Seal Air Leaks for Energy Savings
Snapshot | Savings | How to get started | Products | Environmental benefits | Take action!
Snapshot
Our homes leak air—lots and lots of air. In the winter, we pay for heat, but much of it leaks out through cracks and gaps in our walls, and around windows and doors. In a typical U.S. home, around 30% of the heated air leaks out within 3 hours.
It's no surprise that sealing these air leaks is one of the most cost effective home improvements you can do. You'll save money immediately, and you'll feel more comfortable. Air leaks create drafts, and when those leaks are sealed, the pockets of cold air disappear.
Air sealing is sometimes called "weatherization." Both terms refer to reducing the air flow from inside to outside your home. Weatherization also entails sealing up the many visible air leaks that can be fixed, such a drafts around doors, small gaps at the window, and so on.
Whatever you call it, be sure to think about those hidden air leaks, too, usually found in the crawlspace or attic that prevent your home from being airtight.
How can you tell if you need air sealing? An energy audit will show you. Or you can wait for a windy day and use a smoke stick. Walk around your house and see where the smoke rides the air currents. You'll be surprised at the hidden paths of air leaks!
While it is possible to air seal a home to the point where there is too little fresh air, this is not a concern in an existing home. The vast majority of homes in the Bay Area have significant air leaks, and even after a round of air sealing, will have adequate fresh air.
If you have concerns about your ventilation, get answers with an energy audit.
Air sealing and weatherization can be done as a do-it-yourself project, but many homeowners will want to hire a professional. They know where to look and have the array of professional products and applicators to do a good-looking installation that provides benefits for years to come.
Savings
Sealing air leaks is one of the most cost-effective ways to save energy. Here's why:
- It has a fairly low up-front cost. Air sealing, including labor, is very affordable.
- It is a sad fact that our homes were not built airtight. Often 25% to 30% of our winter heat is wasted through escaping air.
Air sealing saves the most money for homes with lots of air conditioner use. It's expensive to cool down a house, and the cost of those air leaks really adds up. If you do a light round of interior sealing, you could see a short 1- to 2-year payback. If you hire a professional to sela the harder-to-find places, the payback may be 5 to 7 years. But the results will last longer, as weatherization often needs to be redone every 3 to 4 years.
Air sealing will also hugely improve comfort. With less warm air leaking out, there is no space for cold air to creep in. And air leaks create air movement, so drafts are reduced after a round of air sealing. You'll find those cold corners of your home are much smaller or gone altogether.
Many air sealing and weatherization products wear out in 4 to 5 years, so plan on refreshing the work you do around windows and doors on a regular schedule.
How to get started
Air leaks are most commonly found around windows, doors, fireplaces, and plumbing penetrations (such as behind your washing machine). There are also many air leaks in the building shell, such as in the meeting places of walls and floors, walls and ceilings, corners, and so on. You'll probably want to have a professional address the building shell gaps, as those fixes are more complex.
An easy way to get started is to inspect your home. Do you see daylight under your front door? Can you feel air movement with you hands around the windows? These simple tests will identify your lighter air-sealing targets.
To find more air leaks, you can buy and light a smoke stick and walk through your house with it. When you see smoke riding the air current and out of your house, you've spotted a leak. When using the smoke stick, run your furnace and/or wait for a windy day to create air movement in your home.
A smoke stick test for air leaks around windows.
Source: Chimney Balloon
Ready to dig deeper? Here some clues to larger air leaks:
See the gap around the black plumbing pipe in the attic? Air leaks around this pipe down into the house. (Photo: Ennovationz)
Notice the black soot and dirt marks on the insulation. This is where dirt collects, deposited by air leaks. (Photo: Ennovationz)
Energy audits can provide a a more precise answer about the size of your air leak problem, and to uncover those almost-hidden leaks to the crawlspace and attic, as shown in the photos above. The technician will use a Blower Door™, a large fan inserted into a doorway, to measure inflow and outflow of air into your home. The test results are even more helpful when an infrared camera is used at the same time. Call Ennovationz to evaluate your options. Or talk to your energy audit technician about whether this level of testing is right for you.
The Blower Door test uses a large fan (the yellow circle at the bottom of the red canvas door cover) to measure air flowing in and out of the home.
The thermal images from an infrared camera can be very revealing. Look at the air leaks around this recessed light!
Recessed lights are a common source of air leaks. The yellow area on the thermal image is the cold air leaking in from the attic. (Photo: Ennovationz)
To get started on your air-sealing project, either head to the local hardware store or get an energy audit. Want advice? Call Ennovationz. (It's free!)
You'll find an array of weatherization and air-sealing products—weatherstripping, caulking, electrical plate insulatators and more—at the local hardware store. Read the labels carefully as the temperature and humidity levels at the time of installation will affect performance and longevity.
Air-sealing products
Every home is a bit different, and our homes leak air in many different ways. While most homes have at least few large air leaks in the attic and crawlspace, here are some interesting products for other places in your home.
• Door shoe: Fits under an exterior door, sealing the air leak between the floor and the door.
• Door sweep: Great for uneven floors as the soft brush closes the air gap but is flexible when the door swings across the uneven floor.
• Draft stoppers: Great for doors that are seldom used.
• Chimney cap damper: Chimneys are a big source of air leaks, and a cap on the top of your chimney will cork those leaks up! A handle comes down the chimney, and simply pull it when you want to have a fire.
Environmental considerations
Air sealing is one of the easiest ways to reduce your carbon footprint. It is cost effective, and many homeowners can do a round of air sealing on their own. Hiring a profesional will reduce your energy use and carbon footprint even more.
