Why compare industrial air-conditioning alternatives by life-cycle cost?
A plant cooling decision often starts after a breakdown, a capacity complaint, or an urgent production-expansion request.
Under that pressure, teams can compare equipment prices while missing electrical upgrades, peak demand, installation disruption, recurring maintenance, failure recovery, production downtime, future renewal, and terminal value.
The least expensive purchase today is not necessarily the least expensive operating decision over ten years.
This calculator compares three owner-operated alternatives on one cooling-load and cost boundary: maintain the current system with planned renewal, expand the existing system, or replace it with a high-efficiency system.
It first applies a usable-capacity rate to rated cooling capacity and warns when an alternative cannot cover the verified peak cooling load.
It then places initial investment, energy and demand cost, preventive maintenance, probability-weighted repair and downtime loss, planned major renewal, cost escalation, discounting, and net residual value into five- and ten-year cash flows.
Engineering question
Can each alternative provide enough usable cooling for the verified peak load?
Cost question
Are equipment, installation, electrical, energy, maintenance, failure, and downtime costs on one boundary?
Approval question
Does the lowest present-value alternative remain credible at five and ten years and under sensitivity cases?
Defaults are not market averages, quotations, or recommended specifications
Every default is a fictional worked example that demonstrates the model.
It is not a benchmark for industrial cooling price, efficiency, service life, failure probability, electricity rates, residual value, discount rate, or acceptable capacity margin.
Replace it with a cooling-load study, twelve months of interval electricity data, applicable equipment submittals, maintenance records, the production plan, and complete like-for-like quotations.
Normalize maintain, expand, and replace boundaries before comparing prices
The name of an alternative matters less than what its technical scope and price include.
A comparison is distorted if a known compressor renewal is omitted from the maintain case while removal, commissioning, and electrical work are fully loaded into the replacement case.
Reclassify every vendor proposal onto a common boundary before entering the values.
Decision boundaries for industrial air-conditioning alternatives| Alternative | Include in scope | Primary risks to verify | What the model tests |
|---|
| Maintain and renew | Existing equipment, compressor or heat-exchanger renewal, controls, service contract, and critical spares | Capacity shortfall, degradation, obsolete parts, and recovery time | Whether low initial spending is outweighed by renewal and expected operating loss |
| Expand the existing system | Additional cooling units, piping, ductwork, pumps, fans, electrical feeds, controls integration, and commissioning | Simultaneous operation, part-load behavior, peak contribution, and controls complexity | When lower investment is overtaken by higher recurring energy and maintenance cost |
| Full high-efficiency replacement | New equipment, removal, foundations, piping, ductwork, electrical service, controls, testing, and transition | Large investment, installation outage, actual part-load performance, and terminal condition | Whether lower energy and failure exposure recover the investment difference |
Rental economics belong in a different comparison
This tool compares owner-operated maintain, expand, and replace alternatives.
It does not model rent, refundable deposits, renewal options, return charges, early-termination fees, or contract buyouts.
Use the commercial HVAC purchase-versus-rental life-cycle cost calculator when the contract form is the decision, and do not count the same cost in both models.
How the calculation works
1) Capacity adequacy
Usable cooling capacity equals rated cooling capacity multiplied by the usable-capacity rate.
Capacity margin equals usable cooling capacity minus verified peak cooling load.
A negative margin activates a warning because a low-cost alternative that cannot serve the load is not independently feasible.
The usable-capacity rate should reflect site temperature, degradation, defrost or shutdown conditions, simultaneous operation, and installed redundancy rather than an arbitrary optimism factor.
2) Electricity and demand contribution
Annual electricity equals rated input power multiplied by annual equivalent operating hours and average load rate.
Year-one energy cost equals that electricity quantity multiplied by the user-entered effective incremental energy price.
Year-one demand cost equals rated input power multiplied by peak coincidence, the monthly incremental demand cost, and twelve months.
This is a planning approximation rather than an hourly simulation, so a site with seasonal rates, time bands, ratchets, or demand controls should validate the result with interval load and billing data.
3) Expected failure and downtime loss
Expected annual repair cost equals annual major-failure probability multiplied by repair cost per failure.
Expected downtime hours equal the same probability multiplied by downtime hours per failure.
Expected production loss equals those expected hours multiplied by contribution margin per downtime hour.
Gross revenue usually overstates the loss because materials, outsourced processing, commissions, and other variable costs may not be incurred during the outage.
Use only unrecovered volume after inventory, alternate lines, overtime recovery, and customer rescheduling are considered.
