What’s the Difference Between Energy and Heat Recovery Ventilators?

On the Mastering Building Science discussion board, Allison A. Bailes III, PhD asks students: What is the difference between an ERV and an HRV?
Allison A. Bailes III, PhD: In the homework, I asked, “What is the difference between an energy recovery ventilator (ERV) and a heat recovery ventilator (HRV)?” Let’s address that here and extend […]

Air, Thermal, Vapor & Water Control Layers in Wall Assembly

On the Mastering Building Science discussion board…
Allison A. Bailes III, Ph.D. answers student questions about air, thermal, vapor and water control layers in wall assembly.

Student 1: 
I’m going to repeat what’s been said about the control layers in my own words, and ask a few questions for clarity:

There’s rain control, air control, vapor control, and thermal control. […]