Air Sealing & Insulation Guide: Types, Methods, Tips, Process & Step-by-Step Guide

Air sealing is getting huge in Canadian households and for a good reason. With rising energy costs and a growing focus on sustainability, people are looking for ways to make their homes more efficient and comfortable.

If you haven’t considered adding air sealing and insulation to your to-do list, now’s the perfect time to jump in.

This guide willinformation walk you through everything you need to know—types of insulation, tips to get it right, and rebate . 

What Is Air Sealing?

Air sealing is the process of sealing gaps, cracks, and holes in your home to stop unwanted airflow. These leaks might be around windows, doors, electrical outlets, plumbing pipes, or your attic or basement. It keeps the warm air in during the cold months and the cool air in summer.

Now, let’s talk about why air leaks are bad. First off, they waste energy. About one-third of the energy you pay for escapes through these gaps. Plus, air leaks make your home less comfy—winter drafts, hot summer spots, and uneven temperatures all year round.

What’s causing all this air to sneak in and out? Three main culprits:

1. Wind: Strong winds can push air into your house on one side and suck it out on the other.
2. Fans: Kitchen and bathroom fans, clothes dryers, and HVAC systems move air around and can accidentally create leaks.
3. Stack Effect: Warm air rises, so in winter, it escapes through the top of your house, pulling cold air in through lower gaps. In summer, it works the opposite way.

Air Sealing vs. Insulation

Air sealing focuses on closing gaps, cracks, and leaks to stop uncontrolled airflow in and out of your home. Insulation, on the other hand, slows down heat transfer to keep your home warm in winter and cool in summer. Air sealing is often considered more important than the insulation.

Most of the time, air sealing and insulation upgrades are done together to maximize energy efficiency.

5 Benefits of Air Sealing Your House

From cutting energy bills to improving comfort and air quality, sealing up your home can make a big difference. Let’s break it down.

Cut Energy Costs

Air sealing can save you serious cash. The EPA estimates that homeowners can save an average of 15% on heating and cooling costs (or about 11% on total energy costs) by sealing leaks and adding insulation in key areas like attics, crawl spaces, and basements.

For example, if your average annual energy bill in Canada is around $2,500, air sealing could save you up to $375 annually. Over time, those savings really add up.

Improved Indoor Comfort

Nobody likes sitting in a drafty living room or dealing with uneven temperatures between rooms. Air sealing creates a consistent barrier that stops cold air from creeping in during winter and keeps cool air from escaping in summer. The result? No more chilly drafts or hot spots—just steady, comfortable temps all year long.

Better Indoor Air Quality

Sealing up your home can also improve the air you breathe. You can eliminate pollutants, allergens, and dust that might otherwise sneak in by reducing leaks. 

Pair air sealing with a good air purifier, and you have a recipe for cleaner, healthier air inside your home.

Increased HVAC System Longevity

When your home is properly sealed, your HVAC system doesn’t have to work as hard to maintain the temperature. This reduces wear and tear, helping systems like heat pumps last longer. 

Moisture Control

Health Canada recommends maintaining relative humidity (RH) below 50% in summer and 30-35% in winter to prevent mould and mildew. Air sealing helps you control where moisture comes and goes.

Methods of Air Sealing Your Home

There are several effective ways to seal up your home, depending on where the leaks are and how durable you want the solution. Here’s a breakdown of the most popular methods and why they’re worth considering.

Caulking

Caulking is one of the simplest and most cost-effective ways to seal gaps and cracks. It’s a flexible material that fills small spaces around windows, doors, and other openings. Caulking typically pays for itself in energy savings within a year.

In most homes, caulking lasts about five years before needing a refresh, though high-traffic or exposed areas might need touch-ups sooner.

Weatherstripping

Weatherstripping involves adding seals around doors and windows to stop drafts. It’s great for moveable parts, like doors that don’t sit flush or old windows with gaps.

For a long-lasting solution, interlocking metal weatherstripping is the way to go. Properly installed, it can last a lifetime and keep air from sneaking in or out.

