What does an oil change on your cooling tower gearboxes really cost, and how fast would purge mist pay for itself? Change any number below. The results update as you type.
The starting values are the four-cell example from The Real Cost of a Cooling Tower Oil Change. They are reasonable Gulf Coast assumptions, not quotes. Replace them with your own work order history and prices for an honest answer.
How the Math Works
- Cost per oil change = oil (gallons × price) + disposal (gallons × rate) + labor (crew × hours × rate) + crane + scaffolding + permits + lost cooling + spill risk (chance × cost) + injury risk (chance × cost).
- Oil changes per year today = gearboxes × changes per gearbox per year. With purge mist = gearboxes ÷ interval in years.
- Failure cost today = failures per year × cost per failure. With purge mist, reduced by the failure reduction percentage.
- Annual savings = total cost today − total cost with purge mist, after adding the cost of oil sampling and mist upkeep.
- Payback = installed cost ÷ annual savings. Net savings = annual savings × years − installed cost.
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Where the Starting Values Come From
- Oil change interval: twice a year without purge mist, once every two to three years with it — Ehlert (2011), Texas A&M Turbomachinery Laboratory
- Oil volume: 10–30 gallons per right-angle drive — Mobil Productivity Pointer: Cooling Towers
- Cost per gearbox failure: about $50,000 — Pennsylvania refinery case, OMLI
- Failure reduction: about 40% fewer failures in purged wet-sump equipment — Oil Mist 101, OMLI
- Cost per injury: $48,000 per medically consulted work injury — National Safety Council, Injury Facts
- All other values are illustrative assumptions. Replace them with your own.
This calculator is an educational screening tool. Results depend entirely on the inputs. Verify with your own cost data and a site assessment before making a decision.