INDR 202
ENGINEERING ECONOMICS
CHAPTER 12
REPLACEMENT DECISIONS
SPRING 2015
REPLACEMENT DECISIONS
REPLACEMENT ANALYSIS
REPLACEMENT DECISION
replacement of existing obsolete/worn-out assets
DEFENDER
existing equipment
CHALLENGER
best available replacement equipment
CURRENT MARKET VALUE of defender
TRADE-IN ALLOWANCE offered by vendor to reduce the price of new equipment
EXAMPLE 1: SUNK COSTS
$0 $10,000 $20,000 $25,000 SUNK COSTS $15,000
ORIGINAL INVESTMENT $20,000
MARKET VALUE
$10,000
LOST INVESTMENT
$10,000
REPAIR COST
REPLACEMENT ANALYSIS
CASH-FLOW APPROACH
proceeds from sale of the defender as down payment toward purchasing the challenger
(equal analysis period for all alternatives)
OPPORTUNITY-COST APPROACH
proceeds from sale of the defender as investment required to keep the defender
EXAMPLE 1: CASH-FLOW APPROACH
0 1 2 3
$8,000
$2,500
DEFENDER
0 1 2 3
$6,000
$5,500
CHALLENGER
$15,000
$10,000 sales proceeds
EXAMPLE 1: CASH-FLOW APPROACH
DEFENDER
𝐴𝐸# 12% = $2,500 𝐴|𝐹, 12%, 3 − $8,000 = −$7,259.10
CHALLENGER
𝐴𝐸4 12% = $5,500 𝐴|𝐹, 12%, 3 − $6,000 − $5,000 𝐴|𝑃, 12%, 3
= −$6,451.79
EXAMPLE 1: OPPORTUNITY-COST APPROACH
0 1 2 3
$8,000
$2,500
DEFENDER
0 1 2 3
$6,000
$5,500
CHALLENGER
$15,000
$10,000
EXAMPLE 1: OPPORTUNITY-COST APPROACH
DEFENDER
𝐴𝐸# 12% = $2,500 𝐴|𝐹, 12%, 3 − $8,000 − $10,000 𝐴|𝑃, 12%, 3
= −$11,422.64
CHALLENGER
𝐴𝐸4 12% = $5,500 𝐴|𝐹, 12%, 3 − $6,000 − $15,000 𝐴|𝑃, 12%, 3
= −$10,615.33
ECONOMIC SERVICE LIFE
ECONOMIC SERVICE LIFE
useful life of a defender (or a challenger) that results in the minimum annual equivalent cost (ownership & operating)
ECONOMIC SERVICE LIFE
CAPITAL COST
𝐶𝑅 𝑖 = 𝐼 𝐴|𝑃, 𝑖, 𝑁 − 𝑆
?𝐴|𝐹, 𝑖, 𝑁
= 𝐼 − 𝑆
?𝐴|𝑃, 𝑖, 𝑁 + 𝑖𝑆
?OPERATING COSTS
𝑂𝐶 𝑖 = B 𝑂𝐶
C𝑃|𝐹, 𝑖, 𝑛
?
CEF
𝐴|𝑃, 𝑖, 𝑁
TOTAL COST
ECONOMIC SERVICE LIFE
Useful Life
EXAMPLE 2: ECONOMIC SERVICE LIFE
Initial cost: $18,000
Operating costs: $1,000 in year 1 & 15% annual increase
Salvage value: $10,000 in year 1 & 25% annual decrease
Maximum life: 7 years
EXAMPLE 2: ECONOMIC SERVICE LIFE
𝑁 = 1
EXAMPLE 2: ECONOMIC SERVICE LIFE
𝑁 = 2
𝐴𝐸𝐶H 15% = $18,000 + $1,000 𝑃|𝐴F, 15%, 15%, 2 𝐴|𝑃, 15%, 2
EXAMPLE 2: ECONOMIC SERVICE LIFE
Minimum Cost
Economic Service Life
𝑁 = 6
𝑁 𝐴𝐸𝐶? 15%
INDEFINITE SERVICE PERIOD
REPLACE DEFENDER NOW
Challenger cash flows occur for an infinite number of years starting now.
Challenger is replaced by an identical one if necessary.
REPLACE DEFENDER
𝒙
YEARS LATER
Defender cash flows occur in the first 𝑥 years.
EXAMPLE 3: INDEFINITE SERVICE PERIOD
REPLACE DEFENDER NOW
New machine cost: $10,000.
