What is TEDI?

Thermal Energy Demand Intensity, TEDI

Akshay Padwal avatar
Written by Akshay Padwal
Updated over a week ago

Thermal Energy Demand Intensity - TEDI is the annual heating energy demand for space conditioning and conditioning of ventilation air. In other words, TEDI is the amount of heating energy that is output from any and all heating equipment per unit modeled floor area. The heating equipment includes hot water, gas, electric or DX heating coils of the central air system, and any other equipment used for space conditioning and ventilation. Also, the heating output of any heating equipment whose source of heat is not directly provided by a utility must be counted towards the TEDI. Important to note that TEDI does not include mechanical efficiencies of equipment.

TEDI is formulated as the summation of space and ventilation heating output divided by modeled floor area and is reported in kWh/m2/year. Recently more locations globally are utilizing TEDI as part of their compliance pathway. For example, British Columbia, Canada formally utilizes TEDI to improve building envelope performance. In addition TEDI is a helpful metric in heating-dominated climates and is displayed for all projects in Canada.

Formal Equation City of Vancouver Energy Modelling Guidelines version 2.0

Location of the TEDI output on the Baseline page.

What impacts the TEDI value?

The key inputs which have an impact on TEDI are listed below:

  • Envelope Performance Inputs (such as Wall, and Roof U-values)

  • Heat Recovery System

  • Building Energy Management System

  • Ventilation Control

  • Exhaust Recirc. %

What does not impact the TEDI value?

  • System Type

  • Heating System COP

Why consider TEDI at all?

As opposed to EUI, TEDI only considers the design aspects that limited the overall demand for heating in a building. By targeting low TEDI, designers focus on passive solutions like good insulation, air tightness, and beneficial sun angles that help reduce energy use directly. Looking at these passive design aspects is always the first step in a high-performing design.

TEDI for Massachusetts

Massachusetts 10th Edition Energy Code also using TEDI for one of the compliance pathways. The definition is similar to what is used in Canada, however the specifics of the calculation are defined directly based on building type. Please refer to Massachusetts Energy Stretch and Specialized Codes Guide for details on calculating TEDI for projects in Massachusetts. It is recommend to utilize loadmodeling.tool and the EnergyPlus Tabular Output Report in order to determine a projects TEDI for Massachusetts projects.

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