The definitive guide to air sealing your house

Is air sealing worth it? Definitely. Air sealing your house can save you money and create a healthier, more comfortable home. Here’s why.

Is air sealing worth it? Definitely. Air sealing your house can save you money and create a healthier, more comfortable home. Here’s why.

Have you wondered if it’s worth it to add “air sealing house”  to your project to-do list? You should.

Along with insulation, air sealing is one of the most important things you can do to improve your home’s comfort, health, and energy efficiency—and it’s often overlooked by both homeowners and contractors.

Lots of people don’t know the huge impact that air sealing can have on the comfort of their house—and some homeowners even worry that too much air sealing will make their home stuffy or unsafe. (Spoiler: That’s not true.)

Not to worry. In this homeowner guide, we’ll look at all the common air sealing questions—including what air sealing is, if air sealing is worth it, air sealing house costs, the air sealing techniques the professionals use, and more. We’ll even debunk a few air sealing myths along the way.

Here’s what we’ll be covering (feel free to skip around).

  1. What is air sealing?
  2. Why should you air seal your home?
  3. Where should you air seal in your house?
  4. Does air sealing make your home too stuffy or make you sick?
  5. Is air sealing worth it?
  6. What does air sealing a house cost?
  7. Can you air seal your house yourself?
  8. What air sealing techniques do professionals use?

Overall, we’ll be demystifying the task of home air sealing in this comprehensive guide. Let’s get started.

air sealing

What is air sealing?

Air sealing is the process of discovering—and then sealing—all the nooks, crannies, gaps, and open seams throughout your home (and, trust us, you probably have a lot more gaps than you think—more on that later).

A professionally-sealed home will have beautifully regulated air flow—it’ll be less stuffy in summer and less drafty in winter.

Air sealing can also improve your home’s overall air quality, reduce humidity in your house, increase the health and comfort of your home, and cut back on the amount of energy consumed by your heating and cooling equipment.

Air sealing has many benefits—but it’s also highly technical, specialized work, and it takes place in some hard-to-reach parts of your home. So you’ll get the best, most effective results when it’s performed by an experienced professional.

Why would homeowners want to air seal their home? Especially alongside upgrading insulation?

Every house needs healthy airflow. 

Natural airflow helps prevent the buildup of mold and mildew throughout the house, and mechanical airflow (like the vent from your furnace) prevents unwanted and sometimes even dangerous air from remaining trapped in your house.

The trouble is that many houses—especially older ones—have problems with excess airflow. Gaps and cracks in your foundation, attic, and walls joists create little pathways for air to travel through. Discover how to find air leaks in your house here.

Individually, these holes might be tiny—maybe the size of a dime or even smaller—but they add up to a big problem. In fact, we’ve found through our audits of thousands of homes that many houses exchange air at 3–4 times the rate that is necessary; it’s like having an extra window open in your house 365 days a year. That’s a lot of wasted energy (and it’s also inviting moisture and allergens directly into your home).

That’s where air sealing comes in.

Air sealing solves the problem of excess airflow to ensure your house has all the fresh air you need—but without making you uncomfortable. It also helps keep excess moisture out, protecting the structural integrity of your investment and the overall health of your home.

Air sealing attics—one of the biggest culprits to unwanted excess airflow

One of the biggest reasons to air seal and insulate your home is right above you—in your attic and ceilings. There’s a good chance that a lot of heat—as much as 30% to 50% of your home’s heating energy, in fact—is going right up through the attic floor!

That’s because, as heat rises in an under-insulated and unsealed home, it slips through all the little gaps in the ceiling and goes out through the top of the house.

What’s even more alarming is that, as all that heat is escaping through the roof, it creates a giant vacuum effect which actively sucks cold air in from the outside— causing windows, doors and other entryways feel draftier than they actually are. If you’ve ever noticed cold air streaming into your home on a still winter day, that’s why: It’s being physically pulled into your home from the vacuum left behind by all the escaping hot air.

To interrupt this process, you need to do everything possible to keep heated air from rising up and out of your home—air sealing your home as well as installing the correct amount of high-quality insulation is the best one-two punch to make that happen.

Read Why is my upstairs so hot to learn how air leaks contribute to uneven temperatures in the home.

Air sealing attics often includes upgrading insulation for the best results

Ultimately, air sealing and insulation work best when they work together as a team. Insulation works like the down lining in a winter coat, helping lock in warmth in the winter and cool air in the summer, and air sealing is like a wind breaker, stopping excess airflow.

If your house is heavily insulated but lacks proper air sealing, your insulation won’t have the same weather-stopping power. Plus, having a lot of insulation without proper air sealing can create secondary problems like mold and mildew buildup.

