🧧 Ready your envelope – Part 2

Ready your envelope – Part 1 is an overview of the role of a tight building envelope.

“A house needs to breathe” is a cliche in the world of contracting that is just … false.

Why it matters: This is a way to describe a leaky house and a leaky house cannot maintain the cold or heat in your house like a tight house can.

⛏️ Dig deeper with Dr. Allison Bailes excellent book on this topic.

🥊 The bottom line: Your house first needs to be as air tight as possible, and then it needs adequate insulation.

🔭 Zoom out: The shell (envelope) of your living space is made of 6 sides —> the floor, the ceiling and 4 walls.

  • The envelope is doing its job IF it resists the forces of nature.

⚙️ How it works: Let’s remember 3 laws from high school physics.

👉 Hot moves to cold

👉 Wet moves to dry

👉 High pressure moves to low pressure

🔬 Zoom in: Today, think about hot moving to cold.

  • Replace the phrase “hot air rises” with “hot air moves to cold air”
  • Example: Hot air in your attic is moving DOWN toward the cold air in your house
  • Wherever your ceiling plane is NOT air sealed —> like around can lights

✅ For your Smart Homeowner list

  • If you can’t adequately control the comfort in your home, the solution does not start with getting a new AC.
  • Air seal first.
  • Insulate second.
  • Address HVAC third.



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