Who should I call to test my indoor air quality?

Who to call depends on what you are worried about, because "indoor air quality" is not one test. Radon, mold, humidity, carbon monoxide and chemical fumes are each measured differently, and some have no official limit to measure against. Use the guide below to match the problem to the right person, and do the cheap screening yourself first.

Radon: a certified radon tester (or a kit)

Radon testing has its own rule in Virginia law. Under Va. Code § 32.1-229.01, "No person shall conduct or offer to conduct any radon screening, testing, or mitigation in the Commonwealth unless he (i) is listed as a professional by either the National Radon Proficiency Program or the National Radon Safety Board"^[1] or meets another measure the EPA or the Board of Health accepts.^[1] The Virginia Department of Health says certification means taking an approved training course, passing a proctored exam and applying to one of the two organizations, with renewal every two years,^[4] and both lists can be searched by ZIP code.^[2]

You do not need a professional to screen your own home. VDH says you may hire one, especially if you are buying or selling a home.^[2] For a do-it-yourself short-term test, VDH lists the key conditions as 12 hours of closed-house conditions before and during the test, a minimum 48-hour test period, the lowest occupied level, and a spot at least 20 inches off the floor.^[3]

What it costs. When we checked on 26 October 2026, VDH's testing page said a professional radon test will usually cost between $100-200, depending on the test device used.^[2] Fixing a high result costs more. When we checked on 26 October 2026, VDH's testing page (last updated October 22, 2026) put a typical sub-slab system at $800-1200, with crawl spaces or homes with several sections needing mitigation at $2000 or more,^[2] and its FAQ page (last updated December 17, 2025) said a professionally installed radon reduction system typically ranges from $800 to $2,500.^[3]

Reading the result. Four picocuries per liter of air has been identified by EPA as the recommended action level.^[3] A first result between 4.0 and 9.9 calls for a long-term follow-up test; if the first test was 10.0 pCi/l or above, a second test of short term duration should be taken.^[3] If you do need mitigation, VDH says that in most cases, elevated radon levels can be reduced below 2 pCi/l.^[3]

Stale air, humidity, dust and odd airflow: a licensed HVAC contractor

When the air feels heavy, humidity stays high, rooms are uneven or the vents blow dust, the heating and cooling system is the place to start. An HVAC technician can check the filter and blower, measure humidity, look at the ducts and drain pan, and tell you whether fresh-air ventilation or a dehumidifier makes sense. In Virginia, the Board for Contractors regulates individual tradesmen in heating, ventilation and air conditioning (HVAC),^[12] so check the business on DPOR's License Lookup before the visit.

The same contractor, or the company that supplies your fuel, handles combustion appliances. If you suspect a furnace, water heater or other fuel-burning appliance, the EPA says to contact qualified appliance service people to have your appliances inspected and adjusted if needed,^[10] and notes that in some areas, the local fuel company may be able to inspect and adjust the appliance.^[10] A battery or plug-in carbon monoxide alarm certified to the current UL 2034 standard^[9] is your own early warning in the meantime; a hard-wired one is a job for a licensed electrician.

Mold: usually no test, sometimes an experienced pro

If you can see it, you probably do not need a test. The EPA says in most cases, if visible mold growth is present, sampling is unnecessary,^[5] and because no EPA or other federal limits have been set for mold or mold spores,^[5] a lab result cannot tell you whether a house "passes."

Where testing does make sense, the EPA's standard is high: "Sampling for mold should be conducted by professionals who have specific experience in designing mold sampling protocols, sampling methods, and interpreting results."^[5] Suspect hidden mold if a building smells moldy but you cannot see the source, or if you know there has been water damage and people in the house are reporting health problems.^[5] In that case, the EPA's advice is direct: If you believe that you may have a hidden mold problem, consider hiring an experienced professional.^[5]

Duct cleaners: be careful what you are sold

Duct cleaning companies often pitch air testing. The EPA's guidance is to ask the service provider to show you any mold they say exists,^[6] to talk to at least three different service providers and get written estimates,^[6] and to remember that EPA neither establishes duct cleaning standards nor certifies, endorses, or approves duct cleaning companies.^[6] It also warns: "Do not hire duct cleaners who make sweeping claims about the health benefits of duct cleaning".^[6]

Chemical smells: start with the source

No federally enforceable standards have been set for VOCs in non-industrial settings,^[8] so a general "chemical test" rarely changes what you do. One exception is formaldehyde, which the EPA calls one of the few indoor air pollutants that can be readily measured.^[8] For new-paint, new-furniture or stored-chemical smells, removing the source and airing the house out usually does more than a test. See how to improve indoor air quality at home.

Clues that help whoever you call

The EPA points out that symptoms from indoor air often look like a cold, so time and place matter: If the symptoms fade or go away when a person is away from the area,^[7] look for a source in that area. Write down when it happens, which rooms, and what was running.

Stop and call a pro if

• A CO alarm sounds or several people feel unwell at once. The EPA says to get fresh air immediately, open windows and doors, turn off any combustion appliances and leave the house,^[10] then call for help and have the appliances checked.
• You smell gas. Columbia Gas of Virginia says a sulfur or rotten-egg-like odor could mean a gas leak: get out immediately, do not use anything that could cause a spark, like a phone, light switch, appliance or flashlight, and call 911 and your gas company from a safe location away from the building.^[11] An air test is not the answer to a gas smell.
• Your radon screening comes back at 4 pCi/L or higher. Book the follow-up test, then a certified mitigator.
• You see mold over more than a small area, or smell it with no visible source. Call an experienced mold professional.
• Someone's health seems to track the house. The EPA says if family members are experiencing unusual or unexplained symptoms or illnesses that you think might be related to your home environment, you should discuss the situation with your doctor.^[6]

Finding the right business

Loclis lists DPOR-licensed businesses with their licence number and class. Browse radon testing, mold testing and indoor air quality services, look up HVAC businesses in Blacksburg, or read all heating and cooling answers. If the house simply feels heavy, start with why a house feels stuffy.

If the problem points to your heating and cooling system, describe it once and licensed local HVAC businesses quote it.