Replace the booth, or fix what is actually broken?

Restore to baseline before judging the booth. A booth cannot be evaluated with loaded media in it, and partial changes hide problems because the airflow path is a series circuit: intake or ceiling media, the cabin, exhaust arrestors, and on heated booths the AMU pre-filters upstream of everything. Replace all of it in one pass, not just the exhaust pads that look ugly. While the banks are open, check what fresh media reveals: crushed filter frames, gaps where pads were stuffed in undersized, daylight through a grid, an exhaust plenum caked in dried overspray. Then have the booth balanced so intake supply and exhaust pull sit at design negative pressure, and record fresh baseline pressure-drop readings across each bank so the restored state is documented.

A worked illustration of the gap between the two spends. Take these as illustrative figures, not quotes. Suppose a full media refresh on a mid-size downdraft, every bank, runs a few hundred dollars in filters plus an afternoon of labor, and a balance and fan service visit adds a few hundred more. Suppose the shop sprays modestly and a disciplined program means four to six full changes a year. That is a four-figure annual airflow budget. A replacement booth project, by the time equipment, demolition, installation, electrical, permitting, and downtime are totaled, is a five-to-six-figure event. The ratio between those numbers is the margin for error: you can fund years of a rigorous filter and maintenance program, with money left for targeted retrofits, before touching the cost of replacement. Any replacement decision made without first spending the small number to restore baseline is a decision made on missing data.

Retrofits that close the gap. If restored airflow still leaves real gaps, most of them have component-level answers. Lighting has dimmed: modern fixtures drop into an existing cabin. Energy cost is the complaint: a variable frequency drive on the fan motors lets the booth idle down between spray cycles instead of running full speed all day, and drive retrofits are a standard, well-understood upgrade on existing booths. Flash times lag: check heat source maintenance and airflow before blaming the cabin. Door seals, gaskets, and control panels are all replaceable parts. Each retrofit competes against replacement on a payback basis, and each one keeps the revenue-producing bay open while it happens.

When replacement genuinely wins. Some problems are not consumable. The cabin is dimensionally wrong for the work you now win, and jobs are being turned away or sprayed half-out the door. The structure is corroded or fire-damaged. The booth's fundamental configuration is wrong for your product mix and no media program changes geometry. Parts for the controls or burner are unobtainable and every failure means improvised repairs. Or the compliance posture is unfixable: a homemade or grandfathered enclosure that cannot meet current fire and electrical code without rebuilding most of it. In those cases replacement is the honest answer, and the same filter discipline applies on day one of the new booth: baseline readings at commissioning, a monitoring cadence, and media purchased on condition.

What this means for filter selection and spend. The decision framework doubles as a purchasing philosophy. A booth kept at baseline by a full-bank, condition-based media program never accumulates the compounding symptoms that make replacement look inevitable. Spec media by the booth's frame sizes and airflow layout, buy the full set rather than cherry-picking the visible pads, and track pressure drop so the change interval reflects your real workload. Cross-referenced fitment from distributor and manufacturer catalogs, verified by the WERCS service team, takes the guesswork out of which sizes and media types your banks actually take; confirm with a fitment check before bulk ordering. The cheapest booth you will ever own is the one you already have, fed correctly.

Compliance cuts both ways in this decision. An existing booth stays compliant with EPA 40 CFR Part 63 Subpart HHHHHH through operational discipline: spraying inside the filtered enclosure, exhaust filter technology meeting the rule's capture efficiency, high transfer efficiency guns, trained painters, and records, all of which a filter and maintenance program delivers without capital. OSHA 29 CFR 1910.94(c) judges the booth on maintained ventilation performance, not on model year; a thirty-year-old cabin with fresh media and documented balance can outperform a new booth run carelessly. Replacement, by contrast, triggers the full current rulebook: construction and fire permits, current NFPA 33 requirements, electrical inspection, and often air permitting review. That is not a reason to avoid replacing a booth that needs it, but it belongs in the replacement column of the cost comparison, and it is a reason the restore-first path is usually the fast one.