Practice Exercise: Building Envelope Systems

Your Name

Test Scenario Base: Analyze Initial Building Model

After adjusting operating schedule and roof construction as requested:

  1. Operating Schedule to 12/5
  2. Roof Construction to R38

Test Scenario 1: Use Insight to Explore the Impact of Building Envelope-Related Design Decisions

As requested in the brief, the Insight Factor tiles were used to find a combination that will deliver the target Predicted Mean EUI of 54 kBtu/ft2/yr or lower. In order to achieve the lowest EUI, extreme measures were used, like 0% WWR and 2/3 window shading heights. These provide the best performance in order to achieve the target set, however I would not recommend these for my building design.

The following adjustments were made:

  • Building Oreintation adjusted by 90 degrees
  • WWR set to 0% in all 4 directions
  • 2/3 window shading height set in all 4 directions
  • Window Glass set to Trp LoE in all 4 directions
  • Wall construction set to 14-inch ICF

The predicted mean EUI of 49.1 kBtu/ft2/yr was achieved, thus successfully lowering the EUI past the target value:


However, using such extreme values would not be ideal, as having a WWR of 0% would lead to an undesirable design. Instead, the values will be adjusted to more reasonable and affordable values, and combined with power and lighting measures, along with solar measures in the future test scenarios.

Adjusted values:

  • Building Oreintation adjusted by 90 degrees
  • WWR set to 40% in the East and West direction
  • WWR left fully flexible in the North and South direction
  • 1/4 window shading height set in all 4 directions
  • Window Glass set to Trp LoE in the East and West direction
  • Window Glass set to Dbl LoE in the North and South direction
  • Wall construction set to R38 Wood, to match the roof construction

This has raised the EUI of the building to 55.8 kBtu/ft2/yr but with more desirable and affordable envelope features. This EUI can be lowered when combined with power & lighting measures + solar measures in scenario 2 and 3.


Test Scenario 2: Use Insight to Explore the Potential Impact of Power and Lighting Measures (versus Building Envelope Measures)

Instead of adjusting the building envelope, like in secenario 1, this time changes were made to the power and lighting measures:

  • Lighting efficiency was set at 0.3 W/sf
  • Daylighting and Occupancy Conrols was set to occupancy controls only
  • Plug load efficiency was set to 0.6 W/sf

The combination of these three measures (set to their extremes) has reduced the EUI from the original 60.9 kBtu/ft2/yr to 41.0 kBtu/ft2/yr


Combining these changes with the recommended envelope changes outlined in scenario 1, the following EUI is achieved:


Test Scenario 3: Use Insight to Explore the Benefits of Adding Photovoltaic Panels to Your Design

By adding photovoltaic panels to the design, one can singificantly reduce the EUI of the building. The following measures were added, in addition to the recommended ones outlined in scenario 1 and 2:

  • PV panel efficiency: 20.4%
  • PV payback limit: 20 years
  • PV surface coverage: 90%


As a result, my recommendations for this building would be to adjust the WWR and shading in the East and West direction, focus on efficient lighting and plug load systems, and finally maximize the potential that PV panels can provide.