Running a filter to the final manufacturer’s recommended pressure reading could mean you are squeezing every last penny of cost from the filter. It could also mean you just wasted more money in energy costs because of the extra time it takes to heat or cool your facility due to lower supply velocities. So how do you know when it is the optimal time to change your filters?
The following equation will apply:
Energy Cost = HP x ($/KwHr) x Hours/0.746
Where HP (motor horsepower) = Average DP x CFM/Fan Efficiency x 0.001173
This is graphically represented by:
By utilizing this formula, you can determine where the optimal change out time is for your particular filtration system based on your specific electric rates, hours of operation and type of filter.
1NAFA Guide to Air Filtration, 3rd Edition 2001, National Air Filtration Association, page 13.2- 13.6