Operating cost: $2,200 in year 1 with 20% annual increase Salvage value: $6,000 in year 1 with 15% annual decrease
REPLACE DEFENDER
𝒙
YEARS LATER
Repair cost to use broken machine for 5 years: $1,200.
Operating cost: $2,000 in year 1 with $1,500 annual increase Salvage value: $5,000 now with 25% annual decrease
EXAMPLE 3: INDEFINITE SERVICE PERIOD
𝑁 = 1
:
𝐴𝐸𝐶
F15% = $5,380
𝑁 = 2
:
𝐴𝐸𝐶
H15% = $5,203
𝑁 = 3
:
𝐴𝐸𝐶
K15% = $5,469
𝑁 = 4
:
𝐴𝐸𝐶
L15% = $5,844
𝑁 = 5
:
𝐴𝐸𝐶
M15% = $6,258
Remaining Useful (Economic) Service Life of Defender
Minimum Cost
EXAMPLE 3: INDEFINITE SERVICE PERIOD
𝑁 = 1
:
𝐴𝐸𝐶
F15% = $7,700
𝑁 = 2
:
𝐴𝐸𝐶
H15% = $6,184
𝑁 = 3
:
𝐴𝐸𝐶
K15% = $5,756
𝑁 = 4
:
𝐴𝐸𝐶
L15% = $5,625
𝑁 = 5
:
𝐴𝐸𝐶
M15% = $5,631
Economic Service Life of Challenger
Minimum Cost
EXAMPLE 3: INDEFINITE SERVICE PERIOD
CHALLENGER
𝑁
4= 4
𝐴𝐸𝐶
415% = $5,625
DEFENDER
𝑁
#= 2
𝐴𝐸𝐶
#15% = $5,203
To replace the defender now?
NO: 𝐴𝐸𝐶# 15% < 𝐴𝐸𝐶4 15% , keep it by
EXAMPLE 3: MARGINAL ANALYSIS
Incremental cost of keeping defender one more year from the end of its economic service life:
Opportunity cost at the end of year 2: $2,813 Operating cost in year 3: $5,000
Salvage value at the end of year 3: $2,109
STEP 1. Equivalent cost of keeping the defender in year 3
$2,813 𝐹|𝑃, 15%, 1 + $5,000 − $2,109 = $6,126
STEP 2. 𝐴𝐸𝐶4 15% = $5,625 < $6,126
TAX CONSIDERATIONS
Whenever possible, after-tax cash flows should be used
in replacement analysis.
EXAMPLE 1: TAX CONSIDERATIONS
MARKET VALUE $10,000
TAX CREDIT
$4,693 40% = $1,877
NET PROCEEDS FROM DISPOSAL $11,877
$0 $10,000 $14,693 $20,000 DEPRECIATION
$5,307
$4,693 BOOK LOSS
MARKET VALUE $10,000
DEPRECIATION COST BASIS $20,000
EXAMPLE 3: TAX CONSIDERATIONS
REPLACE DEFENDER NOW
New machine cost: $10,000.
Operating cost: $2,000 in year 1 with $1,000 annual increase Salvage value: $6,000 in year 1 with 15% annual decrease
REPLACE DEFENDER
𝒙
YEARS LATER
Repair cost to use broken machine for 5 years: $1,200.
Operating cost: $2,000 in year 1 with $1,500 annual increase Salvage value: $5,000 now with $1,000 annual decrease
EXAMPLE 3: TAX CONSIDERATIONS
Year Current Market Value After-Tax Salvage Value
0 $5,000 $5,000(60%) = $3,000 1 $4,000 $4,000(60%) = $2,400 2 $3,000 $3,000(60%) = $1,800
3 $2,000 $2,000(60%) = $1,200
4 $1,000 $1,000(60%) = $600
5 $0 $0
6 $0 $0
EXAMPLE 3: TAX CONSIDERATIONS
DEFENDER
Year Overhaul Operating Cost After-Tax Operating Cost
0 $1,200 $1,200(60%) = $720
DEFENDER
𝑁 = 1
𝑁 = 2
𝑁 = 3
𝑁 = 4
EXAMPLE 3: TAX CONSIDERATIONS
EXAMPLE 3: TAX CONSIDERATIONS
Annual Equivalent Cost
SUMMARY
In replacement analysis,
defender
is an existing asset &
challenger
is the best available replacement candidate.
Current market value
is the value to be used in economic
analysis of a defender.
Sunk costs
cannot be changed by future decisions, so are
not considered in replacement analysis.
Two basic approaches to replacement problems are:
§ cash-flow approach, explicitly considering actual cash flow
consequences for replacement alternatives as they occur,
§ opportunity-cost approach, viewing proceeds from the sale