Keywords

7.1 The Adopted Methodology for Demonstrating the Application of the BIM4EEB Toolkit in Real Environments

To demonstrate the effectiveness of the developed BIM-based tools and the suggested methodology as well as the conformity to project objectives, BIM4EEB proposes three pilot sites located in different European countries. Italy, Poland, and Finland were chosen because of their different climate conditions to prove the applicability of the toolkit. Considering a user-centric approach and particular attention to vulnerable inhabitants, the selected buildings are both social houses and residential apartments.

The first step of the demonstration consisted in the sensors set up within the chosen apartments in order to retrieve environmental information coming from apartments use and address specific project needs. Subsequently, several workshops succeeded one another to test qualitatively and quantitatively the toolkit. Finally, a KPIs based methodology was defined to validate the success of project objectives. The demonstration activity is composed of qualitative and quantitative workshops that were and currently are carried out in the three pilot sites. To test the toolkit a generic demonstration strategy, followed by a KPIs demonstration procedure, has been defined. Building owners provided data to the tool developers, who run a first preliminary test, analysing how the tool works. At this point, a demonstration workshop occurred with a double function: from one side to explain the use of the tool to building owners and users, from the other side to do a secondary evaluation and verify and solve any complications. Once the tool demonstration activity is complete, KPI demonstration was performed. For this purpose, a study to define the baseline to calculate the KPI and to verify the success of the project has been developed.

Some examples of demonstration activities follow:

  • data coming from sensors are visible in the BIM Management System and from other tools such as BIM4Occupants and BIMPlanner by the inhabitants and building owners.

  • BIMPlanner has been presented to the partners since March 2021. By applying it in the plans and progress site operations is possible to improve project monitoring and communication. Several regular workshops have been organised with the building owner in the Italian demonstration site, to present the tool functionalities and to discuss possible implementations.

  • BIM4Occupants has been successfully integrated with BIMMS platform to retrieve data from the Italian demonstration site. The demonstration of the tool to the inhabitants and building owners continues through workshops and support from technical partners.

  • BIMeaser was tested in qualitative and quantitative design workshops with the construction professionals using the Italian and Finnish demo sites to assess the time savings by using this tool with respect to the manual data input process of the scenario simulation.

  • Fast Mapping tool was tested in the three demo site in apartments and technical spaces.

As declared above, to test and verify the objectives of the project using the different applications, IoT devices and sensor systems have been selected and studied. Furthermore, several communication protocols such as Wi-Fi, Z-wave, Zigbee have been considered and chosen to meet the need. A hardware topology was defined to address the task requirements about:

  • Indoor environmental conditions (temperature and RH, illuminance, occupancy/motion),

  • Indoor Air Quality (IAQ) (CO2),

  • Electric power consumption.

Hence, different sensor devices were installed in the building case studies. A sensor hub with a connector and management function has also been installed to enable data integration from different sensors. This hub supports various communication protocols (Bluetooth, Z-wave and Zigbee), enabling hardware to data exchange and transmission. In addition, to collect the acquired sensor data, a system gateway was introduced. Sensors are linked to the gateway and due to the connection to its Application Programming Interface (API) data can be transmitted and stored into the BIM Management System, developed within the project, and performing the function of a data repository.

7.2 Description of the Demo Sites

The three Best Practice examples are residential buildings and social houses in Italy, Poland, and Finland. Description about the building itself and its main characteristics as well as the selection of apartments are presented for each specific pilot site. Renovation interventions, if present, are also outlined.

7.2.1 The Italian Demo Site

The Italian demonstration site is located in Monza, one of the biggest cities in northern Italy, in Via della Birona 47. The building, completed in 1981, is a residential social housing managed by ALER Varese—Como—Monza Brianza—Busto Arsizio (ALER VCMB), and it is structured on nine floors for sixty-five apartments in total. It is composed of plastered external facades and fair-faced concrete stairwells and fronts (Fig. 7.1).

