Dynamic Versus Static Life Cycle Assessment of Energy Renovation for Residential Buildings
Round 1
Reviewer 1 Report
Please find attached.
Comments for author File: 
Comments.pdf
Author Response
Please find the answers to the review comments and the revised paper with track changes in attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
- Major issues
Point 1. TITLE
The title could be substantially improved, as it is very generic. In my opinion, the reader's attention is not well captured until he/she has read the abstract. We propose three examples of titles that would significantly improve the reader's attention by revealing part of what will be found in the specific case study.
- A Framework for Dynamic Life Cycle Assessment: A Case Study of Renovation of a Residential Building.
- Development and Application of Dynamic Life Cycle Assessment Framework for Recommendation of Renovations of Residential Houses.
- Dynamic Life Cycle Assessment of Renovating Buildings: A Framework for the Analysis of Environmental Impacts.
Point 2. ABSTRACT
The abstract is well structured and correctly explains all the research. However, when the authors talk about the "renovation" of buildings, the result can be very ambiguous for some readers. To avoid a non-expert being forced to deduce it, they should clarify what kind of renovation they are referring to (air renovation, ventilation renovation, energy renovation,...).
Point 3. INTRODUCTION
Although the references used are pretty up to date, there is a disproportion between papers that do not belong to research published in journals. Although the references are quite up to date, there is an abuse of resorting to titles of sites, conference papers, or books to the detriment of JCR publications, which is where this research should mostly be inserted in the context of other similar studies. Therefore, there is a significant lack of references to essential articles to support and justify this research. For example, this reviewer suggests five references that could be included (among others) with recent analyses that perform life cycle analysis (environmental or even of the three dimensions of sustainability) carried out with great rigor in high-impact journals or review articles in this own journal. Note that the format and style of the references is the correct one indicated in the Authors' Guide.
- Balasbaneh, A.T.; Marsono, A.K.B. Applying multi-criteria decision-making on alternatives for earth-retaining walls: LCA, LCC, and S-LCA. J. Life. Cycle Assess. 2020, 25, 2140–2153. doi: 10.1007/s11367-020-01825-6
- Sánchez-Garrido, A.J.; Navarro,J.; Yepes, V. Multi-criteria decision- making applied to the sustainability of building structures bases on Modern Methods of Construction. J. Cleaner Prod. 2022, 330, 129724. doi: 10.1016/j.jclepro.2021.129724
- Seol, Y.; Lee, S.; Lee, J.-Y.; Han, J.-G.; Hong, G. Excavation Method Determination of Earth-Retaining Wall for Sustainable Environment and Economy: Life Cycle Assessment Based on Construction Cases in Korea. Sustainability2021, 13, 2974. doi: 3390/su13052974
- Janjua, S.Y.; Sarker, P.K.; Biswas, W.K.; Sustainability implications of service life on residential buildings – An application of life cycle sustainability assessment framework, Sustainability Indic. 2021, 10, 100109. doi: 10.1016/j.indic.2021.100109
- Wulf, C.; Werker, J.; Ball, C.; Zapp, P.; Kuckshinrichs, W. Review of Sustainability Assessment Approaches Based on Life Cycles. Sustainability2019, 11, 5717. doi: 3390/su11205717
Point 4. METHODOLOGY
- Depending on their expected life cycle performance, the different scenarios will incur future costs at different times. For these impacts to be comparable, future costs should be discounted and converted to present values (2022). It would seem reasonable that the monetary value of the environmental impact indicators should integrate discount rates, especially since the article's objective is to perform dynamic temporal analysis of the life cycle.
- According to ISO 14040, life cycle assessment should be carried out in four phases: definition of the objective and scope, inventory analysis, impact assessment, and interpretation of the results. The article would gain clarity if the methodology were structured according to equivalent subsections, going from the general to the particular. It must make the functional unit clear since it is currently difficult to find it in a large amount of text.
- In this type of analysis, a figure that summarizes the system boundaries considered in the evaluation would be instrumental (not to be confused with the phases shown in figure 1).
Point 5. RESULTS AND DISCUSSION
The research must include a SENSITIVITY STUDY. Such a study is recommended in the conclusions as a pending task. However, a method cannot be considered robust or validated without analyzing its sensitivity because the input data may be unreliable. A sensitivity analysis would go beyond a mere case study to validate the conclusions in a more generalized way.
In addition, a discussion of the complexity of the method in terms of its practical application, etc., could also be included.
Point 6. CONCLUSIONS
The conclusions are well developed and contain the necessary elements. This reviewer only misses a section or paragraph with the limitations of the research. In my opinion, the conclusions section is a bit long to read but has precious information in terms of well-documented recommendations. I think the article would gain a lot in quality if the authors differentiated or grouped the general conclusions and the particular conclusions or recommendations to make the text more accessible and structured to the reader.
- Minor issues
- This paper needs a section/annex of the various abbreviations or acronyms that flood the manuscript.
- A tip to improve your impact. It is highly recommended to choose the keywords well so that they are easy to find (Life Cycle Assessment, LCA, Sustainability, Building energy renovation, and so on). The article would have much more visualization of these topics than with the current overly stilted terms. Something similar happens when the Abstract talks about the EN 15643-EN and 15978 standards, which refer to the sustainability of construction. Including this consideration already multiplies the interest and is in line with the journal's scope.
- The authors have not followed the style guide for authors of the journal. For example, the volume and page range in the journals have been omitted, in addition to not highlighting the year of publication, which facilitates tracking, as indicated in the authors' guide (e.g., 11, 16, and many more). Other references contain the above, although in the wrong order (e.g., 48).
https://www.mdpi.com/journal/sustainability/instructions
Author Response
Please find the answers to the review comments and the revised paper with track changes in attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
The research work presented is interesting and the paper well argued.
The aim of this paper is to investigate how the life cycle EI of renovation measures could be better estimated considering changes over time.
However, in dynamic LCA a greater attention is expected to both occupant behaviors (no users profiling, only a supposed increasing in average indoor temperature is considered) and to future environmental and social changes, as the increase of temperature and the rising demand for electricity and cooling, compared to the long-term scenario assumed (the builiding service life of 60 years from the moment of renovation).
Thus, a discussion could be useful on the the lack of available data on the occupants and on the technological progress and cleaner energy production in Europe and its impact on the effectiveness of the proposed dynamic approach for the estimation of the operational energy use.
Finally, according to the authors "The decision to renovate the building or further use the building as it is depends thus on the remaining service life of the building. The use of a static or dynamic approach does not change this decision." (lines 767-768). A clarification on this statement can help to better appreciate the results of this research.
Author Response
Please find the answers to the review comments and the revised paper with track changes in attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have addressed most of the comments. Only a few minor revisions are needed. Please find attached.
Comments for author File: Comments.pdf
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 2 Report
The authors have responded, to a greater or lesser extent, to the comments made by this reviewer. There are some comments that have not been adequately answered and they have chosen to avoid the question raised.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