Spray Foam

Spray foam is a versatile option that expands to fill gaps and seals air leaks effectively. It’s often used in attics, basements, and other hard-to-reach areas where precision matters.

It’s a great choice for larger cracks or areas where you need both insulation and sealing.

Door Sweeps

Door sweeps are strips of rubber, metal, or plastic attached to the bottom of a door. They seal the gap between the door and the floor, blocking drafts and even pests. They’re easy to install and make a noticeable difference, especially for exterior doors or garages.

Airtight Drywall

If you’re building or renovating your home, consider airtight drywall. This method uses gaskets or special caulking during the construction phase to ensure walls are sealed. It’s a long-term solution and works particularly well in new builds.

Chimney Balloon

If you have a fireplace you rarely use, a chimney balloon is a clever way to seal off the flue. This inflatable device blocks drafts and can be easily removed if you decide to light a fire.

What Is the Air Sealing Cost?

Air sealing and insulation typically cost between $1,000 and $6,000. The exact price depends on the size of your home, the materials used, and the complexity of the work. 

Don’t forget to check for rebates and assistance programs offered by local energy or utility companies—these can significantly lower out-of-pocket expenses. For more details, check out our Canadian rebate guide.

The final cost for air sealing your home will depend on:

1. The size of your home and how many leaks need sealing.
2. The materials you choose (e.g., spray foam costs more than caulking).
3. Whether you hire a professional or tackle it as a DIY project.
4. The condition of your current insulation and whether it needs upgrading.
5. Your region’s labour rates and availability of contractors.
6. Rebates or incentives that apply in your area.

Ways to Tell If Your Home Needs Air Sealing

How do you know if your home needs air sealing? Most houses could use it, especially older ones. But there are some clear signs that your home might leak air and cost you money.

• Drafts: Feel a chill near windows, doors, or outlets? That’s a draft—air sneaking in or out of your home.
• Uneven Indoor Temperatures: One room feels colder, while another feels hot? Air leaks could be to blame.
• High Energy Bills: If your heating or cooling bills seem too high, you’re probably losing air (and money) through gaps and cracks.
• Dust Accumulation: Excess dust, especially near vents, could mean outdoor air is getting inside and bringing particles with it.
• Moisture Issues: Condensation on windows, damp spots on walls, or even mould could point to air leaks, letting in unwanted humidity.

How to Locate Air Leaks?

If you’re not sure where the leaks are, consider some testing methods:

• Blower Door Test: Uses a large fan to measure how airtight your home is.
• DIY Smoke Tests: Hold a stick of incense near suspected leak areas. If the smoke wavers, there’s a draft.
• Paper Test: Close a piece of paper in a door or window. If you can easily pull it out without resistance, the seal isn’t tight enough.

While these DIY methods can help identify leaks, a professional energy auditor or contractor can do a more thorough job. They have the tools and expertise to locate hidden leaks and recommend the best sealing solutions for your home.

Checklist for Air Leakage Areas in Your Home

If you’re tackling air sealing in your home, knowing where to look is half the battle. Air leaks can show up in the most unexpected places, so having a checklist can help you stay organized. Below is a breakdown of common areas to inspect, room by room.

Main Living Areas

• Around windows and window frames.
• Baseboards and flooring edges.
• Electrical outlets and light switches.
• Fireplace dampers and around the hearth.
• Wall or ceiling-mounted air vents and registers.
• Gaps where walls meet the ceiling or floor.
• Recessed lighting fixtures in the ceiling.
• Around built-in shelves or cabinets on exterior walls.

Attic

• Gaps around attic access hatches or pull-down stairs.
• Spaces where the roof meets the walls (eaves).
• Around vents or ductwork exiting the attic.
• Openings around plumbing stacks or electrical wires.
• Holes or gaps near chimneys or flues.
• Gaps in or around insulation (replace or add more if needed).
• Cracks or holes in the attic floor or joists.

