Skip to main content Skip to secondary navigation

Reduction of operational carbon in existing buildings through energy efficiency

Main content start

Research Team

Our Motivation:

By 2050, every building in the world should be carbon neutral. Yet, today’s buildings consume 1/3 of global energy and will continue to do so in the coming decades unless strategic action is taken. Therefore, to meet our energy targets by 2050, we need to minimize the operational carbon in existing buildings by at least 60% [1]. In the US, this translates to an increase of annual energy efficiency retrofits by 1500% for residential buildings alone [2]. This is a major challenge, as we need to take into consideration each building’s unique set of operational characteristics. Meanwhile, solutions must be simple to execute, affordable, and scalable.


Icon Contribution

Research Contribution

A robust analysis framework is needed that will enable us to quickly and easily evaluate the potential of an existing building to become an energy efficient and/ or energy autonomous living environment through the use of well-established and innovative technologies.

Icon Problem


Practical Problem

About 42% of a building’s energy use stems from its heating and cooling loads, and a significant percentage of these loads is determined by the energy loss that occurs through the building envelope. Therefore, a lot of attention has been given towards improving building envelope thermal performance. Yet, both conventional and innovative strategies lead to similar energy savings, with the best-case scenario being a 50% reduction in energy consumption [4].

Because of this, to achieve carbon neutrality in existing buildings, we need to shift our attention towards investigating technologies that promote on-site renewable energy generation (e.g. solar panels/ wind energy) and home electrification (e.g. heat pumps/ thermoelectric generators) [5] [3].

Conceptual Problem

Transitioning from intensive building envelope upgrades that aim to maximize energy savings through improved thermal performance to the adoption of moderate envelope interventions in conjunction with electrification strategies and on-site renewables in the context of residential retrofits.

Icon Solution


A multi-objective computational design framework that 1) analyzes different energy efficiency intervention strategies, 2) proposes a series of actionable suggestions to minimize carbon emissions, 3) aims to maximize home electrification, and 4) aims for energy autonomy.

Icon added value

Added Value For The Industry

The developed framework will help AEC professionals make faster and more informed decisions in the context of residential energy efficiency retrofits.

Additionally, the framework will consider the implementation of mature as well as more innovative on-site energy harvesting technologies that could prove to be efficient and scalable solutions in the context of retrofitting in the near future.

Finally, insights from the developed framework could be integrated into existing design toolkits.

Icon Cooperation partner

Cooperation Partner

Autodesk Logo
Autodesk, USA


Icon Timeline





Spring 2022

Research became awarded: "Framework for Operational Carbon Reduction in Existing Buildings”.



Oct - Dec

  •  Research on energy efficiency measures for single-family homes.
  • In-depth analysis of the energy balance equation for operational carbon (net-zero energy buildings).
  • Benchmarking of Microsoft Excel-based energy modeling tools for the design of net-zero single family homes (course project).
  • Application of Life Cycle Assessment methodologies in the built environment context (w/ case study as part of a course).


Jan - Mar

  • Research on environmental performance targets for new and existing buildings for the decades leading up to 2050.
  • Benchmarking of the energy modeling tool EnergyPlus (EnergyPlus with Open Studio and SketchUp).
  • Literature review and in-depth analysis of net-zero building definitions.
  • Research on the implementation of whole life cycle assessment case studies at the building level in the AEC industry.


Mar - Jun

  • In-depth exploration and benchmarking of the Autodesk Spacemaker software.
  • Literature review on whole life cycle assessment methodologies and tools.
  • Procurement of building energy consumption data for a full 12-month period for a multi-family apartment complex - potentially to be used as a baseline model for the future case study.
  • Procurement of building design data for a single-family home - potentially to be used as a baseline model for the future case study.
  • Benchmarking of energy model calibration strategies and trade-offs.
  • In-depth exploration and benchmarking of the Autodesk Insight energy modeling tool.


Jul - Aug

  • Benchmarking and in-depth analysis of whole life cycle assessment tools.
  • Build prototypes for an automated whole life cycle assessment tool to enable iterative, data-driven early-stage design. 
  • Conduct user testing on the prototypes.



  • Case study design for the automated whole life cycle assessment tool.
  • Validation of the proposed methodology/ tool.
  • Write and publish the results of the case study.


If you want to participate in the project please reach out to Eleni Alexandraki.


  1. “Net Zero Carbon Buildings Three Steps to Take Now.” Arup,….
  2. Nadel, Steven, and Adam Hinge. Mandatory Building Performance Standards: A Key Policy for Achieving Climate Goals. 22 June 2020,….
  3. Chandel, Rahul, et al. “Prospects of Sustainable Photovoltaic Powered Thermoelectric Cooling in Zero Energy Buildings: A Review.” International Journal of Energy Research, 2022,
  4. Kamel, Ehsan, and Ali M. Memari. “Residential Building Envelope Energy Retrofit Methods, Simulation Tools, and Example Projects: A Review of the Literature.” Buildings, vol. 12, no. 7, 2022, p. 954.,
  5. Walker,   I.   S.,   Less,   B.   D.,Casquero-Modrego,   N.(2022). Pathways to   HomeDecarbonization in the US. Proceedings of the 2022 Summer Study on Energy Efficiency in Buildings.American Council for an Energy Efficient Economy (ACEEE), 21-26 August, Pacific Grove, CA