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Montreal Retrofit Workflow
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**Purpose**: To perform a cost-benefit analysis comparing different levels of building retrofitting.

**Methodology**: Utilizes the INSEL monthly energy balance, CO2, and cost workflows as a base to calculate Energy, CO2 emissions, and Cost values for each retrofitting scenario.

**Defined Scenarios**:

    **R0** - Business as Usual: Represents the current state of the building. Energy systems are replaced at end-of-life with identical performance.

    **R1** - Envelope Improvement: Improves walls, windows, roof, and basement to meet current legislative standards.

    **R2** - Systems Optimization & PV:
        HVAC systems are updated to an aero-thermal heat pump coupled with baseboard heaters for peak loads (combined seasonal COP of 2.79).
        Utilizes available roof space for Photovoltaics (PV), provided the shaded area is less than 30% of the total roof area. Panels are installed at a 35º slope.

    **R3** - Comprehensive Retrofit: A combination of scenarios R1 (envelope) and R2 (systems + PV).