The most accurate method to calculate the hood exhaust airflow is a heat load based design. This method is based on detailed information of the cooking appliances installed under the hood including type of appliance, its dimensions, height of the cooking surface, source of energy and nameplate input power. All this data allows calculating how the particular appliance emits energy into the kitchen. Part of this energy is emitted to the space in the form of the convective plume – hot air rising from the cooking surface. The other part is rejected into the space by radiation warming up the kitchen surfaces and eventually the air in the kitchen.

Halton, using its global kitchen ventilation and air distribution knowledge, has combined the latest technical data to develop a software program that calculates the exact exhaust air requirements based on a heat load design. Each particular cooking appliance is considered together with the room air supply system.