your attic is the most effective first place to insulate in your home.

4. Your HVAC Will Cycle Less Often.

Does your HVAC system kick on and never seem to turn off? Or does it turn on and off constantly throughout the day? Instinctively, you might think something is wrong with your HVAC system. But the first change you should make in your home is actually with your insulation and air-sealing.

Without an airtight seal in your attic, your home is susceptible to uncontrollable air exchange. It is similar to running your air conditioning with the windows open. Your AC cannot keep up with the influx of warmer air.

When you add an air-seal to your attic, you stop a significant amount of air exchange. Fewer air exchanges mean your indoor temperatures stay more consistent. Your HVAC will not have to work as aggressively to keep up with temperature changes if there is less fluctuation.

5. Your Upgrade Will Be Eligible For A Tax Credit.

Cost may hold you back from investing in an air-seal. Many of us are looking for ways to cut costs. We must work within a budget even as we're trying to lower our energy bills.

The great news is that air-sealing qualifies for a federal tax credit. This tax credit will run through 2032, covering all sorts of home energy efficiency upgrades. Air-sealing falls under the insulation upgrade category. You can save 30% of your project cost, up to $1,200 total. An air-sealing project that costs $4,000 would maximize this tax credit.

Cons Of Adding An Air-Seal To Your Attic

There are few drawbacks to air-sealing your attic. However, we did identify one con that may be difficult to move past: replacing existing insulation. Let's examine the drawback to attic air-sealing in more detail.

1. You Will Have To Replace Your Existing Insulation.

You may have made a significant investment in attic insulation already. Perhaps you've layered the attic floor with blown-in or have had fiberglass batts installed.

On the other hand, you might not even know the current state of your attic insulation. No matter where you're coming from, all of your existing attic insulation must be removed to install an air-seal.

There is no way to reuse the insulation in your attic currently. That can be a tough pill to swallow for anyone who just spent money on an upgrade without an air-seal.

It is also important to note that adding an air-seal to your attic doesn't just refer to the air-seal. By adding an airtight seal to your attic, you are also investing in new insulation. Your new insulation could be rather pricey, depending on which product you choose.

From our perspective, as professionals who work in home energy efficiency every day, an air-seal in the attic is a no-brainer. Even with the cost and effort of replacing your current insulation, there are many long-lasting benefits, including financial savings.

Air-Sealing Is Worthwhile, Especially In Poorly Insulated Houses.

Those living in houses with little to no insulation will benefit most from an air-seal in their attic. When you start with a leaky home, changes in air leakage make significant differences.

As a house becomes more airtight, the benefits of air-sealing upgrades start to plateau. In all likelihood, air-sealing your attic is the first air-sealing upgrade you have ever considered. You will probably see a drop in your energy bills between 30% and 70%, depending on the current air leakage and the state of your insulation.

In contrast, if you had air-sealed every other part of your thermal envelope, your attic would not have quite as dramatic an influence on your energy costs.

If you could relate to the descriptions of sweating in your own home and having inconsistent temperatures, air-sealing your attic should deliver substantial results.

You Can Get An Air-Seal For Your Attic, No Matter Your Budget.

At this point, the only thing holding you back is probably cost. If you can lower your energy bills, have better air quality, and be more comfortable at home, why not invest?

When working with South Central Services to upgrade your attic with an air-seal, you can choose between two insulation products: spray foam and blown-in cellulose.

Spray foam is an all-in-one product that delivers an airtight seal and insulation. Blown-in cellulose cannot provide its own air-seal, so we always pair our blown-in insulation with an air barrier.

Blown-in cellulose is more affordable than spray foam insulation. We recommend looking into blown-in paired with an air-seal if you have a tighter budget.

Spray foam insulation is pricier, but it does offer some additional benefits. If you are less concerned about cost, consider insulating your attic with either open cell or closed cell spray foam.

The Bottom Line About Adding An Air-Seal To Your Attic

Attics play a crucial role in energy efficiency in a home. Because of the stack effect, attics contribute to air leakage all throughout the year. Getting an air-seal in your attic will make your home less leaky. Fewer air leaks mean lower energy costs, increased comfort, improved air quality, and less HVAC cycling.

It is important to know that air-sealing your attic is still an investment, especially because you'll need to replace your existing attic insulation. However, you are likely to make your investment back through your upgraded insulation and airtight seal.

Now that you understand why you should air-seal your attic, your next step is to:

• Discover how much money insulating with spray foam really saves
• Learn why homeowners trust South Central Services for their attic insulation