10.2 Type-Specific Base Cases & Saving Measures

10.2 Type-Specific Base Cases & Saving Measures

Exam Focus: Sub-topic 2.2.2 "Saving measures for specific building types" is the second half of Domain 2.0. The exam tests whether you know that the measure list is conditional, not universal.

A frequent candidate error is to treat the EDGE measure list as a fixed menu identical for every project. It is not. The App presents measures relevant to the selected typology, several measures are restricted outright, and the base case against which each measure is scored also shifts by type.

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Why the Base Case Moves With the Typology

The base case describes typical local practice for that building type. Consequently:

• A hospital base case includes continuous operation, high ventilation rates and substantial hot water demand; an office base case does not.
• A retail base case carries high lighting power density and long trading hours; a warehouse base case carries low occupancy and often no cooling.
• A residential base case, per the Methodology Report, assumes no solar shading devices, an un-insulated concrete roof, un-insulated plastered brick masonry walls and single-glazed metal windows, plus room air conditioning where A/C is used, conventional boilers for space heating and hot water where fuel boilers are chosen, a mix of incandescent, CFL, LED and T12 fluorescent lighting with no lighting controls, high-flow water fittings, and no reuse or recycling of water.

The consequence for practice: the same physical specification scores differently in different typologies, because it is being compared to a different reference.

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Natural Ventilation Is Defined Space by Space

The EDGE User Guide defines which spaces must be naturally ventilated for each building type in order to claim the measure. Each row is a separate measure in the software.

Two things follow. First, "the building is naturally ventilated" is not a claimable statement — the specific listed spaces must be. Second, note the automatic controls condition on hotel guest rooms: a guest room that can be left open while the air conditioning runs would waste energy rather than save it, so the measure requires controls that prevent simultaneous operation.

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Measures Restricted by Typology

Efficient refrigerators and clothes washing machines (EEM29)

This measure is only applicable to residential typologies (homes and apartment), hotels, resorts, serviced apartment and hospital typologies. Hotel and hospital typologies were only added to the measure in EDGE App version 3.1 — a version-dependency worth remembering, because a project modelled in an earlier version will not offer it.

The compliance rule is strict and all-or-nothing: the measure may be claimed only if all the refrigerators and clothes washing machines installed are energy efficient. If the project only has partial installation or partial provision, the project cannot claim this measure. Recognised rating systems include Energy Star, a minimum 'A' rating under the EU Energy Efficiency Labelling Scheme, or an equivalent level in a comparable scheme.

The practical trap: a developer who fits efficient appliances in the show units and standard appliances elsewhere has spent the money and earned nothing. The Expert must catch this at specification stage, not at site audit.

Ceiling fans

EDGE treats ceiling fans differently depending on local practice. In regions where ceiling fans are mandatory according to codes or common practices, the base case assumes the presence of ceiling fans, with base case fan power set at 60 watts per fan. Projects in those regions qualify for the measure by installing more energy-efficient ceiling fans, and the improved case assumes 40 watts per fan.

This is a clean example of the base-case principle: where fans are already normal, you do not get credit for having fans — only for having better ones.

Heated swimming pools

Heated pools require pool covers in all typologies. Covers are a low-cost measure that reduces evaporation, which cuts both the energy needed to keep the water warm and the make-up water consumed. For indoor pools, reduced evaporation additionally lowers the conditioning and ventilation demand of the pool hall.

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Cooling Plant Outside the Project Boundary

A documentation rule that catches teams on mixed-tenure and campus developments: where the plant for the cooling system is outside the EDGE project boundary or not controlled by the EDGE client, the team must provide a contract with, or a letter from, the management company in charge of the plant, stating the efficiency of the system, as part of the post-construction documentation. A district cooling connection does not exempt the project from evidencing plant efficiency; it changes who must supply the evidence.

Relatedly, where air conditioning is not specified at all, any cooling load is displayed as virtual energy — the subject of Section 12.1.

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The Base-Case Methodology Behind HVAC

For completeness on how the type-specific HVAC base case is generated: the EDGE v3 User Guide states that the base case HVAC system design follows the ASHRAE 90.1-2016 methodology, and that the base case system is calculated from the building type, number of floors and gross conditioned floor area. The earlier EDGE Methodology Report v2 cites ASHRAE 90.1-2007 for typical system efficiencies, so cite the version that matches the project's registration — this is a good illustration of why an Expert checks which User Guide version governs the project (Section 11.1).

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Working Method

Before promising any measure to a client, confirm three things: that the measure exists for the selected typology, that the App version governing the project offers it, and that the project can satisfy the measure completely rather than partially. Those three checks eliminate most of the measures that get struck out at Design Audit.