Equipment Costs
Learning Objectives
- Differentiate between equipment ownership costs and operating costs.
- Describe various methods for calculating equipment depreciation.
- Explain how to calculate a total hourly rate for heavy equipment.
- Understand how to calculate equipment cycle times and production rates.
- Apply efficiency factors to determine actual, real-world equipment production.
Equipment costs represent a massive capital investment for construction firms, particularly for large, heavy-civil projects involving earthwork, paving, or mass concrete placement. Unlike labor or materials, which are generally incurred only when work is actively progressing, certain equipment costs (like loan interest, property taxes, and insurance) persist even when the machinery sits idle in the contractor's yard. Accurately allocating these costs into an hourly rate is critical for competitive bidding.
Ownership Costs vs. Operating Costs
Categories of Equipment Costs
The total hourly cost to run a piece of equipment is calculated by adding its fixed ownership cost per hour to its variable operating cost per hour.
Total Hourly Equipment Rate
Calculates the comprehensive hourly cost of operating heavy machinery.
Variables
| Symbol | Description | Unit |
|---|---|---|
| The overall cost charged to the project per hour of equipment use | Currency/Hour | |
| The fixed hourly cost including depreciation, interest, and insurance | Currency/Hour | |
| The variable hourly cost including fuel, maintenance, and wear parts | Currency/Hour |
Ownership Costs
Ownership costs are incurred simply by possessing the asset. Key components include:
Components of Equipment Ownership Costs
- Depreciation: The decline in market value or salvage value over the machine's useful life due to age, wear, tear, and technological obsolescence. This is almost always the largest single component of ownership cost.
- Interest (Investment Cost): The cost of borrowing money from a bank to purchase the equipment, or conversely, the opportunity cost of tying up the company's own capital in a machine that could be invested elsewhere for a return.
- Taxes, Insurance, and Storage (TIS): Annual recurring overhead costs. This includes local property taxes assessed on the asset's value, insurance premiums protecting against fire, theft, or damage, and the overhead cost of securing and storing the equipment in a yard when it is not deployed on a project. These are typically expressed as a percentage of the average annual investment.
Operating Costs
Operating costs vary directly with the equipment's workload, the harshness of the site conditions, and the actual hours of use. Key components include:
Components of Equipment Operating Costs
- Fuel: Diesel or gasoline consumption. This varies heavily depending on the engine size and whether the machine is idling, doing light work, or performing heavy digging.
- Lubricants and Filters: Required for routine preventative maintenance (engine oil, hydraulic fluid, grease, air and fuel filters). It is often estimated as a flat percentage of the fuel cost.
- Tires or Tracks: Significant, highly expensive wear parts. High-impact operations on sharp rock severely shorten tire life. Track replacement on dozers or excavators is a major, recurring expense that must be accrued hourly.
- Repairs and Maintenance: Costs for routine servicing (mechanic's labor), replacement of minor parts, and major overhauls (engine rebuilds) required to keep the equipment operational throughout its entire useful life.
- Operator Wages: The labor cost of the individual running the machine. While this is technically an operating cost of the machine, estimators frequently separate operator wages into the "Labor" column of the estimate to accurately track total project man-hours, adding only the physical machine costs to the "Equipment" column.
Depreciation Methods
Depreciation
An accounting method for allocating the capital cost of a tangible asset over its useful life. It mathematically represents how much of an asset's original value has been consumed by wear and tear or age.
Two common methods for calculating depreciation in engineering economy and construction estimating are:
Common Equipment Depreciation Methods
- Straight-Line (SL) Depreciation: The simplest and most widely used method for estimating internal hourly rates. It assumes the asset loses an equal, uniform amount of value each year of its useful life.
- Declining Balance (DB) Depreciation: An accelerated method where the asset loses a larger percentage of its value in its early years and progressively less in later years. This often more accurately reflects true market resale value drops (like driving a new car off the lot), but is more complex to use for flat hourly estimating rates.
Interactive Simulation
Explore the interactive simulation below to visualize how different parameters affect equipment costs over time.
Straight-Line Depreciation Simulator
Visualize how the book value of construction equipment declines over its useful life using the straight-line depreciation method.
Asset Details
Book Value Over Time
Mathematical Methods of Depreciation
Equipment estimators must convert the total depreciation of an asset over its entire life into an hourly cost to be charged to the project. The IRS requires specific methods for tax purposes, but estimators use variations to determine internal billing rates.
Detailed Depreciation Methods Overview
- Straight Line Depreciation (SLD): The simplest method. It assumes an asset loses value equally every year of its useful life. The annual depreciation is the initial cost minus the salvage value, divided by the number of years.
- Declining Balance Method (DB): An accelerated depreciation method. The asset depreciates more in its early years than in its later years, which often matches reality (like driving a new car off the lot). A common version is the Double Declining Balance (DDB).
