Insulation and Infiltration

Building Shell Air Barrier

Air Sealing All homes must pass a blower door test with a result between 0.50 ACHn and 0.25 ACHn 3

Good Building Envelope Create an airtight shell using wall sheathing and ceiling drywall. Fill cavities completely with insulation. Encapsulate insulation on all sides. Use required Energy Code R-values. 4 Correct 4

Attic Kneewalls

Air Sealing Incorrect Bottom plate must be sealed to poured wall, slab, or subfloor. 9 Correct

Air Sealing Soffits must be sealed at cantilevered floors. 10

Air Sealing Exhaust fan penetrations must be sealed at the band joist. Correct 11

Air Sealing Joist cavities under attic kneewalls must be blocked. 12 Correct

Air Sealing Penetrations through insulated floors must be sealed. 13 Correct

Air Sealing HVAC boots in insulated floors must be sealed to the subfloor. 14 Correct

Air Sealing Top and bottom plate penetrations must be sealed. Correct 15 Correct

Air Sealing Exterior doors must have weatherstripping, thresholds, and doorknobs prior to final inspection in order to pass (including basement doors if they penetrate the building envelope). 16 Correct

Air Sealing Gaps between pieces of exterior sheathing must be sealed. Incorrect Correct 17

Air Sealing Penetrations in exterior wall sheathing must be sealed. Correct Correct 18

Air Sealing Exterior walls of fireplace chase must be sealed (including combustion air inlet). Incorrect 19

Air Sealing Shower and tub drains must be sealed (rock wool/fiberglass not acceptable). Incorrect Correct 20

Air Sealing Solid sheet must be installed behind tubs and showers on insulated walls. 21 Correct

Air Sealing Window and door rough openings must be sealed (not chinked with insulation). 22 Correct

Air Sealing Stud cavities at changes in ceiling height must be blocked. 23 Correct

Air Sealing Attic kneewall doors must seal tight- this requires weatherstripping and a latch. 24 Correct

Air Sealing Stud cavities blocked from attic – including attic kneewalls 25 Correct

Air Sealing Attic kneewalls must be sheathed (and R-19 minimum insulation value). 26 Correct

Air Sealing Chase caps and penetrations through chase caps must be sealed 27 Correct

Air Sealing Chases must be capped. Correct Incorrect 28

Air Sealing Recessed can lights in insulated ceilings must be air tight. Correct 29

Air Sealing Ceiling mounted electrical fixtures, including lights, ceiling fans, and speakers in insulated ceilings must be sealed to drywall. Incorrect 30

Air Sealing HVAC boots in insulated ceilings must be sealed to drywall. 31 Correct

Air Sealing Attic scuttle holes must seal tight- this requires weatherstripping 32 Incorrect

Air Sealing Attic pulldown stairs located in conditioned space must seal tight. Correct Correct 33

Insulation Basement foundation walls must be insulated to a minimum of R-5 if they are part of the building envelope. To be considered a basement wall, the average gross wall area (including openings) must be at least 50% below grade. Each wall must be considered separately. 34 34

Insulation Concrete foundation walls may not be insulated with kraft-paper faced fiberglass batts. Unfaced batts, blown in fiberglass, or perforated vinyl encapsulated batts are permitted. Note: Floors over an unconditioned basement can be insulated instead of foundation walls. When intending for the basement to be conditioned, you must plan for this in the load calculation or the equipment will be too small. 35

Insulation Insulation must be installed against a solid air barrier (OSB, drywall, concrete, or solid sheet good). Incorrect 36

Insulation Wall insulation must fill cavities completely. 37 Correct

Insulation Attic kneewalls must be a minimum R-19 insulation value 38 Correct

Insulation All areas of the attic must have vent openings. Bonus rooms over the garage must be vented, in addition to the attic. 39 Correct

Insulation Blown attic insulation may not block soffit vents - baffles must be used Incorrect 40 Correct

Insulation Blown attic insulation must have rulers and an attic card in each accessible attic space 41 Correct

Moisture and Indoor Air Quality No polyethylene is allowed in above or below grade wall assemblies (except behind tubs and showers in bathrooms) 42

Moisture and Indoor Air Quality All fireplaces and other combustion equipment must be equipped with a flue and outside combustion air supply. No ventless fireplaces are allowed. 43 Correct

Insulation Limit the number of 4x8 sheets of subfloor installed in the attic. (If more than two sheets of subfloor is desired, it is recommended they be raised up to provide for the full attic height of insulation underneath.) 44

Building Shell Air Barrier

Air That Has Been Heated, Rises. As the air inside the envelope is heated, it begins to rise.

Air That Has Been Heated, Rises. The Air will escape through any available hole.

Air That Has Been Heated, Rises. COMMON HOLES Bathroom Fans and Wiring/Plumbing penetrations

Air That Has Been Heated, Rises. As air leaves the envelope, it creates a Negative (pulling) pressure.

Air That Has Been Heated, Rises. Outside air is drawn into the home to replace the escaping warm air.

Air That Has Been Heated, Rises. The cold outside air is then heated. As the air is heated it rises.

Air That Has Been Heated, Rises. The cycle is repeated.