Basement or Crawl Space

• Gaps around the foundation or sill plate.
• Cracks in the foundation walls or floor.
• Around pipes, wires, or ductwork entering the house.
• Windows in the basement (check both frames and glass).
• Basement door edges and thresholds.
• Spaces around sump pumps or other openings on the floor.
• Vent openings, especially if they’re not properly sealed.

Doors

• Gaps between the door and frame.
• Threshold gaps between the door and floor.
• Missing or damaged weatherstripping.
• Door sweeps on exterior doors (replace if worn or missing).
• Mail slots or pet doors that aren’t sealed properly.
• French doors or sliding glass doors (check along tracks and seals).

How to Air Seal Your Home: Step-by-Step Guide

Air sealing is essential for enhancing energy efficiency and comfort in Canadian homes, especially given the country’s diverse climate conditions. Here’s how to do it:

Step #01: Conduct an Energy Audit

Start with an energy audit, also known as an EnerGuide evaluation, to understand your home’s energy use and pinpoint major leaks.

Hire a professional energy advisor registered with Natural Resources Canada. The process typically takes 3 to 5 hours and costs between $300 and $500. They’ll provide a detailed report on your home’s energy performance, highlighting areas that need sealing.

Step #02: Seal Attic and Roof Penetrations

Always start with the attic. This is often the biggest source of air leaks because of the stack effect—warm air rises and escapes through the roof, pulling in cold air from below. 

• Check for leaks around attic hatches, pull-down stairs, and any openings for wires or pipes. 
• Use spray foam or caulking to seal these gaps. If your insulation is sparse or uneven, add more.

Make sure you address cracks where the roof meets the walls or around chimneys and flues. 

Step #03: Seal Windows and Doors

Windows and doors are notorious for letting drafts in. Start by applying weatherstripping around door frames and window sashes. Use caulking to fill any cracks or gaps you see around the outside of window frames. 

If you feel air sneaking in under your doors, a door sweep can fix that quickly. Sliding doors often have leaks along the tracks, so don’t forget to check those too.

Step #04: Check the Basement or Crawl Space

The basement is another hotspot for air leaks, and it’s one many people overlook. Inspect where the foundation meets the framing above it—this is a common spot for gaps. Seal those areas with caulking or foam. 

Look for cracks in the foundation walls or floors and patch them with masonry caulk or cement. 

Also, check where pipes, wires, and ducts come into the house, as these are often unsealed. Adding insulation to exposed basement walls can also improve energy efficiency.

Step #05: Seal Walls and Floors

Don’t skip the smaller gaps—they add up. Install foam gaskets behind electrical outlets and light switches to stop leaks you might not notice. 

Seal cracks in walls and gaps where walls meet floors or ceilings using spray foam or caulking. Even small details like baseboards can let in air, so check and seal them where needed.

Step #06: Inspect Vents

Vents are another sneaky source of air leaks, especially older ones. Check around dryer vents, kitchen exhaust fans, and bathroom fans. Seal any gaps with caulk or foam. 

If you have vents that aren’t in use, like an old exhaust vent, cover them with an insulated cap. For HVAC ducts, ensure they’re sealed and insulated to prevent air loss.

Step #07: Test Your Work

Once you’ve sealed everything up, it’s time to test and make sure you’ve got it right. A blower door test can measure how airtight your home is now. 

Tips for Sealing Air Leaks in Your Home

Some techniques and tricks can make air sealing more effective and longer-lasting. Here are some practical tips to help you get the most out of your efforts.

• Install a vapour barrier on the warm side of your insulation, especially in the attic. 
• Use mastic sealant or metal-backed tape to seal ductwork joints and seams, especially in areas like attics or basements that aren’t climate-controlled. 
• Apply high-quality acrylic-latex or silicone caulk for sealing small gaps and cracks (less than ¼ inch) around windows, doors, baseboards, and other stationary areas. It’s durable and flexible for long-term results.
• Inspect light fixtures in the ceiling, particularly recessed lighting, for leaks. These are common culprits for air escaping into the attic. Use airtight trims or seal with caulk as needed.
• Use spray foam insulation for larger gaps or holes, especially around plumbing, electrical openings, and attic penetrations.
• Use foam gaskets behind electrical outlets and switch plates on exterior walls to stop air leaks you might not notice otherwise.
• Inspect and seal gaps around plumbing stacks, vent pipes, and other penetrations in your roof or walls.
• Don’t forget about pet doors or mail slots, as these can let in significant drafts. Use insulated flaps or weather-sealing kits to reduce air loss.

