Efficiency Gap Caused by the Input Data in Evaluating Energy Efficiency of Low-Income Households’ Energy Retrofit Program

Round 1

Reviewer 1 Report

The paper analyzed the effect of input data in calculating energy-savings to address the “efficiency gap” in low-income households’ energy-efficiency programs.

The paper presents an ideal topic and introduction appropriate for the Sustainability Journal; however, the article needs to undergo a significant revision. In my opinion, the paper cannot be published in its current state.

The summarized comments are as follows:

How did the authors decide to select the additional insulation reinforcement? It would be preferable to have the authors outline how they selected 30mm thick insulation, 12mm thick layer, and a 9.5mm thick gypsum board, etc. of many measures. The field measurement processes are not well elaborated. For example, how did the authors measure items such as SHGC, UV, Visible light, and infrared transmissions for both pre-retrofit and after retrofit? Please define the simulation process/methods for the understanding of your readers accurately. For example, what role did the EnergyPlus played in the simulation analysis and the results? Line 187, the Authors made a statement, “This information is combined with local climate conditions and fed into computer-based audit tool.” What type of audit tool and how does it influence the audit process and results? There is no Table 1, please insert Table1 or rearrange the Tables. The authors should adequately address the efficiency gap, which seems to be the central idea of this paper. The discussion and conclusion should be significantly improved, avoiding as much as possible what has been described in the literature. Minor plagiarism detected in the introduction section. They include direct quotes from references 12, 13, E2e working paper 2020, Evaluating the evaluation: https://www.sciencedirect.com, and evaluating digital transformation strategy.

Author Response

Dear reviewer,

 

Thank you for your kind review and comments. We have modified the manuscript accordingly.

 

(1) How did the authors decide to select the additional insulation reinforcement?

It would be preferable to have the authors outline how they selected 30mm thick insulation, 12mm thick layer, and a 9.5mm thick gypsum board, etc. of many measures.

 

The manuscript has been revised as your comments as follows;

 

è Through a retrofit project, an additional insulation reinforcement was conducted with a 30mm thick insulation (extrude polystyrene), a 12mm thick air layer, and a 9.5mm thick gypsum board on the inside wall according to the Building Design Criteria for Energy Saving (BDCES) in Korea. BDCES is a mandatory regulation for new construction building or retrofitted building projects in Korea and defines the insulation performance of the building envelope [25]. (2nd paragraph in “2.1. Overview of the target household”).

 

(2) The field measurement processes are not well elaborated. For example, how did the authors measure items such as SHGC, UV, Visible light, and infrared transmissions for both pre-retrofit and after retrofit?

 

è  The performance of the window was measured by the ‘Window Energy Profiler’ device (Fig. 6(a)) and the airtightness performance was performed by the Blower Door Test method (Fig. 6(b)). Added pictures of measuring equipment in Fig. 6.

è Explanation has been added to the revised manuscript (2nd paragraph in “2.3. Detailed field measurement”).

 

(3) Please define the simulation process/methods for the understanding of your readers accurately. For example, what role did the EnergyPlus played in the simulation analysis and the results? Line 187, the Authors made a statement, “This information is combined with local climate conditions and fed into computer-based audit tool.” What type of audit tool and how does it influence the audit process and results?

è According to your suggestion, more explanation about walk-through audit process and Energy audit program in “2.2 Walk-through audit”.

è The work-through audit process are as follows: (1) On-site visit, (2) Checklist before construction, (3) Energy audit before construction, (4) Construction & checklist, (5) Energy audit after the construction.

è The energy audit program (tool), as shown in Fig. 4., is used in steps (3) and (5). This process is shown in Fig.3

è Enerygplus program is not used in the walk-through audit process. It was used to indicate the quantitative difference of the heating load that the diagnostic value in the 'Walk-through audit process' differs from the actual value in the ‘Detailed measurement’. The role of Energyplus has been added to “2.4 Simulation”.

