HEWITT used Sefaira to analyse and assess the energy performance of three concepts for a high-rise residential development in Seattle with LEED certification goals. Sefaira’s Real-Time Analysis Plugin for Revit helped them assess the energy performance and feasibility of each proposed design concept within a short time span: two weeks from concept design to presentation. They also used Sefaira’s Daylighting Visualization tool to drill down into the daylighting performance of their preferred design option.
- Project type: High-rise residential
- Location: Seattle, WA
- Building type / program: Multifamily
- Floor area / stories / occupancy: 84,873 sq ft/ 24 Stories / 180 Units
- Project stage & completion date: Concept design
- Performance Baseline: 2012 Washington State Energy Code
- Performance Goal: LEED certification & Built Green
- Sefaira software used: Real-Time Energy and Daylighting analysis in Revit
Hewitt is designing a 180-unit residential tower over 24 stories on a prominent corner plot in Seattle, Washington. The design team chose to integrate performance analysis from the start of the project for a few reasons; Firstly, the project needed to meet the baseline Washington State’s 2012 energy code, but beyond that, the client wanted to achieve LEED accreditation. This would raise the performance of the property above the local baseline and consequently improve its marketability. Secondly, the design team wanted to demonstrate to the client that they were thinking critically about site-appropriate building forms that would yield the most value for the owners and future occupiers.
How Did They Do it?
Schematic whitebox models of the different concepts and proposed floor plans
To accomplish both goals, HEWITT used Sefaira to implement a performance-based approach to design. For them, this meant testing three options to determine whether each design was contextually appropriate, which design added the most real-estate value, and which design performed best in terms of energy and daylighting.
Option one’s “efficient form” has a simple rectilinear plan that meets the city’s minimum space standards. The “space-add” option introduces an enclosable garden room on top of the minimum space standards, whilst sections of the “glorious view” option stretch and pull from the core massing to capture key views across the city.
In the “Space-Add” option, the 110sqft garden rooms would be useable in different seasons throughout the year, making it the most favoured design option. To the team’s delight, Sefaira analysis showed that the option performed 3% better than the other designs.
Rendering of the three design options, indicating floor area and percentage to Net Zero Energy. In the space add option, HEWITT calculated total floor area and percentage to Net Zero Energy with and without the garden room.
Using Sefaira’s daylighting analysis tool, they also discovered that the garden rooms reduced the floor area exposed to unfavourable solar heat gains by 30%, while retaining full use of the space.
Indicative floor plan and daylight rendering for “Space-Add” option. The daylighting visualisation of the floor plan without a garden room (L). The visualisation with a garden room (R) shows the potential solar heat gain savings.
By using Sefaira, the HEWITT team were able to show that in addition to the extra 110 square feet of usable floor space per unit, they would be able to achieve a 3% increase in energy efficiency and a 30% reduction in detrimental solar heat gain, if they selected their preferred design option.
Project designer Rene Fresquez said, “We wanted a tool to measure, test and substantiate our design choices. Using Sefaira during concept design allows us to make informed decisions to enhance value and reduce post-design alterations to the building form. Sefaira helped us to generate an impactful visualisation to clearly illustrate and compare each concept’s value.”
Fresquez also said that being able to clearly communicate the potential cost savings in simple terms added tremendous value to their client presentations. He added that the client was able to realize the benefits of selecting a high-performance building before considerable time and expense is spent on developing a concept that may later require alterations to improve its performance.
With analysis results in hand, they could select the better performing design, optimise it to meet and exceed the design requirements – including minimum space, and energy and daylight performance – and confidently move the selected concept ahead.
HEWITT is an integrated practice of architects, landscape architects and urban designers with a passion for places that connect people. Since their founding in 1975, they have worked with clients to create places that elevate the urban environment and enrich the everyday life of citizens. The firm is grounded in a collaborative and integrated design approach that is fundamental to the way we practice.