4 Myths About Air Sealing Your Home

Let’s bust some myths about air sealing.

Myth #1: My Home Is Too Old to Benefit from Air Sealing

Some people believe older homes are beyond saving in terms of energy efficiency, but that’s far from true. Older homes often have the most to gain from air sealing. They usually have more gaps, cracks, and outdated insulation than newer builds. 

Myth #2: Air Sealing Will Make My Home Too Airtight

Many homeowners worry that sealing their home will make it “too airtight,” but modern homes are rarely sealed to the point where ventilation is an issue. 

Air sealing keeps out uncontrolled drafts, but it doesn’t stop your house from “breathing.” If anything, it makes your home breathe smarter.

Even when a home is well-sealed, controlled ventilation systems like HRVs (heat recovery ventilators) or ERVs (energy recovery ventilators) ensure fresh air circulates properly. 

Myth #3: Air Sealing Is Too Expensive

Sure, the upfront cost might sting a little, but here’s the kicker: air sealing is one of the best bang-for-your-buck upgrades. It pays for itself in energy savings over a few years. Plus, energy providers’ or government programs’ rebates and incentives can significantly reduce the initial cost.

Myth #4: Air Sealing Is a DIY Job for Everyone

While some parts of air sealing can be done yourself, like caulking and weatherstripping, larger or more complex tasks often require professional expertise. Improperly sealed areas or skipped spots can lead to moisture problems or incomplete results. It’s worth calling a pro for a thorough job.

Air Sealing Rebates in Canada

Here’s a breakdown of what rebates are in Canada and how you can benefit:

The good news is that there are various rebates available across Canada to make the process more affordable. Here’s a breakdown of what’s out there and how you can benefit.

Federal Rebates for Air Sealing

Under the Canada Greener Homes Loan Program, homeowners can access an interest-free loan of up to $40,000 to cover the cost of energy retrofits, including air sealing. A pre- and post-upgrade EnerGuide evaluation by a certified energy advisor is required to validate improvements. Keep your receipts, as you’ll need them to apply for reimbursement.

As of October 2024, 55,658 households have implemented air sealing retrofits through this program. 

Provincial and Utility Company Rebates

Rebates for air sealing vary by province and utility company. Here are some highlights:

• Ontario: The Home Efficiency Rebate Plus (HER+) program offers up to $1,300 for achieved air sealing.
• British Columbia: CleanBC Better Homes provides rebates up to $5,000 for insulation and air sealing projects when paired with other efficiency upgrades.
• Newfoundland: Through the takeCHARGE program, homeowners can receive up to $500 for air sealing improvements.
• Prince Edward Island: efficiencyPEI offers rebates ranging from $100 to $700 for air sealing, depending on the percentage improvement in air changes per hour.
• Yukon: Homes that are five years or older can qualify for air sealing rebates of up to $5,000 as part of the Better Buildings program.

How to Apply

To qualify for air sealing rebates:

1. Check with your provincial government, utility provider, or programs like the Canada Greener Homes Loan for eligibility requirements. For more details, check out current Canadian government rebates.
2. Schedule a pre-upgrade energy audit with a certified advisor.
3. Complete the air sealing improvements with a licensed contractor or supplier.
4. Arrange for a post-upgrade audit to validate the work.
5. Submit your application and all necessary documentation to receive your rebate.

Get a Free Quote for Your Air Sealing Project Today!

While small fixes can be done yourself, a professional has the tools and expertise to identify and seal leaks that may not be obvious. 

They know where to look, how to seal those sneaky leaks, and which materials will actually last. 

Get a free quote from a trusted professional today and ensure your air sealing project is done right!