What is a building envelope test?
Your building envelope is the airtightness of your home. A building envelope test measures the amount of air leakage you have in and around your home, giving you the exact volume of air you are losing by the hour. This is valuable information homeowners and builders can use to make informed decisions about increasing energy efficiency.
A building envelope test consists of a physical inspection and blower door testing. For the physical inspection, your technician will look through your home, inside and out, checking for common areas of air leakage like window gaps, hallway drafts, and broken seals outside of your home. Your home is depressurized for the blower door test and paired with a calibrated pressure sensor to tell you the exact volume of air leaking out of your home.
Why do I need a building envelope test?
Your home leaks air every day. It does this in cold or hot weather and can lead to higher energy bills throughout the year. Over time, this can also put significant strain on your HVAC system, causing it to wear out sooner, and require a frequent need for repairs. These are just some of the many reasons why you need a building envelope test.
With excess leakage, you also leave yourself open to property damage resulting from moisture between your walls and outside contaminants. Unfortunately, homeowners never notice these signs until it’s too late and they need to make some significant repairs. With building envelope testing, you can isolate leaks in your home and identify problems before they get worse.
Although it’s normal for homes to leak some air, too much leakage will cause your home not to pass the energy efficiency standard of the PA Energy Code. You are required to pass a building envelope test if you are building a new home or are making major renovations.
How is building envelope testing conducted?
There are two parts to a building envelope test; a physical inspection and blower door testing. Both don’t require a lot of time to complete and are non-invasive, meaning you don’t have to worry about being put out of your home. It’s completely safe to remain in your home during a blower door test.
During the physical inspection, your inspector will walk through your home and tour the outside of it. They will look for common areas of air leakage, checking the seams of your home’s interior and exterior, and evaluating the efficiency of your insulation. After the inspection, your technician will discuss options for improving your home’s building envelope and recommend the best ways you can go about doing so.
For a blower door test, your inspector will begin by sealing off your home. They will close all the windows and doors, also making sure to turn off your HVAC system and any system for ventilating your home. Then, a non-invasive frame is installed to your central door, where a large fan is attached. The purpose of the fan is to blow air outside of your home, depressurizing it and drawing air through the leaks.
Your technician will use a manometer, or pressure sensor, to measure the air volume of air entering your home. Depending on the size and complexity of your home, your test should take anywhere from one to two hours. Most of the time will be spent during the physical inspection and installing the fan. Blower door testing only takes about 15 minutes to complete.
How to pass a building envelope test
The best way to pass a building envelope test is with the help of a licensed inspector. They can pinpoint areas of your home that need significant improvements and make expert recommendations on how you can do it. But homeowners can do things on their own to help their homes pass a building envelope test and reach compliance with the PA Energy Code.
Southeastern Pennsylvania is in energy climate zone 4 according to the IECC (International Energy Conservation Code). In climate zone 4, a number of 3 air changes per hour is a passing score for a blower door test. However, Pennsylvania has increased the number of allowable air changes to 5 per hour.
Ways you can improve your building envelope:
● Seal cracks, gaps, and holes
● Check your windows and doorways
● Use high-quality sealants
● Don’t do temporary fixes
● Check your attic’s insulation
● Consult with your blower door test conductor
If you’re in the process of building a new home, the airtight drywall approach (ADA) can be used to create a continuous air barrier around your home and increase energy efficiency. During construction, two walls are built with spacing in the middle and are usually combined with simple caulk and seal (SCS) to fortify a new home’s envelope.