Building envelope is just another word for airtightness. You can measure the envelope through a blower door test conducted by fitting a large fan to the central door of a home and depressurizing it. Once the home is depressurized, a specially calibrated manometer measures how much air enters the home through leaks in your envelope.
Remember, it’s normal for a home to have some air leakage, but the amount of air leakage you are allowed to have will depend on your climate zone and building type. After your blower door test, your conductor will be able to advise you on changes you can make to improve your building envelope and increase energy efficiency.
It is vital that you hire a licensed inspector to conduct your test to ensure it’s done right. They have the expertise to advise you and make sure you’re on the path toward compliance. Contact your local Pennsylvania inspector here.
The table below shows the specific information of Pennsylvania envelope requirements at IECC climate zone 4. Philadelphia and Southeastern Pennsylvania is located in climate zone 4. Depending on the type of building you are contructing you may fall under the 2015 or the 2018 IECC energy conservation codes.