- Sum-of-the-Years'-Digits (SYD): Another accelerated method based on a fraction where the denominator is the sum of the digits of the useful life (e.g., for a 5-year life, ). In year one, of the value is depreciated, in year two, , and so on.
- Modified Accelerated Cost Recovery System (MACRS): The standard system required by the US IRS for tax depreciation. While estimators don't usually use MACRS directly to set internal hourly rates, they must understand it because it heavily influences a company's cash flow and decision on when to buy vs. rent new equipment.
Straight Line Depreciation Formula
Calculating the equal annual loss in value over the equipment's lifespan.
Straight Line Depreciation Formula
Calculates the equal annual loss in value over the equipment's lifespan.
Variables
| Symbol | Description | Unit |
|---|---|---|
| Annual depreciation cost | Currency/Year | |
| Initial purchase price of the equipment | Currency | |
| Estimated salvage or resale value at the end of its useful life | Currency | |
| Useful life of the equipment | Years |
Equipment Cycle Times & Production Rates
To accurately estimate total equipment costs, the estimator must not only know the hourly cost but also the total time required. The total time depends entirely on the equipment's production rate. Production rate calculations begin with analyzing a single machine cycle.
Cycle Time Components
A "cycle" is one complete iteration of a repetitive task (e.g., an excavator digging a scoop of dirt, swinging, dumping into a truck, and swinging back). Cycle time consists of fixed and variable components:
Cycle Time Components Breakdown
- Fixed Time: Operations that take roughly the same amount of time regardless of haul distance (e.g., loading the bucket, dumping, accelerating, braking, and maneuvering).
- Variable Time (Haul and Return): Operations that depend strictly on the travel distance and travel speed (e.g., a dump truck driving from the cut site to the fill site and back). Travel time is calculated as .
Cycle Time Formula
Total Cycle Time Formula
Determines the total duration required for one complete cycle of a machine's operation.
Variables
| Symbol | Description | Unit |
|---|---|---|
| The sum of all fixed and variable time components for one cycle | Minutes (or Seconds) | |
| Time required for constant operations like loading and dumping | Minutes (or Seconds) | |
| Time required for travel, dependent on distance and speed | Minutes (or Seconds) |
Production Rate Calculation
Once cycle time is known, the estimator can calculate the ideal unadjusted production rate (e.g., loose cubic meters per hour). The estimator must then apply an efficiency factor to reflect reality (a 60-minute hour is rarely 100% productive due to short breaks, maneuvering delays, and human error; a typical efficiency factor is 45 to 50 minutes per hour, or 75% to 83% efficiency).
Production Rate Calculation Steps
- Determine Cycles per Hour: Divide 60 minutes by the Total Cycle Time (in minutes).
- Determine Payload per Cycle: Find the bucket or truck bed capacity (in loose measure).
- Calculate Ideal Hourly Production: Multiply Cycles per Hour by the Payload.
- Calculate Actual Production Rate: Multiply the Ideal Hourly Production by the Efficiency Factor (e.g., 50 min/hour 60 min/hour = 0.83).
Actual Production Rate Formula
Calculates the real-world output of machinery by factoring in operational efficiency.
Variables
| Symbol | Description | Unit |
|---|---|---|
| The realistic volume of work completed per hour | Volume/Hour (e.g., m³/hr) | |
| The duration of one complete machine cycle | Minutes | |
| The capacity of material moved per cycle | Volume (e.g., m³) | |
| A decimal representing productive time per hour (e.g., 50 min/hour = 0.83) | Unitless |
By dividing the total quantity takeoff (e.g., 5,000 of soil) by the actual production rate (e.g., 100 /hr), the estimator determines the total equipment hours required (50 hours). Multiplying those 50 hours by the total hourly equipment rate calculated previously yields the final estimated equipment cost.
- Equipment costs are systematically divided into fixed ownership costs (depreciation, interest, insurance, taxes) and variable operating costs (fuel, lubricants, repairs, tires).
- Ownership costs accrue continuously, even when idle. Operating costs only accrue when the key is turned.
- The total hourly rate used in estimating is the sum of the hourly ownership cost and the hourly operating cost.
- Depreciation accounts for the declining value of heavy equipment over its useful life and is usually the largest component of ownership cost.
- Straight-line depreciation is the simplest method, allocating the purchase cost evenly over the asset's life, making it easy to convert to an hourly estimating rate.
- Accurate equipment estimating requires understanding not just the purchase price, but the total lifecycle cost including intense maintenance, fuel consumption, and final salvage value.
- Equipment costs are completely driven by production rates.
- Cycle time consists of fixed (loading/dumping) and variable (travel) components.
- Estimators must always adjust ideal, theoretical production rates downward by applying a realistic efficiency factor to account for unavoidable real-world delays.