Fig. 7.1
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Italian demonstration site

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The conservation status of the building is relatively poor. There are signs of loss of plaster and flooring as well as damage to the concrete cortical surface. To improve the performance of the residential building, two activities are being carried out. On the one hand, the realisation of insulating facade coat and the replacement of external windows with PVC windows are the main renovation interventions currently taking place. On the other, environmental sensor devices were installed to make apartments smarter and improve their performance.

The selection of individual apartments relied on residents’ availability considering more cooperative families during the installation phase and data collection. Secondly, the choice was based on diversification related to exposure and different levels of the building (low, medium, high/ stairs A and B) and detailed analyses of the technical condition of individual apartments. Therefore, thirteen apartments have been individualised according to tenants’ availability, exposure, and technical conditions. The selected apartments and the main characteristics of interest for the positioning of sensors are summarised in Table 7.1.

Table 7.1 Main characteristics of each apartment
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Selected apartments where to install sensors are two and three-room flats. The multipurpose sensors—measuring temperature, humidity, occupancy, and illuminance—were installed in the living room and the master bedroom, both in a two and three-room flat. The Indoor Air Quality (IAQ) sensor was placed only in the living room because it is considered the room of the house where the inhabitants spend most hours, assuring a more significant data collection. In the energy meter room, the electric energy meter was installed. Finally, one sensor hub for apartment was installed for acquiring data from different sensors. The electric power meters were then installed directly in energy meter rooms of the apartment and connected to dedicated hubs. Hence, sensors and meters were installed in the case study according to the distribution in Table 7.2 and Fig. 7.2.

Table 7.2 Sensors set up in Italian demo site
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Fig. 7.2
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Distribution of sensors in the Italian demo site

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7.2.2 The Polish Demosite

The polish pilot site is in the south of Poland in Chorzow town. The object of the study is a residential building built in 1902 characterised by 5 floors, 12 apartments and 3 commercial areas located on the ground floor, for a total of 1330 m2. The data available come from different sources, both digital and on paper and from on-site inspections. Geometric and topological data about the generic aspect of the building for preliminary assessments are available, while data regarding apartments are extracted from original 2D drawings. The building itself would assess mainly the design and planning functions of the platform, fast mapping capabilities and application of digital tools for HVAC design, operation, and efficiency management with the input of HMI and occupant ́s profiling mechanism. Unlike the Italian demonstration site, no renovation involving construction work was planned or required (Fig. 7.3).

Fig. 7.3
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Polish demonstration site

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The selection of apartments for demonstration activities on the Polish pilot site was based on detailed analyses of the technical condition of individual apartments and according to the strong need for inhabitants to undertake further renovations (in some apartments, renovation works were carried out previously). Moreover, the availability of inhabitants and diversification of flat expositions were considered.

After site inspections, some general conclusions about the building technical state have been collected:

  • The electric installation has cables that cannot stand the current, resulting in low possibilities of power supply. One apartment cannot have electric devices installed. The electric installation requires complete renovation in another one.

  • Every shaft would need additional revision and cleaning, so that the natural ventilation would be possible. Three apartments have problems with shafts, and reverse thrust.

  • Most of the apartments would require a change of boilers and distribution of domestic hot water.

  • Radiators should be changed if working with lower temperature fluids.

  • Piping, in general, is in good state, however, six apartments require a complete change of the system.

  • There are two apartments that are unconditioned.

  • Humidity issue in the apartments. The right wing of the building is suffering major humidity problems, with mould in four apartments.

In polish case study mostly two bedrooms apartments were selected for the installation of the sensors. Equipment installations consider inhabitants preferences, basic presence, and technical limitations of devices. The Indoor Air Quality (IAQ) sensors were installed in the living rooms. Multipurpose equipments measuring temperature, humidity, occupancy, and illuminance were installed in the bedrooms. Electric energy meters were installed inside main technical shafts which combine meters dedicated to each apartment. Sensors, hubs, and meters were installed in the case study according to the Table 7.3.

