The calculation below is based on an actual lab and actual utility cost.

Calculation 1 assumes that the Fume Cupboard will operate 24hrs per day 365 days a year and does not take into account any holidays or shut down periods – this is therefore the maximum cost for running a 1800 mm wide Fume Cupboard based on local utility costs.

Calculation 2 assumes that the Fume Cupboard is fitted with our Greenenergy VAV controls that will reduce the extract volume from the fume cupboard by 85% when the sash is closed. For the calculation we have assumed that the sash will remain open during normal working hours (8.00am to 6.00pm) and will be closed at all other times. We have assumed that the air supply will track the extraction volume from the fume cupboard – i.e. air supply will be reduced by 85% when the sash is closed.

Calculation 3 assumes that we have Greenenergy VAV controls on the fume cupboard and air supply to the laboratory and that the fume cupboard is fitted with an automatic sash closer that will close the sash when the operator is not present at the fume cupboard. For the calculations we have, therefore, assumed that the fume cupboard will be open to 500mm at full volume for 2 hours per day.

Energy Calculations – Typical 1800mm Fume Cupboard (Manchester Area) 2010