Designing Retrofits for Energy-Efficient Apartments
Syracuse University faculty in the School of Architecture and the College of Engineering & Computer Science led a multidisciplinary team to demonstrate a transformative approach to whole-building energy efficiency retrofits in cold climates — funded by the U.S. Department of Energy. The result: two fully retrofitted student apartment buildings on SU’s South Campus, delivering dramatic reductions in energy use, improved indoor air quality, and fast installation.
Project Overview
The Lambreth Lane retrofit — completed in summer 2024 at 221 and 231 Lambreth Lane on SU’s South Campus — is a nationally significant demonstration of Advanced Building Construction (ABC) technologies applied to existing multi-family housing. Two eight-unit student apartment buildings were retrofitted using an innovative whole-building approach that integrates prefabricated exterior insulated panels with high-efficiency mechanical systems. Post-retrofit monitoring confirms 75% reductions in thermal energy use, over 30% improvements in indoor air quality, and full installation across both buildings in just 2.5 months.
Technical Approach
The retrofit solution integrates three core components: a 3D scan-to-modeling workflow for retrofit configuration, prefabricated exterior insulated panels, and high-efficiency mechanical pods for heating, cooling, ventilation, and domestic hot water. Crucially, these systems are designed as a holistic system: envelope and mechanical upgrades are sized and specified to work together.
The exterior-focused approach minimizes on-site time and resident disruption at every phase: pre-retrofit assessment, installation, and ongoing maintenance. The 3D scanning workflow quickly and accurately captures existing building geometry; the prefabricated panels arrive ready for fast installation and deliver insulation five times better than the original wall assembly; and the mechanical pods arrive pre-configured, sized to match the envelope’s reduced loads, and designed for exterior access during maintenance. Together, these systems reduce the energy needed for heating and cooling while meaningfully improving the comfort and health of residents.
Key Retrofit Systems
Hover over the highlighted retrofit systems to learn how each component contributes to energy performance, comfort, and healthier indoor conditions.
Panels
Exterior prefabricated insulated panels improve air-sealing, increase thermal performance, and provide better acoustic insulation.
- 1Prefabricated lightweight modules
- 2Insulated R-32 total wall assembly
- 3Exterior air- and water barrier
Mechanical Pods
High-efficiency mechanical pods provide heating, air conditioning, energy recovery ventilation, and hot water systems.
- 1All-in-one factory-assembled units
- 2Energy recovery ventilation
- 3Ground-level maintenance access
Roof
New roof insulation reduces energy loss and helps stabilize indoor temperatures during cold and warm seasons.
- 1Insulated R-25 roof assembly
- 2Air + vapor barrier EPDM membrane
- 3Dark surface suitable for cold climates
Windows and Doors
High-performance glass doors and windows reduce drafts, improve comfort, and help control solar heat gain.
- 1Triple-pane glass
- 2uPVC frames with warm-edge spacers
- 3Operable windows and rear doors
Mechanical Chase
Exterior distribution systems support heating, cooling, and fresh air delivery while limiting disruption inside apartments.
- 1Exterior heating + cooling distribution
- 2Accessible for maintenance
- 3Durable steel-framed protection
Highlighted building section showing where the major retrofit systems are located. Hover over the orange markers to view each system’s role, key features, and performance contribution.
Installation
The project demonstrates how innovative whole-building retrofit solutions can reduce construction timelines, costs, and disruption to residents while delivering superior energy performance and comfort. Retrofit components were delivered and installed on two buildings in under three months through an integrated systems approach.
Interactive chart comparing the Lambreth Lane retrofit timeline with similar retrofit projects. Use the tabs to compare total construction months, days per unit, and days per 1,000 square feet.
Energy Savings
Post-retrofit monitoring confirms a 75% reduction in thermal energy use during the heating season. Analysis of energy use relative to outdoor temperature shows that greater temperature differentials between indoors and outdoors yield proportionally greater savings, indicating that the building envelope is performing as designed.