Table 7.3 Sensors set up in Polish demo site
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7.2.3 The Finnish Demo Site

The Finnish pilot is located in Espoo, in Southern Finland near Helsinki. The actual building. which was originally built in 1992, is a five-floor apartment building owned by Finland’s largest pension provider KEVA.Footnote 1Keva invests its funds also in real estate with the responsibility focus on property energy efficiency. Keva’s goal is to become carbon neutral by the end of 2030 in terms of carbon emissions from the energy used in its direct real estate investments.

The building covers a total of 4100 m2 floor area. The building was brought under the BIM4EEB project as an energy renovation project from Caverion. The demonstration pilot for the BIM4EEB project was changed in the middle of the project due to COVID-19 pandemic caused a delay in the first apartment building renovation project that did not fit into BIM4EEB schedule. Some of the tools of the BIM4EEB project were tested on the earlier pilot building. BIMeaser was used in energy simulation for selection between different heating system upgrade options that could have been installed on the first building (Fig. 7.4).

Fig. 7.4
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Finnish demonstration site

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After the pilot building change, the heating system of the new building was upgraded with the addition of an exhaust heat recovery system. The goal of the renovation project was to extract the excess heat from the HVAC system to enhance the performance of the district heating system during the heating season. The planning and installation works were done in collaboration with Caverion and a sub-contractor Tom Allen Senera Oy. The renovation works and testing of the system were conducted during Q3-Q4 of 2021. All the installation works were done on the facility areas with no work in apartments due to privacy and health reasons during the pandemic. The progress of renovation works was monitored with weekly online meetings between Caverion, VTT and Tom Allen Senera Oy. Different phases of the installation works were collected and reported to BIMPlanner tool to assess the planned and actual progress of the project. A demonstration day to test the Fast Mapping tool with RISE and Caverion was held to model an IFC file of the boiler room where the installations were made. The project on site was finished in January after final inspections (Fig. 7.5).

Fig. 7.5
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Finnish demo site boiler room with the new heat exchanger

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7.3 BIM4EEB KPIs Framework and Validation Methodology

The Key Performance Indicators (KPIs) are used to estimate the level of success of the project and assess the achievement of planned and defined objectives. The selection considered KPIs that follow the needs of the project and can assess its results.

KPIs are divided in “mandatory” and “secondary”. Mandatory KPIs are based on BIM4EEB objectives, and they are in line with the stakeholders’ requirements. They need to be addressed during the last phase of the project. While the Secondary KPIs relate to the literature analysis and the review of project use cases and tools.

Moreover, considering the different interests of the project from the renovation process to the energy performance passing through users’ comfort, BIM4EEB KPIs have been grouped in the following six categories: “renovation process”, “energy performance”, “comfort”, “economic”, “social”, “environmental”.

“Renovation process” category is related to the specifics of the renovation process such as time and cost, “energy” is connected to the energy requirements and performance of the renovated buildings such as energy consumption, energy saving, life cycle assessment parameters, “comfort” refers to occupants thermal, visual and building acoustics comfort, “economic” KPIs regards the feasibility of buildings renovation regarding cost, life cycle costs, project profitability and LCC assessment, “social” KPIs investigate stakeholders’ such as designers, construction companies—FMs, occupants) perception and “environmental” category is related to CO2, CO, PM, VOCs.

Finally, not all KPIs are applied to the developed BIM-based tools. They are addressed according to the peculiarities of the single tool. Consequently, since not all developed BIM-based tools have been tested in the three demo sites of the project, the KPIs are different according to the considered demo site too (Fig. 7.6).