 

 (4) There is no Table 1, please insert Table1 or rearrange the Tables.

 

è It has been revised.

 

 (5) The authors should adequately address the efficiency gap, which seems to be the central idea of this paper.

 

è In the “1. Introduction” and “4. Discussion and conclusion”, this paper added an explanation of the ‘efficiency gap’ arising from the energy retrofit program for low-income households in Korea.

è It is shown through field measurements that the prediction of energy retrofit method through walk-through audit in Korea is different from the actual energy saving effect value. This causes the input value to play an important role in the predictive evaluation of energy usage before and after retrofit, but it is difficult to measure accurate input value with a limited budget, considered convenience of filed workers, and time. In this paper, to reduce the efficiency gap in the retrofit program, accurate energy diagnosis must be prioritized and costs applied to it must be prioritized.

 

(6) The discussion and conclusion should be significantly improved, avoiding as much as possible what has been described in the literature.

è According to your suggestion, more explanation has been added to the manuscript in “4. Discussion and conclusion”).

 

(7) Minor plagiarism detected in the introduction section. They include direct quotes from references 12, 13, E2e working paper 2020, Evaluating the evaluation: https://www.sciencedirect.com, and evaluating digital transformation strategy.

è It has been revised.

 

All modifications are highlighted in red in the manuscript.

 

Thank you for your kind comments. 

Reviewer 2 Report

The paper is interesting. However it needs to be improved. 

In the introduction, I recommend formulating the purpose of the paper.

Discussion of results should be extended. It is worth referring to literature from different countries.

Author Response

Dear reviewer,

 

Thank you for your kind review and comments. We have modified the manuscript accordingly.

 

(1) In the introduction, I recommend formulating the purpose of the paper.

 

The manuscript has been revised as your comments as follows;

--> The purpose of this study is to show the problems of diagnostic methods in the energy retrofit program in Korea currently being implemented to low-income households. As a result, a simulation evaluation using performance measurement values that an efficiency gap may occur. Although the detailed performance evaluation through measurement is difficult due to, such as time, financial problems, and convenience of a field worker, the current walk-through audit assessment shows to the reader that it shows inaccurate predictions through the detailed measurement and simulation results.

--> The purpose and structure of this paper was further described in the last graph of ‘1. Introduction’.

 

(2)    Discussion of results should be extended. It is worth referring to literature from different countries.

 

The manuscript has been revised as your comments as follows;

 

--> The research results were additionally specified in the '4. Discussion and conclusion' section.

--> The contents are as follows:

The results of this study emphasize that one of the causes of the efficiency gap or efficiency difference is due to the input values in evaluating the energy performance in the retrofit program of low-income households. According to the results of this study, the energy saving effect according to the retrofit of the low-income household predicted through the results of detailed measurement was 65%, higher than 41% of the conventional prediction method. The resulting GHG reduction effect was also the same as the energy savings, and the results predicted by the existing prediction methods were less predicted than the detailed measurement results. This is because the energy performance evaluation of the target building before the retrofit depends on the walk-through audit, so it is not considered to reflect the deterioration due to the aging of the building and there is a tendency to judge the thermal performance of building envelope better than it is. Although sufficient retrofit and precise and detailed measurements are not possible with a limited budget, it seems somewhat unreasonable to establish a national building energy saving policy with these results. Energy diagnosis that prioritizes the convenience of field workers, and energy efficiency by retrofit that is evaluated based only on the walk-through audit results, can lead to very different results from actual efficiency. For the energy efficiency improvement program for the low-income household to realize efficient energy saving and comfort for residents, energy diagnosis must first be appropriately conducted. In this sense, it is important to increase the subsidies for energy improvement programs for low-income households, as well as to set energy performance diagnostic costs properly.

 

All modifications are highlighted in red in the manuscript.

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have made significant improvements to the manuscript, adhering to all my suggestions. Though the novelty of the paper is quite low, I will still recommend it for publication.