7 Ways Airtightness Improves Your Home
One of the most effective ways to improve your home is to make it more airtight. But airtightness is about much more than reducing your energy bills. I have here a list of 7 ways that airtightness improves your home, and I put energy efficiency at the bottom. That’s because indoor environmental quality generally matters more than the bills we pay.
1. Comfort
With cold weather coming soon, this one’s easy to understand. If you feel cold air leaking into the house, you’re getting a direct message from the world that your air barrier isn’t up to snuff. Cold drafts aren’t pleasant.
But that’s not the only way a leaky house affects your comfort. You also feel poorly insulated floors, walls, and ceilings. Cold air that’s able to find the drywall or subfloor will make those materials cold. Then those cold surfaces suck the heat right out of your body. That’s why I wrote that naked people need building science.
2. Indoor air quality (IAQ)
A leaky house allows easy entry to pollutants from a toxic garage, a damp crawl space or basement, or a dirty attic. These buffer spaces are often full of air pollutants that you don’t want to be breathing.
Even outdoor air, though, can bring PM2.5, ozone, pollen, and other pollutants. It’s no surprise that airtightness is one of my 7 steps to good indoor air quality.
3. Moisture
When you have a damp crawl space like the one in the photo above, a leaky house allows a lot of moisture to get into places where it can do damage. But it’s not just crawl spaces. If you live in a humid climate, any outdoor air that leaks in on humid days can present problems.
Excess moisture in the air can spur microbial growth, make you uncomfortable, and force your air conditioner to work harder. Keeping that humid air out by sealing up those leaks is another way that airtightness improves your home.
4. Durability
When moisture accumulates in porous materials like wood and drywall, it can damage those materials. Liquid water is worse, but humid air can be a problem, too.
5. Noise
Sound waves that reach our ears travel through air. When air connects the indoors with buffer spaces and the outdoors, noises from those spaces will be louder in a leaky house than in one that’s airtight.
Air-sealing is one of the primary ways to soundproof a house. I built an airtight house (1.4 ACH50) a quarter century ago, and it was the quietest house I’ve ever lived in. I remember being indoors one time with the house closed up. Someone drove right up to the house on our gravel driveway, and I didn’t hear a thing until they knocked on the door.
6. Odors
In addition to hot, cold, humid, polluted, or noisy air coming through air leaks, so do odors. Got a smelly garage? A moldy crawl space? Neighbors who grill a lot? Those smells can find their way into your indoor air through the air leakage pathways.
7. Energy efficiency
And finally, yes, airtightness improves your home’s energy efficiency, too. When you have an airtight house, you don’t lose as much of that expensive air you’ve paid to clean, heat, cool, dehumidify, or humidify.
How to make your home more airtight
Now that it’s autumn here in the northern hemisphere, the onslaught is beginning. I’m talking about the slew of articles advising homeowners to caulk the windows and weatherstrip the doors. Don’t fall for it! To improve the airtightness of your house, you have much better opportunities elsewhere.
If you’re building a new home, you may not have an option because a lot of state and local governments have building codes that require airtightness. Many of them also require blower door testing to prove that the builder did the necessary air sealing.
But houses built just to meet the building still may leave a significant amount air leakage through the building enclosure. If you’re working with an architect or builder, let them know you want the house to be airtight. Getting down to 3 air changes per hour at 50 pascals (ACH50) is a good goal. Getting to 2 ACH50 is also doable. Trying to go below 1 ACH50 is doable, too, but it gets significantly harder at that level.
For existing homes, see my articles on air sealing in the related articles section below. Even better, order a copy of my book, which has a lot more information about where and how to air seal.
The good thing about air sealing is that it’s usually a lot less expensive than some other things you can do to improve your home. And depending on your level of DIY skills, you may be able to make a lot of improvement yourself.
Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Georgia. He has a doctorate in physics and is the author of a bestselling book on building science. He also writes the Energy Vanguard Blog. For more updates, you can follow Allison on LinkedIn and subscribe to Energy Vanguard’s weekly newsletter and YouTube channel.
Related Articles
Winterizing Your Home? Don’t Caulk the Windows!
How Airtight Can You Make an Older House?
Why Do Airtight Homes Need Mechanical Ventilation?
Do Airtight Houses Need Makeup Air?
Air Sealing an Attic Access the Right Way
The 3 Rules of Air Leakage (Plus a Bonus!)
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Another great article from Allison, and I agree with all of his points. Air-sealing a house provides many benefits beyond (but not to minimize) energy savings. I air-sealed our first home in Massachusetts, starting with the attic – and we immediately noticed the difference. This resulted in a ‘Pearl Platinum’ rating when it was sold, which added $50K+ to the price.
Our second home in Massachusetts was air-sealed too, based on this experience. Along the shore, air sealing is particularly important for moisture – which rots wood and corrodes steel and aluminum. Windows are key in this equation, because standard double-hung windows do not seal effectively. All of our windows are awning (primarily) or casement (to meet fire escape regs). Both air seal with a compression latch. No drafts.
In short, great job Allison! I hope more people follow your good advice.
Mark: Thanks for adding your confirmation of the benefits!
Nice post Allison! It can’t be said enough….
Thanks, Charles! I agree.
Allison,
Great list. Please consider adding poison free pest control. Air sealing at the building envelope prohibits access to the interior and all interior air sealing limits their ability to move freely from room to room. This works with rodents, cockroaches, and bedbugs, which are the main pests that impact the indoor environment. Air sealing is a key component for Integrated Pest Management (IPM). For reference check out Cornell University’s Stop Pest Program. http://www.stoppests.org
With rodents, air sealing should become slightly more specialized as they can chew through caulk and foam. The addition of a copper mesh to the joint makes it more secure against rodents. Mice only need a hole the size of a dime. https://www.amazon.com/Stuf-Fit-Copper-Mesh-Birds-Control/dp/B0001IMLTY
Armand: Thanks for your very helpful comment! I definitely missed that one, but you and the others who mentioned this spurred me to write a whole article on this topic.
How to Keep Bugs and Critters Out of Your House
https://www.energyvanguard.com/blog/how-to-keep-bugs-and-critters-out-of-your-house/
As an HVAC contractor, I have long advocated for air sealing with the simple, straightforward remark that my crews can easily air condition a house, but not the whole neighborhood.
Curt: That’s a great way to let people know about. I’ve often said that about dehumidification when I see people try to dehumidify a vented crawl space.
You missed the most important one – bugs!
Grant: Yes, you’re absolutely right…so I wrote a new article focused just on that side of airtightness.
How to Keep Bugs and Critters Out of Your House
https://www.energyvanguard.com/blog/how-to-keep-bugs-and-critters-out-of-your-house/
Having an airtight home/building has all of the benefits mentioned, but must have some sort of outside air infiltration system to prevent negative pressures in the home/building from causing even worse issues. We must have proper air infiltration to dilute indoor air or we wind up with a sick building situation. Air to air heat exchangers such as ERV’s and/or HRV’s are the best solution, but even an outside air vent to the return air ducting of the HVAC system is good to provide dilution air. Dilution is the best solution for air pollution.
Robin: Yes, airtight homes need air changes. I’d call that ventilation, not infiltration.
So many HVAC technicians think of ventilation as mostly removing air by means of exhaust fans that I try to specify bringing outside air into a building in a controlled manner as infiltration. But you are correct, the combined movement of the air out of and into a building does fall under ventilation. Unfortunately, proper ventilation is the most neglected part of HVAC.