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

Zone 1 areas must operate energy-efficiently in mechanical cooling and ventilation mode, and in less harsh climates be able to turn the mechanical systems off and work naturally ventilated.

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.

Cooling and dehumidification

Dehumidification ('latent cooling of the air') should be optimised with air cooling ('sensible cooling of the air') if suitable equipment and controls are available.

Why humidity matters this much is set out in what influences thermal comfort. ARC has written down what better-suited equipment would need to do, in an R&D brief for hot humid climates.

Ventilating a room while the air conditioning runs

Ventilation of rooms, for when air conditioning is running, may be:

• a continuous mechanical extract ventilation (MEV) fan - either for individual rooms, or 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 allow.

Air conditioning without ventilation

Air conditioning without adequate room ventilation is strongly discouraged.

Relationship to the other zones

The measures for a zone 1 space sit on top of those for typical zone 2 and zone 3 spaces. The additional measures are those likely to be needed to ensure that energy use, carbon emissions and running costs are minimised.

A zone 1 space still has to work when the power is off - see the three-zone strategy.

Diagram not yet included

The source refers here to diagrams illustrating measures for typical zone 2 and 3 spaces, and then the additional measures needed for a zone 1 space. They have not yet been prepared for the wiki.

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Source: ARC Technical Criteria - Zone 1: Mechanically cooled & ventilated
Pattern · confidence high · Imported 2026-08-29, not yet reviewed · next review 2026-11-29
Tags: zones, cooling, ventilation, air-conditioning
Citation key: zone-1-mechanically-cooled