Fig. 7.6
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KPIs framework: KPIs grouped in mandatory and secondary, and according to demo site and BIM-based tool

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For KPI calculation, a precise formula has been defined in the project deliverables and associated with each KPI in order to be measured. Hence, it is necessary to calculate specific parameters to assess the level of success. Especially, a baseline, which is a reference parameter corresponding to the traditional renovation process, has to be taken into consideration in the most relevant cases.

For the sake of clarity an example of mandatory KPI is proposed. Among “renovation process KPIs”, Renovation Time Reduction is a KPI defined to assess the time saving occurred during the renovation process due to improved management of the renovation activities.

7.4 Tools Application in Real Environments

At the date of writing this manuscript, the process of demonstrating the tools is still in progress, which is why only a few indicative results are given, outlining the main processes identified and tested, as well as some of the results obtained.

Below is a breakdown of these contents among the tools that are part of the project.

7.4.1 BIMMS

The BIMMS functionalities were tested and demonstrated in the Italian, Polish and Finnish demonstration sites. The BIMMS was used to store documentation, models, and drawings along with the continuous data streaming coming from IoT devices installed in the dwellings (Fig. 7.7).

Fig. 7.7
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Some functionalities from the BIMMS

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The BIMMS’ SPARQL Endpoint was available as an interface to share and query the project data to the authorised stakeholders and helped to improve the knowledge about the surroundings (environmental, social, and administrative data) retrieving additional data used to enrich the BIM models (Fig. 7.8).

Fig. 7.8
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Geo linked data of the Italian demo site

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The demonstration activities allowed to use and test the REST API interfaces to update interactively the IFC BIM model demonstrating that the technology is ready and can support faster workflow that can avoid some bottleneck tasks (export-upload-download-import) typical of traditional file exchange methods.

The stakeholders evaluated the BIMMS and gave positive feedback stating that the user interface has an intuitive design and the functionalities provided allow them to exchange information, monitor the construction works, and manage the building data in more effective way compared to a traditional renovation approach.

7.4.2 Fast-Mapping

By using the fast-mapping toolkit, the user can by the help of a laptop, AR glasses and a sensor stick:

  1. 1.

    map what’s inside the construction,

  2. 2.

    create IFC-files out of the mapping results and real geometry in 3D.

The mapping result might be used when to decide about a renovation or just for documentation. The created IFC-files will be used in the BIMMS system and/or as an illustration when discussing renovations with stakeholders.

The function of the fast-mapping toolkit was tested in the different demo sites (Italy, Finland, and Poland). In Italy one empty and one occupied apartment were used and in Finland an equipment room and in Poland an occupied apartment.

The demonstration included:

  1. 1.

    scanning the considered rooms by an Imager 5010.

  2. 2.

    creation of point clouds out of the scanned rooms which were downloaded to the laptop and then transferred to the AR glasses. The AR glasses was a HoloLens2.

  3. 3.

    opening the point cloud in the HoloLens2 and align it with the reality.

  4. 4.

    mapping the rooms with the sensor stick.

  5. 5.

    create IFC-files in the HoloLens2 out of the reality in combination with the point cloud (Fig. 7.9).

    Fig. 7.9
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    From left, 1. laser scanning, 2. Point cloud downloaded to the laptop, the program used is named companion app, 3. Mapping the wall in the room by the sensor stick

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7.4.3 BIMeaser

The BIMeaser test results have shown that the modelling is faster with the digital BIM assisted process compared to the manual modelling. The digital and traditional approaches were compared in the testing. The easy application of renovation measures and reviewing the results contribute positively to the overall modelling time in BIMeaser process. The overall increase in modelling time reduction is more than 75% with BIM assisted process compared to manual modelling. In addition, the BIM-assisted BIMeaser process also brings data accuracy and helps to avoid modelling errors, which are quite common in the manual approach (Table 7.4).

