1. What is an Energy Model?

An energy model calculates the heat flow in and out of a building. It measures the amount of energy that must be expended to maintain the ideal level of indoor comfort, thus the name Heat Balance Equation Method.

Since the "primitive hut", humans have always sought ways to improve their shelters and make even the most hostile environment comfortable. To combat hot/cold/wet/dry/or mild climates, or locations with poor air quality, high winds, seismic events, and/or resource scarcity, humans have developed building strategies to build ever-evolving shelters. Today, building science continues this tradition with rules and equations to combat these classic struggles and address the demands of the modern world (ie. human rights, growing populations, technologies, hyper-specialized building typologies, and, most importantly, climate change).

There are four key ingredients to an energy simulation:

Environment Recreation; using weather files, a typical climate season is simulated including everything from humidity, temperature, radiation, precipitation, evapotranspiration, wind, and more.
Building Model: every geometric configuration will result in a unique set of conditions and can help determine which strategies must be pursued to optimize the building's performance.
Mechanical building systems performance and strategies; the better compatible strategies become with the environment and the building design, the more efficient the design becomes.
Energy Codes, Building Standards, and Simulation Methodologies; the standards and equations that are used to ensure outcomes of your building meet the minimum safety and zoning requirements, as well as accurately measure the performance of your building design are key towards understanding what your baseline looks like and setting up targets to achieve.

2. Selecting Key Inputs

I. Selecting a Building Location

To create the environment for your energy model, you only need to decide where your building will be located. When starting a new project, users must add a building's location as a Street Address or Geo-coordinates. This input will select the nearest and most recent weather file, align the project with regional manufacturing costs and utility rates, carbon benchmarking using the Architecture 2030 methodology, and site your building in its real-world context.

If the placement in the site is incorrect on the 3D analysis page, refer to the video tutorial to edit the scene.

II. Selecting a Building Type

Building Type is a template used to differentiate the components of your building into their proposed energy & programmatic categories.

When selecting one of the 8 building templates, the user links their project to a set of standardized energy consumption & expenditure data, component efficiencies, and control strategies unique to their building type (i.e. the PNNL Prototype Buildings). Templates help initiate the project's inputs and jump-start the automation process. Building templates are also used to find the best fit for prescriptive inputs when the decision is based on the program and selecting relevant building products for cost optimization.

Learn more about Building Templates

According to the American Institute of Architects (AIA), the standard 8 types will cover 80% of all projects. However, for projects outside of these 8 standard types, users can further customize an existing template to model an unique use-type project. cove.tool supports an additional 60+ 2030 Building Types and hosts an article to guide the users in creating custom templates for your project (Example: K-12 schools, religious centers, gym, and more).

Projects with single-use type will have only one building type selected but mixed-use projects inside cove.tool can have up to 3 parallel building templates in a single cove.tool project. When creating a mixed-use project, the key is knowing where the building splits to a new function that demands different inputs for the spaces. Review the reasons you might want to create a mixed-use project, in these situations below:

Different Mechanical Strategies: For example, a hospital building with office spaces may need two system types to support the unique demands of the 2 spaces.
Different envelope properties: This situation occurs in most urban commercial spaces where store-front glazing is the first level and the rest of the project is an air-tight wall assembly. The two spaces need specific inputs for each space.
Different schedules: For example, a sports arena will have daily occupied office spaces, however, their largest energy expenditure, the stadium, and support spaces are used a couple of days out of the year. Since these spaces contribute to the EUI but have wildly different expenditures dependent on the calendar, it is important to split them to demonstrate their operations schedule.

A cove.tool support expert can always provide further clarification on template selection.

III. Selecting an Energy Code

Energy Codes set minimum efficiency requirements for new and renovated buildings, assuring reductions in energy use and emissions over the life of the building. Code buildings are more comfortable and cost-effective in operations, assuring energy, economic, and environmental benefits.

In cove.tool, the project's energy code is automatically selected based on building location. The selected code will load all the prescriptive inputs (envelope, lighting, etc.) on the Baseline Energy page. Other inputs, not specified by energy codes, are based on industry-standard practice, the ASHRAE User's Manual, and the PNNL Prototypes.

Available energy code options are listed here. Options include national (domestic and international), state/province, and local/city amendments to energy codes and standards. Furthermore, PNNL has a great article on understanding building energy codes and standards here, which breaks down the extent and demand for performance targets and regulations. We are always adding more standards and codes so if your country or code is not yet in cove.tool please let the support team know and any resources or links to the requested code version would be helpful too!

3. Building Geometry

There are 2 workflows through which you can analyze your building geometry.

I. Manual Mode

If you're in the early "napkin sketch" stage of design and want to estimate your future building's potential energy consumption, you can use the manual mode. This mode allows you to enter details such as wall, glazing, roof, and floor area metrics into simple text fields. Along with the building’s climate, area, and location, these details help provide initial insights into energy usage.

Manual mode is useful if you don't have a BIM Model and need to estimate the dimensions of different building components. Although it won't create a daylight model, it provides enough information to generate preliminary energy data. After entering the geometry manually, you should use the Facade Prototyping tool, which assists in exploring shading configurations and adding contextual elements to your estimated building geometry.

II. 3D Mode

For 3D mode, after creating your model with a modeling tool, you can integrate it via a cove.tool plugin. Each plugin, tailored to specific modeling tools, offers functions to smoothly transfer your model and includes resources like video tutorials and written guides to help you manage the plugin’s unique features effectively. These plugins extract area and coordinate details from your BIM file to recreate your building design on the Building Geometry page. The 3D Mode requires complete geometry uploads—floors, roofs, windows, walls, and building height—before it becomes available.

Once your model is uploaded, you can assign construction assemblies to your elements or move directly to the 3D analysis page.

Uploading through these plugins bypasses the Facade Guidance tool, taking you straight to the Baseline page. Note that shading configurations made on the Facade Page are not saved across the building until the geometry page is set to manual mode. Changes to your 3D model require re-uploading the building geometry. Each new upload automatically overwrites the previous one.

With these 3 steps completed, you are ready to set up your geometry for analysis so cove.tool can perform all of your building performance simulations. You can read more about the Building Geometry Interface here.

Happy Modeling!