Where to put attics, knee walls, slopes, vaults, cheek walls, etc…

There seems to be some confusion among our Vermont users as to where all these components get modeled in OptiMiser. Here’s a quick primer:

Walls:

• The Walls page is used to model any wall above the foundation that forms a boundary between the conditioned space and the outdoors. Including:
  1. Main floor exterior walls
  2. Gable walls of conditioned attics
  3. Cheek/gable walls behind knee walls (but only if they are insulated)
• Be sure to hand calculate exterior wall area, when the building has finished attic space, lots of vaulted ceilings, or other unusual geometry
• When moving the thermal boundary behind a knee wall, use the second wall section to add the new cheek wall area on the improved side, while leaving the base area set to zero.

Attics:

• On the Attics page the Attic Areas are used to model any ceiling that forms a boundary between a conditioned space and an unconditioned buffer space such as an unconditioned attic. Including:
  1. The floor of standard full unconditioned attics
  2. The flattened peak of a conditioned attic
  3. The floor of the unconditioned space behind a knee wall (which forms the ceiling to the room below)
• When moving the thermal boundary behind a knee wall, use a separate attic section section to model the floor of that space and remove it by setting the improved area to zero.

Knee Walls:

• Knee walls are vertical boundaries between a conditioned space and an unconditioned buffer space that is also bounded by roof slope and the ceiling of the floor below.
• Knee walls are modeled using special Knee Wall sections on the Attic page.
• It is preferable to model a knee wall in association with the attic area that represents the floor of the space behind the knee wall.
• When moving the thermal boundary behind a knee wall, set improved area of that knee wall to zero.

Ceilings:

• The Ceilings page is used to model any ceiling that forms a boundary between a conditioned space and the outdoors (i.e. roofs). Including:
  1. Standard vaulted ceilings
  2. Roof slopes of a conditioned attic space
  3. Roof slopes of the space behind a knee wall (but only if insulated)
• When moving the thermal boundary behind a knee wall, use a separate Ceiling section section to add the newly insulated roof slope, leaving the base area set to zero.