**6. Conclusions**

Although existing assessment techniques have specific shortcomings, the number of research and initiatives currently undertaken in many countries highlight that the Life Cycle Assessment of buildings will be a feature of future assessments of building environmental impacts. Regulations incentivizing additional stakeholders to use these methodologies, as recommended by Eurima, should be the driving force behind increased acceptance of assessments of this type [7]. This adoption, on the other hand, requires studies that can deliver practical roadmaps, supporting the engaged stakeholders in establishing effective and long term business strategies. A more in depth understanding of the restrictions of LCA studies is a necessary requirement for developing reliable methodologies that can deliver high accuracy and reliability in a practical way.

When aggregated operational and embodied carbon are taken into account, total carbon curves have been formed identifying sweet spots where the embodied carbon investment cannot be recovered through operational savings. Data uncertainties, occupancy patterns, climatic conditions, building function and service life, source of energy, HVAC type and settings, and the type of insulation used, all contribute to the theoretical minimum. As a result, identical optimal specifications cannot be provided for various scenarios, rather, sufficient analytical and predictive understanding is required.

Considerable total energy savings can be achieved by practices and standards based on such principles. Such studies can help determine optimum insulation levels that can be incorporated into design of a building or that may be needed by standards in the future, as well as the limits to how much present energy-saving methodologies can be increased using certain technologies. Although whole life cycle thinking is now acknowledged in several codes and standards around the world, the lack of availability of reliable and accurate data, and the differences in adopting the existing methodologies for generating EPDs and other LCA results can lead to generating misleading messages to the manufacturers and policymakers. The study provides evidence in favour of better harmonisation and standardisation of LCA and LCI databases and procedures.

Due to high variation in the LCA results as a result of current discrepancies in modelling assumptions, applied methodologies, and data, the total carbon approach can be utilised as guideline for the time being, while the onus remains on LCA specialists and practitioners, as well as other key stakeholders, to harmonise the science across all industries, including software.

*An Aggregated Embodied and Operational Energy Approach DOI: http://dx.doi.org/10.5772/intechopen.103073*
