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Reduction of Operational Carbon in Existing Buildings

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Research Team

Our Motivation:

"Regardless of how energy efficient new buildings might become, we will fail our mission towards global carbon neutrality, unless we offset the environmental side-effects of the dated buildings we operate today.

Our vision is to help transform dated buildings into sustainable and energy-autonomous living environments that

1) adapt to climate change dynamics

2) enhance occupant comfort.

Why sustainable?

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%. In the US, this translates to an increase of annual energy efficiency retrofits by 1500% for residential buildings alone. This is a major challenge, as we need to take into consideration each building’s unique set of operational characteristics, examples of which include (but are not limited to) building type, location, occupancy rate, and occupant lifestyle. Meanwhile, solutions must be simple to execute, affordable, and scalable.

Why energy autonomous?

Throughout my life, I have lived and worked in Greece and California, two places that are traditionally thought to be advantageous thanks to their “temperate” climate. While this was once true, over the past few years I have witnessed these “kind” climates suddenly turn into aggressive, inhospitable environments where blackouts due to extreme weather phenomena can last for over a week. This experience has shown me that localized energy autonomy is a critical component for the future of our infrastructure, even at places with the most favorable of climate conditions, such as temperate zones.  

From excessive heat waves to wildfires and unprecedented snowstorms, our climate is clearly changing at a rapid pace, yet our infrastructure has remained stagnant, often failing to protect us. The grid is no longer reliable as a single source of electricity, particularly under extreme weather phenomena. It is therefore critical that we begin the transition towards distributed energy models.

This makes me wonder how we might be able to harness the embodied energy of weather phenomena (such as wind, solar, and temperature differentials) and use it to transform dated buildings into self-sufficient microgrids that operate with on-site renewables.


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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.

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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. 

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). 

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.

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A multi-objective computational design framework that

  • Analyzes different energy efficiency intervention strategies
  • Proposes a series of actionable suggestions to minimize carbon emissions
  • Aims to maximize home electrification
  • Aims for energy autonomy
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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. 

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Cooperation Partner

Autodesk, USA
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Year 2022

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


Oct. 2022

Complete in-depth analysis and benchmarking of:

  1. Existing building decarbonization frameworks, and
  2. Commercially available data analytics and simulation tools.

Nov. 2022

Complete in-depth analysis and performance evaluation of buildings that have already undergone retrofitting interventions and draw relevant conclusions.


Jan. 2023

Consolidate interview insights from industry experts working on building decarbonization and home electrification.


Feb. 2023

Develop and validate a simulation/ analysis model that captures the operational characteristics of an existing building.


Apr. 2023

Develop design optimization methodology for energy-efficiency retrofits:

  1. Without on-site renewables.
  2. With on-site renewables.

Jan. 2024

Further develop methodology


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

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