Reducing the amount of air that leaks in and out of your home is a cost-effective way to cut heating and cooling costs, improve durability, increase comfort, and create a healthier indoor environment.
You may already know where some air leakage occurs in your home, such as an under-the-door draft, but you’ll need to find the less obvious gaps to properly air seal your home.
For a thorough and accurate measurement of air leakage in your home, hire a qualified technician to conduct an energy audit, particularly a blower door test. A blower door test, which depressurizes a home, can reveal the location of many leaks. A complete energy assessment will also help determine areas in your home that need more insulation.
Before you begin the air sealing process, let’s talk about air leakage and how to measure the air leakage in a home through blower door testing.
Air leakage occurs when outside air enters and conditioned air leaves your house uncontrollably through cracks and openings. It is unwise to rely on air leakage for ventilation. During cold or windy weather, too much air may enter the house. When it’s warmer and less windy, not enough air may enter, which can result in poor indoor air quality. Air leakage also contributes to moisture problems that can affect occupants’ health and the structure’s durability. An added benefit is that sealing cracks and openings reduces drafts and cold spots, improving comfort.
AIR LEAKAGE AND CODE
A typical existing home can be very leaky by today’s standards. The metric used to measure the leakiness of a home is air changes per hour (ACH), often measured at 50 Pascal’s (ACH50). In many existing homes this number can approach or even exceed 10 ACH50. For context, the International Energy Conservation Code (IECC), which sets minimum standards with regards to energy efficient construction, requires all new construction to meet certain air leakage requirements. In the the 2015 edition, it was 3 ACH50 (air changes per hour @ 50 pascals). It is widely accepted throughout the industry that anything less than 5 ACH50 is considered to be a tight home.
BENEFITS OF IMPROVING AIRTIGHTNESS
The benefits of having an energy efficiency home with little air leakage are great. Here are some advantages:
- Lower utility bills – reduction of loss of conditioned air and heating/cooling loads
- Improved comfort typically decreasing unwanted draughts & allergens
- Improved indoor air quality – decrease allergens, dust, and dirt
- Reduce/eliminate moisture problems.
- Better sound barrier to outdoor noise
- Reduced environmental impact – lose less energy through the building envelope.
CONDUCTING A BLOWER DOOR TEST
Home Energy Heroes can measure actual air infiltration with the use of blower door equipment. If the first test at lock-up is poor, we can identify leakage areas for the builder or homeowner to remediate so that upon completion, the final airtightness test should deliver a low air-leakage home. And you will then know you won’t be in the camp of seeing 30% of your heating/cooling running costs escaping from your home.
To measure a home’s air leakage, we use a tool known as a blower door. To conduct a blower door test, a fan is mounted into a frame of an exterior door, which pulls air out of the house thus lowering the air pressure inside. Because the outdoor air pressure is now higher than the air pressure inside the home, the outdoor air is pulled in through all penetrations, crack and openings in the buildings envelope.
To measure the airflow, a manometer is connected to the fan and includes reference hoses inside and outside of the home that monitor airflow and pressure. The manometer measures airflow at cubic feet per minute reading (CFM) measured at 50 Pascal’s. Using this number and the volume of the home, we can calculate the infiltration or leakage rate.
Formula for calculating the ACH on a house using a blower door:
ACH50 = CFM50 x 60 ÷ House volume
SCHEDULE YOUR BLOWER DOOR TEST
If you are a builder or homeowner and are interested in getting a blower door test done on your home, please contact us at 518-377-9410 or firstname.lastname@example.org.