Write the collector asset, filter family, installed quantity, requested quantity, operating duty, dust and process, airflow or capture requirement, cleaning method, and the decision owner. State whether the buyer is comparing one order, one changeout cycle, a fixed budget period, or another approved horizon. Use the same currency, tax and freight treatment, labor basis, production-cost method, utility boundary, and date basis. If one quote includes freight or hardware and the other does not, normalize the scope or hold it. Do not start with labels such as economy, standard, premium, OEM-equivalent, high efficiency, or extended life; those labels do not provide a measurable comparison boundary.

Confirm each candidate’s family, dimensions, top and bottom or end-cap construction, gasket or seal, retention, support, media, finish or treatment, loading direction, cleaning method, normal and upset conditions, and quantity. Use the dust collector filter RFQ checklist to make the evidence packages comparable. Neither same nominal size nor a higher price proves fit, compatibility, filtration, quality, or service life. If Option A and Option B are not both reviewable against the same requirements, stop the cost comparison and resolve specification evidence first.

For the buyer-selected comparison period, total filter cost equals filter purchase cost, plus changeout labor, plus planned and unplanned downtime cost, plus disposal and cleanup cost, plus attributable fan and compressed-air energy difference, plus documented leakage or quality-event cost. This is a category model, not a universal accounting rule. The buyer chooses which categories are in scope and records the reason for every exclusion. Measured zero, unknown, non-comparable, and excluded are different states. Keep fan energy and compressed-air energy separately supported even though they enter one category. Keep planned and unplanned downtime separate during evidence collection so a scheduled task does not conceal an upset.

Capture unit price, extended price, quantity, freight, tax or duty within the buyer's boundary, required hardware, packaging, quote date, validity, and exceptions. Compare the same delivered scope; do not divide by an unproven service-life claim. A quote evidences commercial cost for its stated scope, not pressure drop, efficiency, fit, construction consistency, useful life, support quality, or compatibility. Compare optional media or treatment as a separate configured candidate. Mark budgetary, expired, conditional, or scope-unclear quotes rather than entering false precision.

Use installation date, removal date, installed quantity, removed quantity, removal reason, condition evidence, duty, process changes, and whether units remain in service. EPA treats replacement parts and replacement labor as recurring cost categories, while its current monitoring page lists particulate outlet concentration or leak indication, pressure differential, temperature, flow, cleaning operation, and fan current as operating indicators. [3] [4] These sources set no universal interval. Compare cohorts only when collector, duty, dust, airflow, cleaning, maintenance, and removal criteria align. Treat still-running filters as censored observations, not completed life; keep supplier estimates as assumptions.

List isolation, access, containment, removal, handling, cleaning, inspection, installation, seal or retention verification, closeout, startup checks, and recordkeeping. Use crew size, role, loaded labor rate, elapsed time, contractor charges, lifting or access equipment, and consumables from actual work orders. OSHA defines the hazardous-energy boundary; it supplies no standard changeout time or labor value. [5] Compare only approved site procedures or a controlled sample task. If one record excludes setup or cleanup, normalize it or hold the labor comparison. Never trade safety steps for a lower model.

For planned downtime, record the scheduled window, production state, shared maintenance, approved allocation, and restart or verification time. For unplanned downtime, record the event, start and return-to-service times, affected line, lost-production or delay method, investigation status, and approved cost owner. An outage during a filter change does not make its entire cost filter-attributable. When production mix, line rate, shared work, or event cause differs between options, mark it non-comparable instead of forcing a per-hour value.

EPA identifies dust disposal as a cost category and says disposal cost is site-specific. [3] Use the buyer’s approved waste route, filter and captured-material classification, container count, containment, transport, disposal invoice, cleanup labor, in-boundary consumables, and reusable-hardware disposition. Do not borrow the chapter’s historical dollar examples. Size, weight, price, or time in service does not automatically determine disposal cost. Different packaging or classification requires current site evidence.

Pressure drop is one part of a fan system, not a savings value. DOE explains that operating point depends on fan and system resistance and that field flow can differ from laboratory conditions. [1] Match airflow or capture requirement, production, fan control, damper, filter seasoning, system configuration, measurement point, hours, and measured power. For pulse cleaning, DOE recommends electrical measurement for more accurate compressed-air energy work. [2] Isolate pulse frequency, compressor loading, pressure, controls, leaks, other demand, and hours. Not attributable or comparable means hold—not zero.

EPA identifies particulate outlet concentration or a bag leak detection system as ways to monitor bag breakage and leakage. [4] Record only a documented event with date, equipment, observed evidence, investigation status, approved cause or allocation, cleanup, rework, scrap, complaint, inspection, replacement, and buyer-approved cost. An observation, alarm, reject, or cleanup does not prove a filter defect or identify the responsible component. Never invent event probability or expected loss. Open, shared, or non-comparable cause keeps the category on hold.

Build an evidence note beside every number: source record, date, quantity, unit, boundary, operating state, attribution method, owner, and status. Convert units only through an approved method and keep original records. A number from another collector, dust, line, production rate, or accounting period is not automatically transferable. Do not silently fill blank fields with zero, average unmatched records, or choose a favorable removal from a mixed population. Run separate scenarios when an assumption is useful, label it assumed, and show how the result changes. A decision remains on hold when a material input is unknown, non-comparable, causally unresolved, or based only on a supplier performance statement.

Every number in this example is illustrative, not a FilterBagWorks test result or savings claim. The example shows why visible holds matter; it does not describe a product, plant, test, service life, or expected result.

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The illustrative partial subtotal differs, but neither option can be ranked because two material categories remain on hold and technical qualification is outside the arithmetic. Completing the model could preserve, reverse, or eliminate the difference. No ROI, payback, savings percentage, or purchasing conclusion follows.