A single-suction-point system in a basement or slab home is usually a one-day install. Crawl spaces that need a membrane, and houses with two foundation types, can take longer. The follow-up test then runs at least 48 hours.
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The install day is only the middle of the sequence. Before it, Ohio's mitigation standards call for a visual inspection, a floor plan sketch, and a communication test wherever the material under the slab is unknown, so the suction point is chosen from data rather than habit. After it, the post-mitigation test has to begin no sooner than 24 hours and no later than 30 days after the fan is switched on, run by the specialist who installed the system or by an independent Ohio-licensed tester. Weather can nudge the calendar too: Ohio's testing rules bar short tests during severe storms or sustained winds of 30 mph or more, which can push a retest by a day or two in a blustery March. If a closing date is driving the schedule, say so on the first call and the plan gets built backward from it.