4) Present value and equivalent annual cost
Energy and demand cost grow with the entered electricity escalation rate.
Maintenance, expected repair, downtime loss, and planned renewal grow with the general cost escalation rate.
Each annual net cost is discounted to the decision date, while net residual value is treated as a credit at the end of the selected horizon.
Equivalent annual cost converts the present value into a level annual amount, which helps teams compare the annual budget burden of differently timed cash flows.
If removal and restoration obligations exceed resale or reuse value, enter a conservative net residual value rather than a gross used-equipment price.
Step-by-step workflow
- Fix one load boundary.
Define the production mix, people, lighting, process heat, ventilation, infiltration, and design outdoor condition included in peak cooling load.
If future production is included, apply the same future condition to all three alternatives.
- Normalize electricity evidence.
Use at least twelve months of bills and interval records to estimate equivalent cooling hours, average load, and contribution during the facility peak.
If production and weather vary substantially by month, perform a separate monthly or hourly cross-check.
- Rebuild each quote on the same scope.
Separate equipment, removal, disposal, installation, piping, ductwork, power, controls, testing, training, warranty, and transition downtime.
Do not treat an omitted item as free without written confirmation of who supplies it.
- Connect maintenance and failure assumptions to records.
Extract comparable major-failure events, parts, contractor labor, response time, and restoration time from the maintenance system.
Adjust each alternative for its warranty, spares strategy, service response, and obsolete-component exposure.
- Review capacity and cost together.
Do not approve the lowest present-value result if its usable capacity is below the load.
Document the investment horizon when the five-year and ten-year rankings differ.
Strengthen the evidence when the preferred alternative changes under energy or failure sensitivity.
- Turn the result into a proposal comparison sheet.
Place load adequacy, warranty, delivery, outage plan, performance test, controls integration, exclusions, and financial results on one approval page.
Use the model to identify questions for engineers and vendors rather than as an automatic purchase instruction.
Reading the fictional default example
The English default is a fictional USD example with a verified peak cooling load of 780 kW and 2,400 equivalent operating hours.
The maintain case provides only 722 kW of usable cooling, so it is 58 kW short before economics are considered.
It also includes a planned renewal in year three and relatively high expected repair and downtime exposure.
The replacement case starts with the largest investment but has lower modeled electricity, maintenance, repair, and downtime cost.
Fictional English default results for industrial air-conditioning life-cycle cost| Alternative | Usable cooling | Year-one recurring cost | Five-year present value | Ten-year present value |
|---|
| Maintain and renew | 722 kW | $196,456 | $1,286,138 | $2,057,217 |
| Expand the existing system | 1,045 kW | $177,836 | $1,075,428 | $1,867,474 |
| ★ Full high-efficiency replacement | 921.5 kW | $107,680 | $969,770 | $1,627,901 |
With those inputs, replacement has the lowest five-year and ten-year present value and is about $239,573 below the next-best ten-year alternative.
The expand-versus-replace cumulative cost, before terminal residual credit, changes direction in year seven.
These values explain the formulas only and do not estimate an actual plant, tariff, proposal, or product.
The maintain case remains technically short of capacity even if another financial assumption temporarily moves it up the cost ranking.
Practical decision scenarios
Urgent review after a major failure
Do not compare repair cost with replacement price alone.
Include the probability and duration of another major failure, planned renewal, current capacity shortfall, and any temporary rental or emergency work without double counting.
Cooling infrastructure for production expansion
Set the future production peak load first, then compare usable capacity for expansion and replacement.
Include incoming power, switchgear, piping, ductwork, controls integration, and commissioning to expose enabling work.
Normalization of several vendor proposals
Reclassify different ratings, operating conditions, part-load claims, installation scopes, warranties, and service periods into the same fields.
Mark unanswered scope as unresolved instead of assuming a zero cost.
Energy-saving investment approval
Build savings from input power, operating hours, average load, and peak coincidence rather than one unsupported percentage.
Check whether energy-up and energy-down cases preserve the ranking.
Budgeting for an aging retained system
Place the expected renewal year, preventive maintenance, recovery cost, downtime, and terminal condition into the budget.
Use the annual cash-flow table to find a renewal followed too quickly by a replacement.
Cross-functional downtime review
Have production, maintenance, and finance agree on one major-failure event and hourly contribution definition.
Reflect only demand that inventory, alternate lines, rescheduling, or recovery shifts cannot serve.
Evidence checklist before entering values
- Load and performance: Prepare a cooling-load study for the relevant production condition, outdoor design condition, equipment submittals, rated cooling and power, and applicable part-load evidence.
