Blower Door Tests Save Energy

Would you trust a doctor who wrote a prescription without running any tests? Of course not! Yet, most homeowners do the home energy equivalent when they call a window company, or an AC company to “make their house cooler” without a test. 

A Blower Door Test is a diagnostic tool that measures your home’s airtightness, revealing where energy is wasted. In this guide, we’ll explore the benefits, process, and real-life impacts of blower door tests, and how they can save you money.

Key Insights:

• The average Blower Door Test costs between $200 and $450, a cost-effective way to enhance your home’s energy efficiency.
• Energy savings of 30%+ are common when sealing leaks identified by blower door testing.
• A more comfortable home is another huge bonus, eliminating drafts and maintaining consistent temperatures throughout your living space.
• Conduct a Blower Door Test with a certified professional - it’s not a simple procedure and requires correct prep to set up and interpret the results. 

What is a Blower Door Test? 

A blower door test measures the air tightness of buildings by trying to suck air out of them. Homeowners perform them so they can identify air leaks.  By identifying air leakage in your home, you can improve energy efficiency, indoor air quality, and overall comfort. 

The two biggest manufacturers are JL Conline and Minneapolis Energy. They’re not DIY friendly as the blower doors themselves cost $4000 - $6000. A test (commonly called an “energy audit” in the industry) will probably set you back around $500.

Resi Report Tip: A blower door test is not something you can “measure the ROI,” like insulation, or new windows. So why pay for one? to answers the question: if I spend $1000, $5000, or $10,000 to make my home more efficient, where will I get the best bang for my buck?

"When you hook up this blower door tester, it's a metal frame with an airtight canvas that takes the place of your front door.” Says Cody Bridwell of Blown Away Insulation. “There's a blower door fan with sensors that pull air out to a measurement of 50 Pascal, simulating a 20-mile-per-hour wind blowing on your house." The sensors measure airflow past the fan, and proxies how air-tight your home is. 

Air Tightness Matters - Save Money, Better Health

Most homes are so leaky, it’s equivalent to leaving a window open 24 hours a day. Energy Star notes that air leakage accounts for 25% - 40% of residential energy usage per day.

Figuring out where air is leaking, and how to stop it is the goal of a home energy audit.

"The Texas standard for new homes is a blower door test of 5… most homes in America are achieving a blower door score of 12 to 19, which is quite inefficient," Cody explains.

These results are measured in ‘air changes per hour’ (ACH) - Generally, lower is better. We’ll discuss what that means later in the article.

Health Benefits

Air leakage often causes airflow between the hot, and dusty attic and the main living spaces. When leaks are sealed, it forces more of the conditioned air to go through AC filters - improving air quality.

Poor indoor air quality can be a huge issue for at-risk homeowners. “We’ve had cases where … asthma and allergies died down after air sealing because your dust level drops significantly” 

A properly conducted blower door test will help pinpoint these leaks. Better air quality means better comfort!

What to Expect During a Blower Door Test

The blower door test involves 4 steps:

1. Setup: A door frame with a powerful fan is installed in the main exterior door.
2. Pressure Testing: The fan creates a pressure difference, pulling air out of the house.
3. Measurement: An airflow manometer measures the rate of air infiltration, revealing how much air is leaking into the house.
4. Results: Your results are provided in “Air Changes per Hour”

“If the air gets easily replaced, it shows a lot of air leakage in your home,” says Cody. "If it’s harder [for the blower] to replace that air, then you have a tighter-built house, and your home is more energy efficient."

What to Do With Blower Door Test Results

The results of a blower door test are expressed as Air Changes per Hour (ACH). 

"ACH means the entire air in your living space is being replaced with new air coming in from the air leakage," Cody explains. “So an ACH score of 8 means that the air in your home would be replaced 8 times every hour with outside air or attic air.” 

Because your air conditioning system ends up cooling that air, higher scores also mean your AC system is working harder than it needs to and might wear out faster. 

Lower ACH values indicate better air tightness and an energy-efficient building. For example, achieving a score of 5 ACH is significantly better than a score of 12 or 19.

Low ACH (3 or less):

• Your home has excellent air-tightness
• Focus on other building efficiency measures:
  • Upgrade to a high-efficiency HVAC system
  • Improve insulation in the attic and walls
  • Consider energy-efficient windows if the current ones are old
• Ensure proper ventilation to maintain indoor air quality

High ACH (10 or more):

• Prioritize air sealing:
  • Seal gaps around windows, doors, and penetrations
  • Address leaks in the attic and basement/crawlspace
  • Consider professional air sealing services
• Reassess insulation needs after air sealing
• Consider other efficiency upgrades for your home or building (HVAC, windows, etc.)

8 Common Places for a Home Air Leak

Cody outlines 8 of the most common leak points in the average home

• AC Vents - It sounds ironic, but these are common leak points. As Cody explains, “There's about a ⅛” opening around every air conditioning vent”.
• AC Registers -  “Registers that are pulling in air, those areas commonly aren't really sealed off.”
• Recessed lighting - “Can lights are huge culprits for letting in hot air from the attic.” says Cody.
• Plumbing and electrical penetrations - Pay particular attention to outlets that share an exterior wall or a wall with an unconditioned space.
• Basement rim joists - Some homeowners may look into basement insulation.
• Windows and doors - Look for loose caulking or poor installations around the windows and doors in your home.
• Fireplace dampers - Check with fireplace companies to repair damaged dampers, especially in the wintertime.
• Ductwork in unconditioned spaces - Ducts can also be tested for airflow and pressure differences using duct leakage testing.

Make Sure Your Energy Audit Company is Certified!

Choose a certified professional for your blower door test. Here are some questions to guide your decision:

• Do you have certifications for conducting blower door tests?
• Can you provide references or photographs of previous projects?
• What are your methods for identifying and sealing air leaks?

Certification through the Building Performance Institute (BPI) is a recognized standard. 

To become certified for conducting blower door tests, professionals must pass both a written and a field exam. The BPI Infiltration and Duct Leakage Certification ensures that professionals are skilled in using diagnostic equipment and can accurately measure and interpret air leakage data. 

Frequently Asked Questions

1. How long does a blower door test take?
   1. The tests typically take about an hour. This includes setup, testing, and then interpreting the results. Most companies will also use infrared sensors to check for leaks while the test is running.
2. Do I need to prepare my home before the test?
   1. Make sure all your windows are closed, otherwise the installer should set everything else up when they install the blower door over your front door.
3. Can I perform a blower door test myself?
   1. Probably not, the systems are expensive and require specialized training to set up and run.
4. How often should I have a blower door test done?
   1. If you haven’t performed one on your current home, and want to invest in improving its efficiency, it’s a great diagnostic to run
5. Will the test damage my home in any way?
   1. Nope! The test doesn’t damage any part of the door or frame.

Conclusion

A blower door test is a crucial step in ensuring your home is energy-efficient, comfortable, and healthy. By understanding the process and benefits, you can make informed decisions about improving your home’s air tightness and overall performance. If you're considering a blower door test, ensure you work with a certified professional to achieve the best results for your home.

Benefits of a Blower Door Test

Conducting a blower door test can offer multiple benefits:

• Enhanced Comfort: By sealing air leaks, your home will maintain a more consistent indoor temperature.
• Energy Savings: Reduced air leakage means your HVAC system works less, lowering your energy bills.
• Improved Air Quality: Sealing leaks can prevent dust, allergens, and outdoor pollutants from entering your home.