What is the recommended sequence when upgrading building envelope for energy efficiency?

What is the recommended sequence when upgrading building envelope for energy efficiency?

• A. Both simultaneously
• B. Air sealing first, then insulation
• C. Insulation first, then air sealing
• D. Neither matters

Answer: (B)

Seal the air leaks first, then install insulation. Air sealing stops drafts and uncontrolled air movement, which are the main pathways through which heat is lost or gained. If you insulate before sealing, these leaks will bypass much of the insulation, dramatically reducing its effective performance and leaving you with drafts and higher energy bills. By closing gaps and cracks around doors, windows, penetrations, attic hatches, rim joists, and duct connections first, you create a tight envelope. Then adding insulation works as intended, because the conditioned air isn’t sneaking through gaps to render the insulation less effective. This sequence also helps with moisture control and long-term comfort, since you’re reducing new air infiltration and allowing the insulation to perform at its rated value.

Seal the air leaks first, then install insulation.

Air sealing stops drafts and uncontrolled air movement, which are the main pathways through which heat is lost or gained. If you insulate before sealing, these leaks will bypass much of the insulation, dramatically reducing its effective performance and leaving you with drafts and higher energy bills. By closing gaps and cracks around doors, windows, penetrations, attic hatches, rim joists, and duct connections first, you create a tight envelope. Then adding insulation works as intended, because the conditioned air isn’t sneaking through gaps to render the insulation less effective. This sequence also helps with moisture control and long-term comfort, since you’re reducing new air infiltration and allowing the insulation to perform at its rated value.