Table 7.4 Time savings compared to traditional energy simulation in two real world case studies
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7.4.4 BIM4Occupants

As stated above, the building occupants should be able to get insights about contextual conditions in building premises, personal comfort preferences and further comfort and energy-related analytics. In addition, the building occupants oriented framework allow building occupants to receive notification and alerts on ongoing works, receive safety hints and information (e.g. to avoid specific areas where works have not been finished yet), while on the other hand, enabling them to upload information that might be requested ad-hoc by contractors or any other relevant input they may consider useful, thus contributing to the constant and collaborative updating of BIM and as-built documentation. Indicative screenshots from the demonstration activities of the project are presented in the following figures (Figs. 7.10 and 7.11).

Fig. 7.10
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Renovation scheduling view

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Fig. 7.11
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Example of safety alerts

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The outcome of this tool will further facilitate the building stakeholders to get insights about occupancy and comfort conditions in premises as well as properly plan the renovation activities of the project. Indicative results from the analysis performed at demo premises is presented in the following figures (Figs. 7.12 and 7.13).

Fig. 7.12
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Occupancy profiling results

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Fig. 7.13
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Thermal comfort profiling results

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The following are some of the  Key insights:

  1. 1.

    Post processing and data handling of sensor data is required.

  2. 2.

    The analysis can extract useful results in terms of occupancy and comfort that may lead to:

    1. a.

      Better simulation of energy and building performance.

    2. b.

      Better operation of the building environment.

    3. c.

      Increase user comfort and productivity.

  3. 3.

    While the framework was tested at residential premises, the same applies also for office buildings and thus the overall framework is replicable.

7.4.5 BIMcpd

BIMcpd stands for BIM Constraint Checking, Performance Analysis and Data Management. The tool is a user-friendly self-intuitive software suite designed to reduce processing time for constraint checking, increase building energy performance knowledge, standardise building energy data and help users to make informed and better decisions. The software is developed for Building Services Designers, MEP engineers, M&V Practitioners, Energy Auditor, Building Energy Managers, ESCO’s, Research Performing Organisations.

BIMcpd contain three distinct intuitive applications that will allow users to (a) find recommended positions for HVAC, lighting, and other devices; (b) manage the data that they have on the above and create new data sets that they can share with other tools and (c) analyse data from sensors, energy bills, and other sources.

The Constraint Checking Tool is designed to extract information from an IFC file and compare it with data stored in the BIMcpd database, which allows the values from the model to be checked to ensure they are compliant with existing building codes, such as ventilation or lighting regulations (Fig. 7.14).

Fig. 7.14
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HVAC Layout in BIMcpd Constraint Checking Tool

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The BIMcpd Data Management tool allows for the upload of data from import files in which the fields can be mapped in order to standardise the way that the data is being imported. Alternatively, data can be imported automatically from preconfigured sensors, and this was the method used in importing data from the demo sites.

Finally, the Performance Evaluation Tool follows the Measurement and Verification (M&V) process and principles, allowing data uploaded using the Data Management tool to be modelled. It allows for data manipulation, such as data filtering and outlier detection to increase the accuracy of the results (Fig. 7.15).

Fig. 7.15
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Comparison of temperature across 4 apartments from Italian demo site

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7.4.6 BIMPlanner

The BIMPlanner tool was tested for detailed scheduling and tracking of site activities in Italian and Finnish demonstration projects. As the demonstration projects were quite different in renovation content and extent the BIMPlanner testing focused on slightly different topics in these projects.

In Italian demonstration project was arranged a few common workshops with major project partners to introduce the tool and basics of the location-based planning and management method. With this background knowledge the personnel involved in the renovation project implemented the testing with help of researchers from Polimi. The testing was partially hampered by some external factors, mainly Covid-19 lockdown, and some material shortages in Italian market during renovation. The testing mainly concentrated on two activity types: façade renovation and internal windows exchange.

