Equipment Replacement vs Repair Cost Calculator

Compare the total cost of repairing existing equipment versus replacing it with new equipment over a defined time horizon, factoring in repair costs, downtime losses, energy efficiency, and residual values.

Existing Equipment (Repair Option)

New Equipment (Replace Option)

Shared Parameters

Formulas Used

Annual Operating Cost = Annual Maintenance + Annual Energy Cost + (Downtime Days × Revenue Lost per Day)

Present Value of Annuity (operating costs over n years at discount rate r):
PV = C × [1 − (1 + r)−n] / r    (if r = 0: PV = C × n)

PV of Single Amount (salvage value at end of horizon):
PV = FV / (1 + r)n

Total NPV of Costs – Repair = Repair Cost + PV(Annual Op Costold) − PV(Salvageold)

Total NPV of Costs – Replace = (Purchase Price + Installation − Incentives) + PV(Annual Op Costnew) − PV(Salvagenew)

Equivalent Annual Cost (EAC) = NPV × r / [1 − (1 + r)−n]
Allows fair comparison of options with different cost structures on a per-year basis.

Simple Payback Period = (Upfrontreplace − Upfrontrepair) / (Annual Op Costold − Annual Op Costnew)

Assumptions & References

  • All costs are expressed in today's dollars; the discount rate reflects the cost of capital or required rate of return.
  • Annual operating costs (maintenance, energy, downtime) are assumed constant over the analysis horizon (annuity model).
  • Downtime loss is calculated as: days of unplanned downtime × daily revenue/profit impact.
  • Salvage/residual values are treated as a single cash inflow at the end of the horizon and discounted accordingly.
  • Incentives and rebates (e.g., utility energy-efficiency rebates) reduce the effective upfront cost of new equipment.
  • The Equivalent Annual Cost (EAC) method is recommended by engineering economics standards (e.g., ASME, ASHRAE) for comparing assets with different lifespans or cost profiles.
  • Energy cost savings from newer, more efficient equipment are a primary driver in hospitality settings (ENERGY STAR® program, U.S. DOE).
  • Reference: Blank & Tarquin, Engineering Economy, 8th ed.; ASHRAE Handbook – HVAC Applications, Chapter on Owning and Operating Costs.
  • This calculator does not account for tax depreciation, financing structures, or inflation adjustments — consult a financial advisor for complex decisions.

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