Envelope · July 27, 2022
Look up. The attic is still the plot.
Most of the house’s energy story is above the drywall. Bypass, battled insulation, and a hatch that leaks like a chimney — that is where the money goes.
5 minute read · Anchors Aweigh Energy
People remodel kitchens. They do not remodel attics. The attic does not care. Stack effect will pull conditioned air up through every can light, chase, and unsealed top plate and throw it into a space that is 140 degrees in August. Then the air conditioner will do it again.
What “look up” actually means
- Find the pressure boundary. It is usually the ceiling plane, not the roof deck, unless you have a sealed attic on purpose.
- Air-seal before you blow insulation. Insulation that sits over a leak is a filter, not a blanket.
- Treat the attic hatch like a door. Weatherstrip it. Insulate the lid. Latch it.
- Cans, bath fans, and soil stacks are the usual criminals. So is the open bay above the kitchen soffit.
Quality Insulation Installation (QII) on new construction exists because this work is easy to skip and hard to see later. On existing homes we use a blower door and infrared together so we are not guessing which stain on the batt is a leak and which is a story.
If you only do one thing after reading this, weatherstrip and insulate the attic access. It is the cheapest HERS-adjacent improvement in the building.