- Electricity: Prepare twelve months of bills, interval maximum-demand data, the applicable service classification, voltage, rate option, and cooling operating logs.
- Maintenance: Prepare preventive service contracts, work orders, parts and contractor invoices, response times, restoration times, and long-lead spare information.
- Production: Prepare bottleneck output during the outage window, contribution per unit, inventory protection, alternate-line capacity, and feasible recovery production.
- Proposal scope: Prepare line-item equipment, removal, disposal, installation, piping, ductwork, electrical, controls, testing, training, warranty, delivery, and exclusions.
- Finance: Prepare the approved discount rate, escalation assumptions, decision horizon, and net residual value after expected removal or restoration cost.
Do not generalize an efficiency label beyond its product scope
Korea Energy Agency efficiency and high-efficiency programs have product-specific applicability and technical criteria.
Do not assume every industrial or special-purpose cooling system carries the same label or certification.
Verify whether the exact model is within an applicable program and use its official record, tested data, manufacturer submittal, or site measurement for cooling capacity and input power.
Official-source boundaries used by the model
The publication status and applicability boundaries below were reviewed on August 15, 2026.
They define method and evidence boundaries rather than supplying the fictional input values.
NIST life-cycle costing structure
The model uses the time-phased cost, present-value, replacement, and residual-value structure described by the official NIST Handbook 135e2022 publication page as a methodological boundary.
NIST does not supply the plant-specific price, useful life, failure probability, Korean electricity rate, or corporate discount rate entered here.
Interpretation limits and approval controls
What the calculator does not decide
- Cooling-load design, redundancy, or equipment selection.
- Electrical service, protection, harmonics, or interconnection adequacy.
- Refrigerant, environmental, safety, fire, structural, or permit compliance.
- Vendor capability, warranty enforceability, commissioning acceptance, or contract suitability.
- Tax, depreciation, grants, insurance, financing, or accounting treatment.
Controls for an approval package
- Attach the load study revision and the production scenario it supports.
- Attach normalized quotation sheets and a list of unresolved exclusions.
- Identify each operating assumption by meter, submittal, work-order, pilot, or owner estimate.
- State the discount and escalation approval owner and review date.
- Record capacity warnings and sensitivity cases beside the financial ranking.
Frequently asked questions
Are rated cooling capacity and rated input power enough?
No.
You also need usable capacity at the site condition, part-load behavior, operating hours, and peak coincidence.
Ratings can screen options, but procurement should use a load study and selection data for the actual condition.
Can an efficiency label be converted directly into annual savings?
Not reliably.
First verify that the exact equipment is within the applicable program scope, then compare cooling and input power at comparable conditions.
Do not turn one label into a whole-system annual savings percentage.
Which electricity price should I enter?
Use an effective incremental energy price based on the applicable service class, voltage, option, season, time band, and site pattern.
Enter only the cooling alternative contribution to monthly peak cost rather than duplicating the entire facility bill.
Does a thirty-five-percent failure probability mean exactly 0.35 failures every year?
The model converts an annual probability into an expected planning cost.
A real year may have no event or one severe event, so expected value does not replace spares, contingency, insurance, or continuity planning.
What happens when renewal is scheduled in the terminal year?
Terminal residual value should already represent equipment condition at that date, so the model does not add a separate renewal in the same terminal year.
If renewal is unavoidable immediately before the horizon ends, adjust timing and residual assumptions without counting the same value twice.
What does the expand-versus-replace crossover year mean?
It is the first year when their cumulative present-value difference, before terminal residual credit, changes direction.
It is not automatically the optimal replacement date because capacity, outage windows, failure exposure, and implementation readiness still matter.
Should downtime loss use revenue?
Usually not.
Apply contribution margin to demand that cannot be recovered through inventory, alternate lines, customer rescheduling, or later production.
Avoid counting materials and other variable costs that the outage prevents.
Does the calculator recommend the cheapest vendor?
No.
It compares the cash flows created by user-entered technical and cost assumptions.
It does not assess or recommend a manufacturer, model, contractor, safety design, performance guarantee, or contract.
Bring the load sheet and complete quotes into one decision model
Start with the verified peak cooling load and interval electricity evidence, then enter maintain, expand, and replace assumptions on their separate tabs.
Review capacity warnings, five- and ten-year present value, cost composition, annual cash flow, and sensitivity with engineering, production, maintenance, procurement, and finance.
Use the result to frame the next load-review, site-survey, performance-test, and vendor-question actions before approval.