Products

Choosing a fan - what you need to know

The fan is the main component of a ventilation system: it supplies, extracts or circulates air. To choose the right fan you need to know the required airflow, the resistance (pressure) of the system, the permitted noise level, the operating temperature and the purpose of the building.

In the NB Group catalogue fans are grouped by type, according to the task they are built for:

• Duct fans - installed inside ductwork, for supply or extraction;
• Axial fans - high airflow, low resistance;
• Radial (centrifugal) fans - for high-pressure systems;
• Roof fans - air extraction through the roof of the building;
• EC fans - energy-efficient, variable speed;
• High-temperature fans - for hot air;
• Explosion-proof fans - special models for hazardous environments;
• Bathroom fans - for humidity control.

What is an exhaust fan?

An exhaust fan removes used air, odours, humidity, grease or other fumes from a space. An exhaust system is particularly important in kitchens, production facilities, warehouses and commercial premises.

Depending on the application, an exhaust system can use a duct, roof or radial fan. In a kitchen exhaust system the air temperature, grease content and resistance of the exhaust duct also matter, so not every fan is automatically suitable. For industrial exhaust the deciding factors are the continuous removal of large air volumes and the conditions of the working environment.

Types of exhaust fan

Exhaust fans come in several constructions, each intended for a different kind of building. In the NB Group catalogue the exhaust models are found in the following categories:

• Duct exhaust fans - mounted in the ductwork; the kitchen exhaust models (BKEF series, BHV-P) are built for greasy, high-temperature air.
• Roof exhaust fans - installed on the roof, discharging air straight outside through a vertical duct.
• Axial exhaust fans - wall or window mounted, high airflow at low resistance.
• Industrial exhaust - radial fans - high pressure for long duct runs and industrial exhaust systems.
• Bathroom exhaust fans - compact, low-noise models for wet rooms.
• Explosion-proof exhaust fans - for ATEX environments where flammable gases or dust accumulate.

If you are not sure which type you need, the selection criteria below will help, or contact us for a consultation.

How to choose the right fan

A fan should not be chosen on size or maximum m³/h alone. The main parameters are:

• required airflow (m³/h) - based on the room volume and air change rate;
• system resistance - taking ducts, bends, grilles and filters into account;
• pressure capability - a radial fan is better for a complex duct network;
• noise level - critical in offices and residential spaces;
• operating temperature and environment.

For the system to work properly the fan is used together with air diffusers, grilles, dampers and filters, and for installation - profiles, mounting accessories and insulation.

Ventilation, heating and energy efficiency

In a modern HVAC system ventilation is not only about moving air - using energy efficiently matters too. Heat recovery units use part of the heat in the outgoing air to warm the incoming fresh air, heat-efficient units reduce energy loss, while air heaters and air curtains heat the space and control the temperature at entrances.

NB Group - brands and delivery

NB Group is the official representative of the BVN, Makro Teknik and Sonniger brands in Georgia. The company has branches in Tbilisi and Batumi, and products can be delivered to other regions of Georgia. Technical consultation is available to help select the right system.