Normalized thermal energy use, pre- and post-retrofit, showing 75% reduction
75% Reduction in Thermal Energy Use
* Normalized by heating degree days (HDD) to account for weather variation between pre- and post-retrofit periods.
Normalized thermal energy use and outdoor temperature variation analysis before and after the retrofit.
The savings come from across the integrated system: the insulated wall and foundation panels account for 38% of the total reduction, windows, doors, and air-sealing contribute 22%, and the mechanical pods an additional 37%, as shown in the figure below. The envelope and the mechanical systems are designed to work together, all contributing meaningfully to the thermal energy savings.
Completed retrofit exterior showing upgraded doors and windows, new insulated exterior panels, and exterior mechanical systems.
Resident Impacts
This DOE research study measured changes in energy use, indoor air quality, and comfort conditions before and after the retrofit. Sensors installed on the interior and exterior of both buildings collected data on temperature, humidity, air quality, and energy consumption over the full monitoring period.
Student residents contributed by living in the monitored units before and after the retrofit and completing surveys on comfort, air quality, and building appearance.
Results show substantial improvements across all measured categories. Indoor temperatures are more stable year-round, active cooling is now available in warmer months, and continuous mechanical ventilation provides fresh air throughout the year.
responses
Resident Experience: Comfort, Air Quality, and Noise
Comfort
Residents gain better control over indoor temperature through wall thermostats, ceiling-mounted fan coil units, and improved thermal wall insulation.
- 1More stable indoor temperatures
- 2Cooling available during warmer months
- 3Improved comfort near exterior walls
Air Quality
Fresh air delivery and mechanical ventilation support healthier indoor conditions, especially when residents gather in shared living spaces.
- 1Continuous fresh air delivery
- 2Energy recovery ventilation
- 3Improved indoor environmental quality
Noise Reduction
Thicker insulated exterior wall assemblies help reduce outdoor noise transfer, supporting quieter interior spaces.
- 1Reduced exterior noise transmission
- 2Improved acoustic comfort
- 3More comfortable bedrooms near exterior walls
Air Quality
Fresh air delivery and mechanical ventilation support healthier indoor conditions, especially when residents gather in shared living spaces.
- 1Continuous fresh air delivery
- 2Energy recovery ventilation
- 3Improved indoor environmental quality
Interactive resident impact drawing showing how the retrofit supports comfort, fresh air, and noise reduction inside the apartments. Hover over the orange markers to view each impact area.
Acknowledgements
The project “Integrated Whole-Building Energy Efficiency Retrofit Solution for Residences in Cold/Very Cold Climates” Award Number DE-EE0009060 was funded by the Building Technologies Office, Office of Energy Efficiency and Renewable Energy at the U.S. Department of Energy (DOE) under the Advanced Building Construction with Energy Efficient Technologies and Practices (ABC) initiative, with additional support from the New York State Energy Research and Development Authority (NYSERDA).
Collaborating Partners:
TKFabricate, Taitem Engineering, Cycle Architecture and Planning, Signetron, VIP Structures, Yantch Plaster and Stucco Systems
Faculty & SyracuseCoE Team:
Bess Krietemeyer (Principal Investigator), Jianshun (“Jensen”) Zhang (Co-PI), Nina Wilson (Co-PI), Bing Dong (Co-PI), Tammy Rosanio (Co-Investigator)
Graduate Research Assistants:
Emily Lane, Shayan Mirzabeigi, Jacqueline Motsiff, Jialei Shen, Sameeraa Soltanian-Zadeh, Rui Zhang
Undergraduate Research Assistants:
Austin Chang, Cindy Gao, Alexandra Gordon, Grace Hannah, Brandon Henderson, Brandon Isabell, Caleb John, Cole Kaneshiro, Arlo Kemmerer-Scovner, Danny Nguyen, Aung Htet Khant Paing, Yifan Shen, Ryan Swank, Ayden Theroux, Ran Wang
Contact Information:
Bess Krietemeyer, PhD
Associate Professor
School of Architecture
Syracuse University
eakriete@syr.edu