Can you air seal your home without adding insulation?

Yes, but they’re usually done together—and for good reason.

Air sealing has great upsides, and many homes need it—but if you air seal a home that isn’t properly insulated, you’ll only reap part of the benefits and won’t be able to fully regulate the temperature in your home. (The best-sealed house in town will still be stuffy in the summertime if its insulation is 100 years old!)

If you air seal your home without looking at the insulation, you might be leaving the job half done.

Where should you air seal in your house?

The short answer: Everywhere there’s a gap. But when air sealing houses, we primarily focus on two areas of the home—the foundation and the attic—and that’s because they’re the two biggest culprits when it comes to undesired air exchange.

Let’s look at the details, briefly:

Foundation air sealing

As your home ages, small gaps and crevices begin to develop in and around your foundation, which foundation air sealing works to resolve. These openings, which are a prime source of excess air flow, are one of the first areas tackled when air sealing a home. When Sealed does the work, we also seal the wooden beam around the perimeter of your foundation so it’s protected from unwanted air entry.

Attic air sealing

Duct work, electrical wiring, plumbing, bathroom vents, and even recessed lighting fixtures create pathways for unwanted airflow—resulting in the “giant vacuum” effect that sucks cold air into your home. Attic air sealing (and duct sealing) solves these issues by plugging these holes with expanding spray foam so excess air can no longer pass through. It’s pretty much magic. (For recessed lighting, the fixtures are capped from above with fire-retardant boxes and sealed around the edges.)

Whole house air sealing: Other areas

Leaky windows and doors can also be a source of excess airflow, especially in older homes. At Sealed, we tackle this problem with another form of air sealing called weather stripping. It’s a quick, easy install—and far more cost-effective than replacing the windows and doors themselves.

Further reading: Do you need new windows? Probably not.

The best way to figure out where to air seal in your home is to get an energy audit from a certified contractor. It’s possible to try to audit your own home, but it’s rarely a good idea.

The professionals know what they’re looking for, they have the right equipment and knowledge to figure out exactly where your energy dollars are going, and they’re willing to crawl into all the least-comfortable places in your home to get the job done right. (Not a small benefit, as anyone who has ever been in an unused attic can verify!)

Ultimately, hiring a professional is worth the investment. And, if you go with a Sealed plan, your energy audit is automatically included. We’ll hire the contractor and stand behind their work 100%—so you’ll know it’s done right.

4 common air sealing myths

Myth 1: Air sealing can make your home too stuffy. 

Many homeowners worry that air sealing can make their house too stuffy or prevent the flow of healthy air throughout the home. Not true! In fact, rather than causing stuffiness, air sealing prevents it.

Without air sealing, warm, humid air can be drawn into the house in summer. In winter, a house without proper air sealing can be freezing on the first floor, and an inferno upstairs.

An important caveat: It is possible to take air sealing too far—it’s called over-tightening.

While over-tightening your home is definitely something to be avoided, it’s just not the big problem that people think it might be—as long as you hire a trained professional.

(Frankly, we’ve found that over-tightening is rarely, if ever, an issue with the homes that we service. Our people know what they’re doing.)

But you don’t have to take our word for it. The Building Performance Institute, the governing body that certifies the home performance contractors we use at Sealed, has clear guidelines and mathematical formulas for preventing over-tightening with air sealing. We follow these standards on every project at Sealed.

Myth 2: Air sealing causes too little air flow throughout the home. 

This is also a common myth. Houses built very recently (with a lot of insulation and air sealing already in place) are at some risk of over-tightening.

So are houses that lack proper mechanical ventilation. However, houses built in the 20th century or earlier often have so much excess airflow that there’s plenty of opportunity to air seal while still maintaining healthy circulation.

Myth 3: Air sealing causes moisture problems. 

Another myth here! It’s actually the opposite: Air sealing helps resolve moisture issues throughout your home when done correctly. The majority of harmful moisture comes from outside air and moisture getting in.

Working with the right contractors who know how to properly air seal and keep outside air out is crucial: If air sealing is done improperly, it can cause moisture and ventilation issues. And this is most likely where this myth originates from.

Myth 4: Air sealing causes sickness in your household if your home is too airtight. 

Absolutely not. Air sealing increases the overall air quality and health of your home when done properly and by experts. Again, it’s technically possible for a home to be over-tightened (especially in newer builds), but when working with a professional, this is unlikely.

Many homeowners worry that air sealing can make their house too stuffy or prevent the flow of healthy air throughout the home. Not true! In fact, rather than causing stuffiness, air sealing prevents it.

Is air sealing worth it?

Yes. Getting your home air sealed is a worthwhile investment—one that pays off in energy efficiency, comfort, and your home’s value.

