10 Common Air Leaks Found During Blower Door Tests (And How to Fix Them)

Summer in the Dallas-Fort Worth metroplex. The sun beats down relentlessly, and your AC works overtime, struggling to keep your home cool. Sound familiar? Like many homeowners in the DFW area, you're probably wincing at your rising energy bills. You might be thinking about Sarah, a typical homeowner in the suburbs.

She’s concerned about her energy bills and is looking for practical, straightforward advice on home improvements. While she cares about the environment, her main motivation is reducing her monthly costs.

She’s tech-savvy enough to research solutions online and is looking for clear, trustworthy information about home improvements that offer a good return on investment, from simple DIY fixes to larger projects like solar panels or efficient HVAC systems.

High energy bills are often a sign of hidden air leaks, and one of the best ways to find those leaks is with a blower door test. This is a key component of weatherization, which aims to reduce energy consumption by pinpointing inefficiencies and making necessary repairs or modifications.

Weatherization can lead to significant savings on utility bills, with an average drop of 20 to 30%, and in some cases, as high as 60%. Let’s dive into what a blower door test is and explore 10 common culprits that contribute to energy waste in homes.   

What is a Blower Door Test? 

A blower door test is a diagnostic tool used to measure the airtightness of a building. A powerful fan is temporarily installed in an exterior door, depressurizing the house. This creates a pressure difference between the inside and outside, forcing outside air to leak into the house through any openings. Technicians then use specialized equipment to pinpoint the location and severity of these air leaks. This test helps determine how “leaky” your home is by measuring the air loss in the entire house. In addition to the blower door test, a duct leakage test is also performed to measure air loss in the duct system. Both tests help determine the energy efficiency of your home and give a clearer picture of how much you can potentially save from weatherization.   

• How it Works: The fan pulls air out of the house, creating negative pressure 
  . Air from outside then rushes in through cracks and gaps. 

• Benefits: Blower door tests are invaluable for identifying hidden leaks you might not otherwise find. They quantify the amount of air leakage, which helps prioritize repairs and estimate potential energy savings. They also help determine the air changes per hour (ACH) and how this relates to energy efficiency. 

• Square Footage and Leakage Rate: Larger homes naturally have more surface area and thus, the potential for more leaks. Blower door test results often consider the home’s square footage to normalize the leakage rate. A tighter home will have a lower ACH. 

Here are 10 common areas where air leaks are frequently found during blower door tests: 

1. Around Windows and Doors: Gaps around windows and doors are classic entry points for drafts. 
    

• Solutions: Apply weather stripping around the frames and use caulk to seal any cracks.   

2. Attic Access Hatch: This often-overlooked area can be a major source of air leakage. 
    

• Solutions: Add weather stripping around the perimeter of the hatch and insulate the hatch door itself. 

3. Recessed Lighting: Recessed can lights, especially older models, can leak a significant amount of air. 
    

• Solutions: Use airtight recessed cans or seal around existing ones with caulk or specialized gaskets.   

4. Plumbing and Wiring Penetrations: Where pipes and wires pass through walls or ceilings, there are often gaps. 
    

• Solutions: Use caulk, spray foam, or other sealants to fill these gaps.   

5. Fireplaces and Chimneys: Fireplaces and chimneys can be significant sources of air leakage, even when not in use. 
    

• Solutions: Ensure the damper is closed tightly when the fireplace is not in use. Consider having a chimney sweep install a top-sealing damper. 

6. HVAC Ductwork: Leaky ductwork, especially in unconditioned spaces like attics or crawl spaces, can waste a lot of energy.   

• Solutions: Seal duct joints with mastic sealant or metal tape. Insulate ducts in unconditioned spaces.   

7. Electrical Outlets and Switches: While seemingly small, these openings can contribute to air leakage. 
    

• Solutions: Install foam gaskets behind outlet and switch covers. 

8. Baseboards and Trim: Gaps can develop between baseboards, trim, and the wall. 

• Solutions: Caulk along the edges of baseboards and trim to seal any gaps. 

9. Gaps in Exterior Walls: Cracks or holes in exterior walls can allow air to leak in. 
    

• Solutions: Inspect exterior walls for any damage and repair as needed. Use caulk or other appropriate sealants. 

10. Around the Sill Plate: The sill plate, where the house framing meets the foundation, is another common area for air leaks. 
     

• Solutions: Seal the gap between the sill plate and the foundation with caulk or spray foam. 

Blower Door Test Results and Interpretation 

Blower door test results are often presented as Air Changes per Hour (ACH) or Cubic Feet per Minute (CFM) of air leakage. A lower ACH or CFM value indicates a tighter home. These results provide valuable information about your home's energy efficiency. It’s important to have a professional interpret the results and recommend specific solutions for your home. 

Conclusion 

Addressing air leaks is crucial for improving energy efficiency, reducing your energy bills, and creating a more comfortable home. A blower door test is a valuable tool for identifying and quantifying these leaks. If you're ready to improve your home's energy efficiency and comfort, visit our contractor directory to find qualified and experienced contractors in the DFW area who can help you with your weatherization needs.