The outer walls, attic and basement floor are the “envelope” of most homes. They are the places where money can literally fly out of your home.

During winter, if the envelope isn’t properly sealed, warm air will escape from the attic as shown by the red arrows on this diagram. This creates a “convection or stack effect”, pulling cold outside air into the home through your basement or windows, outer doors, exterior cracks and vents. When it happens, you’ll feel drafts. And, oftentimes, you’ll be breathing polluted air sucked up from the basement. The process is reversed during summer, with warm air coming in and conditioned air escaping.

While these air escape and entry routes aren’t immediately obvious they add up to large energy losses that cost you thousands of dollars.

During the audit, we’ll thoroughly inspect for air leaks, focusing on nine common areas where most problems originate. (Click on Letters A-I for more detail)


Common Household Air Leaks


  1. A Behind Kneewalls
  2. B Attic Hatch
  3. C Wiring Holes
  4. D Plumbing Vent
    Plumbing vents supply air for the escape of noxious fumes and equalize pressure within plumbing systems. If the holes cut to fit the vent pipes are not caulked and sealed, they also allow costly warmed or cooled air to escape.
  5. E Open Soffit (the box that hides recessed lights)
    The underside of a building overhang, beam, or arch, especially the underside of a stair or roof overhang is called a soffit. They are often covered by insulation which hides cracks, gaps and holes.
  6. F Recessed Light
    Recessed lights in a one-story house or in the ceiling of a second-story create open holes into your attic that allow unwanted heat flow between conditioned and unconditioned spaces. During cold New Jersey winters, escaping heat onto a snow covered roof can cause ice damns. Improperly sealed recessed lights in bathrooms allow moisture to escape, often resulting in moldy or rotted attic rafters or floor joists.
  7. G Furnace Flue or Duct Chaseways (the hollow box or wall feature that hides ducts)
    The opening around a furnace or water heater flue or chimney can be a major source of warm air moving in the attic. Because the pipe gets hot, building codes usually require 1 inch of clearance from metal flues (2 inches from masonry chimneys) to any combustible material, including insulation. But these gaps CAN be sealed with lightweight aluminum flashing and special high-temperature (heat-resistant) caulk.
  8. H Basement Rim Joists (where the foundation meets the wood framing)
    In the basement, the above floor joists end at the rim joist creating multiple cavities along the length of the wall, and many opportunities for leakage.
  9. I Windows and Doors
    Heat loss and gain occur by infiltration through cracks in window and door assembly.