**4. Discussion**

## *4.1. Benefits of Using Energy Plus vs. Standard Method*

The results produced by the Mexican standard report and Energy Plus report show a variety of differences. The Mexican standard report considers the limited scope of heat gains and verification of standard compliance. Instead, Energy Plus offers a wide variety of possible results (depending on the simulation parameters selected) from energy demands to primary energy consumption (depending also on the level of detail in the model and definition of the project).

Energy Plus results and capabilities are already being used for building energy performance in several softwares and tools. For example, Giancola et al. recorded a map of energy saving potential with a geographic information system (GIS) by applying refurbishment measures and using simulation results [46]. Another direct application for the proposed

verification method includes building project management using Building Information Models (BIM). BIM management is a field recently popularized in the construction industry that involves applying a precise team work flow in different departments (structure, cost, engineering, installations, and architectural project) for correctly managing a project. By merging this BIM software with energy simulation software, the manager can analyze and integrate the results, so the pertinent design and engineering decisions can be made on time [47]. Auto-desk developed an energy simulation complement, Revit, for BIM software [48]. With the starting point provided by this research, an energy simulation complement for Mexico could be developed for a BIM management program.

Connecting the Energy Plus simulation tool with the Mexican standard could facilitate applicability to popular architectural and engineer tools on the market. In Spain, the authorities took advantage of simulation tools' practicality to make the energy certification process fast and easy for the construction industry. Therefore, Mexican authorities should follow the same path by starting to include the use of simulation tools for applying the energy standards.

Using the energy simulation engine, the user can obtain a wide range of results, but the results depends on the scope of analysis. Several options of simulation software are available on the market depending on the design process stage in which the user is involved (conception, project, or execution), and the complexity of the work (basic, intermediate, or advanced). Each simulation tool evolves from detailing and requirements, depending on if the user needs a basic program of intuitive interface tools or a specialized study with a wide scope (analyzing different project phases and application magnitudes) [49]. With Energy Plus, the user can enter other important building variables excluded by the standard, like occupation calendar, location characteristics, and HVAC equipment design. The new results allow the user to analyze other variables in addition to those considered in the Mexican standard results of thermal envelope heat gains, such as energy demands, primary energy used for building procedures, an estimated consumption of electricity and sanitary hot water, total hours where the set-point for comfort is not met, and the precise elements that have heat gains or losses (windows, walls, internal gains, soil, ceiling, etc.). Our results pave the way for a parametric analysis tool in the quest for a complete energy verification model. "The parametric analysis tool demonstrates the potential of parametric analysis, in finding optimal building envelope solutions in terms of operational energy, embodied CO2eq emissions and embodied energy. In the future, the parametric analysis tool may be used for setting energy performance goals and benchmarks, optimizing renewable energy and passive systems, integrating architectural features, minimizing changes during construction and integrating building systems" [50].
