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Ravenscroft specialises in providing innovative and energy efficient engineering solutions for the heating and ventilating sector. Our customised engineering solutions yield high quality indoor air while reducing HVAC operating costs.  


Ravenscroft specialises in providing low velocity displacement ventilation solutions to commercial and manufacturing premises.

Thermal displacement ventilation is based on cool air supply at low level and stratification of room air temperature and contaminants as a result of the natural buoyancy forces created by the heat sources. Traditionally the system has been designed as a dedicated outdoor air system.

Solution Types

Ravenscroft supports two alternative concepts used in a displacement ventilation system: horizontal low-velocity supply and floor-mounted diffusers. The extraction point of the exhaust air is located above the occupied zone – preferably close to ceiling level.

A displacement system is preferable for the following situations:

  • the specific airflow rate per unit of floor area is high (as in lobbies, theatres, and conference rooms)
  • high contaminant loads exist, as in industry and smoking areas
  • the height of the space is more than 3 metres 

Halton low velocity unit range covers exposed units and units to be integrated to a wall/column structure. Units can be also covered with a decoration plane. The product range provides excellent indoor climate conditions in terms of air quality, thermal and acoustic conditions especially in high spaces and spaces with high contaminant loads.

As a licenced Halton local manufacturer Ravenscroft is proud to make all Halton low velocity units locally in New Zealand to the same high Halton standards.

displacement diffuser halton ravenscroft

Public Spaces

Application requirements

Architectural considerations place high demands on building service in lobbies, atriums and lounges. The need for demand-based operation is high, as the usage is short-term and the occupancy level varies from crowded to practically empty.

Optimal solution

Halton's displacement ventilation solution for high spaces with variable air flow rates provides the opportunity to manage conditions in spaces with intermittent heat and contaminant loads. Comfortable conditions are achieved efficiently with demand-based control. Low-velocity units' appearance adapts easily to interior architecture.

Halton mixing ventilation with demand-based control can also be applied in ventilation of public spaces to create a good indoor climate with controlled life cycle costs.

More about Displacement Ventilation