In the following is presented an example of window exchange planning including communication with the occupant of an apartment. In BIMPlanner the activities can be scheduled by work locations which means that e.g., the window exchange activity can be given planned times independently for each apartment. In preparation of the actual scheduling, the work locations are defined in a specific BIMPlanner view called Location-breakdown-structure (LBS). Figure 7.16 shows an example of the definition of work location “apartment H” (alloggio H) and in 3Dview are shown the IFC space objects attached to this work location. Those IFC-objects are the linking identifiers to share correct activity information to other BIM4EEB tools.

Fig. 7.16
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Example of work location definition of “apartment H” with linked IfcSpace-objects in 3D-view

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When the contractor creates new scheduling data for the apartments, the BIMMS tool retrieves this data and transfers data to BIM4Occupant tool to be shared with individual occupants of apartments based on common identifiers of the apartments.

The occupant may decline the contractor’s initial schedule and propose new timing for the activity. In Fig. 7.17 is an example where the occupant has proposed new timing for window exchange within two days’ timeslots.

Fig. 7.17
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Example of occupant’s proposal of new timing for the activity in specific “apartment H”

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After the contractor receives the occupants’ response the rescheduling will be done and new timing shared with the occupant. In Fig. 7.18 is an example of final scheduling for one certain day for window exchange in this apartment.

Fig. 7.18
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Example of the final schedule for “window exchange” in “apartment H”

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The testing in Italian demonstration project indicated some needs for the further developments of BIMPlanner and possibilities to test some other planning scenarios. The definition of the work locations was manual work although it needs to be done only once. If the apartments are defined systematically in IFC-data and can be extracted from other spaces and zones of the building those can be converted more automatically as work locations in the location-breakdown-structure of BIMPlanner. At minimum this would require guidance on what apartment identifiers shall be used in modelling and developing automated interpretation functionality in BIMPlanner. In the planning sense an alternative approach could be tested: the contractor could propose the initial schedule with a longer timeslot at floor level (i.e., same time period for all apartments in the floor) and let occupants to select the specific times for their apartments within a given timeframe.

The Finnish demonstration project was a specific energy renovation with the installation of an exhaust heat air pump in a residential multistorey building. The renovation activities were implemented only on the roof, one part of the façade and the boiler room. Those were defined as work locations in BIMPlanner. But in general, there was no repetition of the different activities over the work locations that are typically managed with location-based management method in which BIMPlanner is based on. In this demonstration project the BIM4Occupant tool was not tested either so there was no information sharing with tenants of the apartment or commercial premises with BIM4EEB tools.

However, BIMPlanner was used in project management and on weekly basis was created or refined next week's plan and recorded the actually started and finished activities. The testing revealed the fact that the total schedule was not tight and contained lead times that were reserved by the subcontractor to minimize the possible schedule risks. During implementation there were no major delays and the schedule risks were not realised. In theory, the initial planned duration of 13 weeks could have been reduced by around 3 weeks and get some savings of the time-related costs. If such energy improvement systems could be installed in larger building stock instead of individual building such savings would be possible and achievable, and training effects would improve the overall productivity.

The BIMPlanner is based on the use of IFC model for defining the work locations and to use identifiers of the BIM-objects to communicate with other BIM4EEB tools. In renovation of residential buildings this sets a constraint as the design is not usually done with modelling in typical cases and BIM is not existing. However, BIMPlanner does not require a detailed design model. In the Finnish demonstration project, the BIM was created with a reasonable amount of work by reading pdf-floor plans in modelling tool and raising those in 3D (Fig. 7.19). Some additional work was needed in placing e.g., windows and doors in place and adding some data like room and apartment identifiers in the model. Such a simplified model can be and was used also for BIM-supported energy simulations with BIMeaser tool.

Fig. 7.19
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Simplified BIM of the finnish demonstration project

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7.5 Lessons Learnt

The focus of the project is on the digitization of methods and processes related to the construction sector, hence the proactive involvement of different stakeholders even if with minimal digital skills, but open to learning is required.

