Testing and assessment services, with a clear line between independent assessment and testing sold by the company that would perform the remediation.
Indoor air quality testing is the most useful and the most abused service in this directory, and the difference comes down to a single structural question: does the party interpreting the result also sell the remedy?
Legitimate assessment answers a specific question with a method matched to it. Particulate concerns are measured with a calibrated particle counter over a representative period, not with a thirty-second spot reading taken next to a running vacuum. Suspected microbial growth is assessed by visual inspection and moisture mapping first, with surface or air sampling used to confirm a hypothesis rather than to generate one, and results interpreted against an outdoor control sample taken the same day. Combustion safety concerns are answered with a combustion analyser and a worst-case depressurisation test. Carbon dioxide as a proxy for ventilation adequacy is a genuinely useful and cheap measurement that almost nobody offers. Formaldehyde and volatile organic compounds require laboratory analysis of a sampled medium, not a handheld consumer meter with no calibration record.
Abuse in this category takes a consistent form. A free or nearly free air quality test is offered as part of a duct cleaning visit. A device with no published detection method displays an alarming number. The remedy proposed is a service the same technician can perform today at a price agreed on the spot. Nothing about that sequence is measurement; it is a sales close with a prop.
The practical guidance is to prefer assessment that is separately purchased from remediation whenever the stakes justify it, particularly for suspected mould, for health complaints with a medical dimension, and for any real estate transaction. Ask what instrument is being used, when it was last calibrated, what the reference or control is, and what result would cause the assessor to conclude that nothing needs doing. An assessor who cannot describe a negative outcome is not testing.
Where testing is bundled with cleaning, treat it as a screening tool rather than a diagnosis, and require that any finding be shown to you directly, on camera or on the instrument display, rather than described. The filters on this page emphasise certified technicians and verified insurance because in this category, credentials and accountability are the substitute for a result you cannot personally verify.
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