Draft. These pages were imported from the ARC Technical Criteria document (16 April 2026) and have not yet been reviewed in this format. Several thresholds are still being settled and are flagged on the pages concerned.

Zone 1 - mechanically cooled and ventilated

What a mechanically cooled and ventilated space must do, including ventilation when air conditioning is running.

Zone 1 areas must be able to operate energy-efficiently in mechanical cooling and ventilation mode – and for less harsh climates to be able to turn off the mechanical systems and operate effectively in natural ventilation mode when external conditions allow. Dehumidification (‘latent cooling of the air’) should be optimised with air cooling (‘sensible cooling of the air’) if suitable equipment and controls are available. Ventilation of rooms, for when air-conditioning is running, may be a continuous mechanical extract ventilation (MEV) fan (either for individual rooms, or using a larger extract fan serving several rooms) with fresh air supply to each room via trickle vents, or a mechanical ventilation system to supply fresh and extract stale ventilation air from rooms with ‘coolth’ recovery (MVCR) - if budget and supply chain allows.

Air-conditioning without adequate room ventilation is strongly discouraged.

The diagrams at the end of this section, illustrates measures for typical zones 2 & 3 spaces and then shows the additional measures likely to be needed to ensure that energy use, carbon emissions and running costs are minimised for a zone 1 space.

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Source: ARC Technical Criteria - 135
Pattern · confidence medium · Imported 2026-09-12, not yet reviewed · next review 2026-12-12
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Citation key: zone-1-mechanically-cooled