In this context, any individual involved in the process has to be included in dissemination activities and introduced to the use of tools and systems in order to stimulate personal or professional curiosity in tool use, highlight the advantages and increased possibilities of the new proposed approach, lay the foundations for a relationship of trust. A satisfied user is a key factor for a successful proposal and this success can be measured through the number of accesses to the tools as well as the quality of the results that can be produced. The BIM4EEB dealt with different stakeholders involved in the process, both professional (i.e., whose purpose in using the tool is related to the optimisation of the work process) and users who gain personal benefit from the application of the tool as the inhabitants of the demo sites.

The process of installing, managing, and integrating the tools must be straightforward from the very first start, encouraging user's autonomy in managing the information. A preliminary feedback from the questionnaires submitted to professional users shows general ease of use of the tools, even if technical support is not completely excluded. The increased data interoperability among the developed tools is also intended to reduce the time and cost of the activities. Hovever, it is true that some tools (e.g., scanning and modelling tools) require both equipment and specific skills that need dedicated training and users' competence improvable by continuous practice.

Regarding time and cost management, the application of lean construction practice processes requires weekly or bi-weekly planning that should be actively supported by the general contractor and the other stakeholders involved. An effective approach involves a tool able to support the designer, but at the same time able to guarantee flexibility in managing the organisation of activities and sub-activities. This is particularly true when the process requires the presence at the site of sub-contractors assigned to dedicated tasks. However, it is essential to formalise the information framework and the flow of data, but from the owner’s point of view this is reasonable only if added value of the up-to-date digital data of the site operations can be identified. These data should reduce the need for control resources and costs and/or result in better decisions for project control. The compensation of providing these data to client is even more pressing in cases of uncertainty periods such as the one related to COVID-19 and shortages of construction materials particularly in the Italian case. The content and characteristics of a renovation project may vary considerably, and construction management methods shall be applied accordingly. In full scale residential renovation projects common methods that are used in construction in general can be applied. In limited energy improvement interventions when there is no full-time site manager and workers of different disciplines operate at site separately, these construction planning and control methods may not be the best approach. In such cases creating an application of remote workforce management methods used for example in facility management services should be considered.

A measure of the quality of the proposed interventions, as well as the state of the buildings involved in the project, can be known by the building owners thanks to the environmental sensors installed inside the flats.

To assess the environmental variables, it is necessary to have dedicated and appropriate types of sensors that guarantee hardware interoperability, and a have a correct position in order to obtain representative measurements of the context. For this purpose it is necessary to keep in mind how occupants' preferences for the installation, as well as the presence of fixed furniture, can influence the repeatability of the positioning within the different housing units.

Focusing on the inhabitants, although there has been a general good acceptance of the installed devices, the use of single multi-sensors devices able to measure different environmental variables is recommended, allowing a minimum perceived invasiveness inside the flats. Wherever possible, a battery installation is preferred by the inhabitants, both to avoid a burden on consumption and on the availability of sockets in the rooms. One of the requirements, particularly true under COVID-19 restrictions, was also to minimise the number of interventions and accesses inside the flat, but this kind of installation requires an additional maintenance burden to replace the batteries.

Concerning the population of occupants and adding the social housing context, it is clear that we are dealing with an elderly population with limited technological and digital knowledge, as well as devices suitable for the purpose. A longer introduction process is therefore necessary, defining periods of support and interaction and data management assistance.

The presence of real-time alerts and feedback also improves both the interaction and the user's understanding of the data, even if they require an additional effort from the building owner side. The possibility provided to the occupants to communicate their availability regarding the renovation activities that will take place in their flat, as well as the possibility to report any inconvenience due to the process, has been shown to improve the communication relationship between building owner and resident. However, this process requires attention from the building owner to ensure a prompt response and management of the file.

As the toolkit is based on BIM technology, efficient use of the tools could improve by broadening the knowledge in this field by renovation process participants.