Title: ASHRAE Net Zero Headquarters
Location of Proejct: Peachtree Corners, GA
Project Completion Date: November 2020
Firm Name: Houser Walker Architecture

Short Description: As a non-profit dedicated to advancing HVAC&R design and engineering, ASHRAE made a fundamental commitment to renovate an existing structure for its new headquarters, coupled with a mandate that the renovation be completed to Zero Energy standards, integrate advanced HVAC&R technologies, and provide high quality daylighting. The resulting design was completed in late 2020 for $200/sf, including full rehabilitation of the exterior envelope, interior renovation, and replacement of existing building systems. The final EUI modeled was 20.4, making it among the lowest EUI buildings over 50,000sf in the southeast. The building is tracking NZE certification in 2022.

Architect's Statement: ASHRAE is a global professional society advancing human well-being through sustainable technology for the built environment. The Society and its members focus on HVAC+R building systems, energy efficiency, indoor air quality, refrigeration and sustainability within the industry. ASHRAE has been headquartered in Atlanta since 2008, first occupying a structure near central Atlanta.

For their new headquarters, ASHRAE tasked the Design Team with creating a Net Zero Energy renovation of an existing 66,700 ft2 structure. Originally built in 1978, the building sits on 11 acres in the Technology Park area of Peachtree Corners, GA. Structurally, a cast in place concrete frame and slab carried a pre-cast concrete exterior panels and continuous storefront glazing. Functionally, two primary office blocks, each two floors high, and oriented to the east and west, are separated by a continuous atrium running north/south. Each of the main floors is approximately 26,000 gross square feet of office space, with a partial lower level containing building services and storage.
To achieve ASHRAE’s Net Zero Energy goals, the Design Team prioritized reducing the projected energy consumption (measured in units of Energy Use Intensity or EUI) while maximizing the flexibility and thermal comfort of the occupants. Beginning with a baseline projected consumption of 48 EUI for comparable office building, the final building has a projected EUI of 20.4, meaning that the building will consume less than ½ of the energy for a similar office space and making it among the lowest energy consuming office structures in the southeast.

To achieve these results, the design followed a rigorous process that addressed the right steps in the right order. In summary, the components to be developed were:
Identify and maximize passive design opportunities
Create a high performance envelope
Right size the building’s mechanical and electrical systems
Hone the building occupants comfort, daylight, and workplace design

We began by a comprehensive set of existing conditions metrics which prioritized the passive design elements of the building, as well as identifying the point of diminishing returns on items like insulation, window shading, daylighting, window to wall ratios, etc.

To maximize the performance of the building envelope, each component (openings, insulative capacity, daylight, overhangs, air infiltration) was optimized for the site, climate, orientation, and cost utilizing a proprietary analytics software. Schedule and budget required retaining the existing pre-cast exterior panels, which were overlaid with a 3.5” layer of continuous rigid insulation, stucco, and high performance window frames and glazing were installed. Custom perforated shading devices were optimized for each elevation. All potential areas of air infiltration were comprehensively identified, sealed, tested, and adjusted, resulting in an overall air-infiltration rate that is among the lowest achievable.

A key health consideration was providing high levels of productive daylight. Extensive analysis identified that 16 diffuse, high performance skylights, along with carefully calibrated exterior window locations, would providing near-continuous daylight to just under 60% of all occupied spaces. In particular, the Team found that window wall ratios calibrated for each orientation would provide the best daylight to thermal performance. Overall, the window to wall ratios average 28% for the east/west exposures and 37% for the north /south exposures.

Mechanical and electrical systems, including the lighting, were then ‘right sized’, minimizing their size and energy use. The building utilizes a fully hydronic heating/cooling overhead system coupled with a DOAS supply system. The hydronic system is the largest radiant panel HVAC installation known in the southeast and will stimulate further market acceptance, much as ASHRAE’s last headquarters design did for VRF technologies. Advanced lighting controls provide a high level of visual comfort and energy reduction and are minimized to take advantage of the generous daylight.

Creating a finely tuned “machine” allowed the Team to work closely with ASHRAE to develop a layout and workflow that greatly enhanced their productivity and interaction. By culture, ASHRAE’s staff engages in largely ‘heads down’, highly analytic work. A choice by the client to reuse existing high walled workstations pushed the Design Team to find areas of concentrated social interaction, achieved through a new outdoor deck, connections to a newly installed pondside walkway, and small moments at circulation crossroads on each floor. Vistas were maintained along each major corridor and interior materials were chosen for their ecological impacts and long term durability.

Finally, ASHRAE intended for the renovated facility to become a true “living laboratory”, a showcase for the latest HVAC&R equipment and technology, allowing all to view the building’s dashboard performance at all times. In addition, the National Renewable Energy Laboratory, a part of the U.S. Department of Energy, has selected the ASHRAE Headquarters building as their sole case study for 2021, producing a deep dive analysis and scrutiny of the building’s performance and promoting it to others looking to implement their own deep green renovations.

Final construction costs were $12,200,000 or approximately $183/sf of heated/enclosed space.