According to Energy Star, the EPA estimates savings of 15% on heating and cooling costs by properly air sealing and adding insulation. But the value goes beyond dollars and cents. It’s no fun to be uncomfortable in your own house, and an air sealing package can go a long way toward making your home base feel—well, like home

Hear directly from customers we worked with to air seal their home:

“I didn’t realize the basement leakage was as bad as it was—we always had one spot in the front of the house around the baseboard that we could always feel a draft but we could never find it…well the team from Sealed found it. They were fantastic.”

Paul and Kay K.

Can air sealing increase home value?

Air sealing can increase your home’s value because energy efficiency is a growing priority among homebuyers.

In fact, a survey conducted by the National Association of Homebuilders showed that buyers are willing to pay an additional $8,728 upfront on a home in order to save $1,000 a year in utility bills. And, ultimately, 91% of home buyers prefer an energy-efficient home—that’s an overwhelming majority.

So, yes—energy-efficient home improvements matter, and not just in the areas of smart thermostats, the best HVAC systems, and new appliances. Air sealing and attic insulation upgrades can also make a big difference in your home’s attractiveness to buyers.

(And if you want to sell an older home, taking steps to upgrade your energy efficiency before you put it on the market is important—especially if you’re competing with newer homes.)

Learn more about how working with Sealed can increase your home’s resale value.

Air sealing house cost

The typical home air sealing and insulation project could be valued between $5,000–$12,000 USD—when done properly. (And, yes, most air sealing projects also include insulation—the two strategies work together!)

That said, the cost of air sealing varies, depending on the size and location of your home as well as the extent of the project—in other words, whether you’re doing attic air sealing, foundation air sealing, or air sealing the whole house.

The cost of air sealing also depends on what rebates and assistance are available from your local energy/utility companies. The state of New York, for example, offers a variety of financial assistance programs to residents who need home energy audits or energy-efficiency upgrades.

(You can find more information about energy-efficiency upgrade programs in New York here or check out our New York energy rebate calculator.)

However, depending on where you live, you might be able to get your home air sealed at no upfront cost.

Can you air seal your house yourself?

Air sealing is easy to get wrong if you don’t know what you’re doing.

Technically, you could try. But it’s not recommended. 

We might be a bit biased (we’re air sealing experts, after all), but the plain truth is that air sealing is highly technical, time-consuming work that requires technical expertise as well as in-depth knowledge of the way air moves through homes. 

Air sealing professionals get plenty of on-the-job training and experience before they show up at your door. (Sealing a home properly also takes time and persistence. It’s a lot of difficult, unglamorous work finding and plugging all those gaps and crevices.)

Air sealing is easy to get wrong if you don’t know what you’re doing. Remember that open window we talked about earlier in this guide?

When air sealing is done incorrectly—even by the most enthusiastic and confident home-project DIYer—you’ll still have two-thirds of a window open 365 days a year. At that point, you’ve lost time and money, while still not resolving the excess airflow issues in your home.

And, finally, if your air sealing is done incorrectly, you could risk an unhealthy balance of airflow or over-tightening of your home.  

Moral of the story: Consult a professional for home air sealing. It’s worth it.

Air Sealing Techniques: Here’s what the pros do when completing attic air sealing and whole home air sealing.

First, you’ll get an audit. Certified home performance contractors use tools such as thermal detectors to inspect your home, basement, attic, and foundation for air leaks. It isn’t glamorous work. Air sealers need to get into crawl spaces, climb into dusty attics, and squeeze into the darkest basement corners in order to do their job right.

They might also use a fan called a blower door or infrared imaging equipment to determine where the trouble spots are in your home, and they might even perform a building pressurization test.

Then, once the pros determine the airflow trouble spots in your home, they’ll air seal your home with a variety of methods. (Expanding spray foam is one of the most common materials used to seal up your home.)  

Overall, air sealing is highly specialized work. That’s why Sealed only works with certified home performance contractors. Together, we evaluate your house as an ecosystem in which all parts are connected.

Certified home performance contractors are the only people we’d trust with the important work—and they’re the folks we’d recommend even if you choose not to work with us.

Get professional home air sealing and insulation—and only pay if you save money on energy.

Want to learn more about air sealing? Think your house might have too many air leaks?

We’d be happy to help—this is what we do. And, depending on where you live, you may be able to get professional home air sealing, insulation, HVAC, and weatherization upgrades completed at no upfront cost (you’ll pay us back with the money you save on energy). 

Give us a call at 914-353-4835 to speak with one of our experts. Or complete our quick (and easy!) questionnaire to see if you qualify to get energy efficient home upgrades at zero upfront cost with Sealed.

February 24, 2020