Testing & Process · 7 min read
A DNA snapshot of the dust in your home.
ERMI & HERTSMI-2 Dust Testing
Quantitative DNA-based dust testing that scores the mold history of a home, interpreted by licensed assessors alongside a physical inspection.
ERMI and HERTSMI-2 are DNA-based dust tests. Instead of counting spores floating in the air during a single hour, they analyze settled dust that has been accumulating for weeks or months and identify the mold species present by their genetic signatures. The result is a score that many physicians and mold-sensitive clients in Central Florida ask for by name.
UES offers ERMI and HERTSMI-2 sampling through our accredited laboratory partners as part of a licensed mold assessment. We collect the dust, document the home and interpret the score in context, because a number on its own tells you very little about where the moisture problem is or what to do about it.
When ermi / hertsmi-2 is the right call
- Your physician or health practitioner has asked for an ERMI or HERTSMI-2 score before treating a suspected mold-related illness.
- You are mold sensitive or recovering from a mold exposure and want to know whether a home is safe to move into or return to.
- A previous inspection found nothing visible, but symptoms persist in one home and ease when you travel.
- You are comparing two or more rental or purchase options and want a consistent, repeatable measure across each property.
- You want a documented baseline before a renovation, a remediation or a long snowbird absence.
How it works
- 1
A Florida DBPR licensed assessor walks the home first, noting moisture history, HVAC condition and any areas of visible concern.
- 2
Settled dust is collected from agreed locations, typically above floor level on surfaces that have not been cleaned recently, using the collection method specified by the laboratory.
- 3
Samples are sealed, labeled and shipped under chain of custody to an accredited laboratory for DNA analysis.
- 4
The lab reports the concentration of each target species and calculates the ERMI or HERTSMI-2 score.
- 5
We review the score against the inspection findings and explain what it does and does not mean for your home in the UES Client Portal.
What ERMI and HERTSMI-2 actually measure
ERMI stands for Environmental Relative Moldiness Index. It was developed by the United States Environmental Protection Agency as a research tool to compare the mold burden of homes across the country. The method uses quantitative PCR, a DNA technique, to measure the amount of each of thirty-six mold species in a dust sample. Twenty-six of those species are associated with water damage and ten are common everywhere. The score is the difference between the two groups, so a higher number suggests a home with more water-damage-related mold than typical.
HERTSMI-2 is a shorter index built from five of the ERMI species that are most often linked to health complaints in water-damaged buildings. Because it is smaller and less expensive to run, it is frequently used to decide whether a home is reasonable for a sensitized person to occupy, and to re-check a home after remediation. Both tests look backward in time. Dust is a record of what has settled over months, which is exactly why these tests can detect problems that a one-hour air sample may miss.
Why the score needs an inspection behind it
The EPA developed ERMI for population research, not as a stand-alone pass or fail test for an individual home. The agency has been clear that the index was never validated for that purpose. That does not make the test useless. It makes interpretation the important part. A high score in a Florida home can come from an active leak behind a wall, from a past event that was never properly cleaned, or from dust tracked in from a garage or lanai. Only a physical inspection with moisture meters and thermal imaging can tell you which.
This is where an independent assessor matters. UES does not remediate and does not accept referral fees from contractors, so we have no reason to turn an ambiguous score into a scope of work. When we pair the dust result with a forensic visual inspection, you learn whether the number points to a current moisture problem that needs correction or to legacy dust that needs a thorough cleaning and a follow-up test.
Florida factors that shift dust results
Central Florida homes present a few conditions that can push an ERMI or HERTSMI-2 score around. Air conditioning runs most of the year, so settled dust is drawn into returns and redistributed through the duct system. Slab-on-grade construction and block walls hold moisture that can feed growth at the base of walls behind furniture. Homes that sit empty for the summer while owners are up north often run the thermostat warm, and humidity climbs. Vacation rentals near the attractions see heavy turnover and inconsistent cleaning.
- Tell us when the home was last deep cleaned so we can judge how much history the dust represents.
- Avoid dusting or vacuuming sample areas for several days before the visit.
- Let us know about past leaks, roof repairs or plumbing failures, even if they were fixed.
- Keep the air conditioning on its normal schedule so the sample reflects real conditions.
When a dust test is not the right tool
If you can see mold, smell a strong musty odor in one room or have an active leak, a dust index will confirm what you already suspect without telling you how far it has spread or where it starts. In those situations we usually recommend a Comprehensive Mold Assessment with targeted air and surface sampling first. Dust testing is most useful when the question is about the overall history of a home, when a medical provider has asked for a specific score, or when you need to compare properties against a common yardstick. A dust test also cannot locate moisture, so it should never be used to write a remediation protocol on its own. We will tell you honestly which approach answers your question, and many clients choose to combine the two.
ERMI / HERTSMI-2 questions
Is ERMI testing accurate?
The laboratory DNA analysis is precise and repeatable. The uncertainty lies in what the score means for one home, because the EPA designed the index to compare large groups of homes rather than to grade an individual property. When the result is read alongside a licensed inspection, moisture readings and your own history of the house, it becomes a useful piece of evidence rather than a verdict.
What is the difference between ERMI and HERTSMI-2?
ERMI measures thirty-six species and produces a broad index of a home's mold burden. HERTSMI-2 measures five species most often associated with health complaints in water-damaged buildings and is typically used for occupancy decisions and post-remediation re-checks. Many clients begin with HERTSMI-2 and move to ERMI if the picture is unclear.
Can I collect the dust sample myself?
Kits exist, but a self-collected sample lacks chain of custody, a documented collection method and any inspection of the home. If the result will be shared with a physician, a landlord, a seller or an insurer, a sample collected and documented by a Florida DBPR licensed assessor carries far more weight.
How long do ERMI results take?
Laboratory turnaround for DNA analysis is generally longer than for standard spore trap air samples, and it varies with the lab's workload. We give you the expected timeline when we schedule the visit and post the results, with our interpretation, in the UES Client Portal as soon as they arrive.
How do I book an ERMI or HERTSMI-2 test in Orlando?
Book online at /book-assessment or call (407) 438-4684 and tell us a dust test has been requested. We serve Orlando, Leesburg, The Villages and all of Central Florida, and we will recommend whether to pair the dust test with air sampling based on your situation.
Need ermi / hertsmi-2?
Independent, lab-verified answers from Florida licensed assessors who never sell remediation.
What our clients say
“The owner and her team are incredibly thorough. They spent hours in my home and shared what they were doing along the way. UES goes way beyond what I expected, providing an education along with a comprehensive analysis. A multipage report along with recommendations was professionally presented and staff was available to answer all of my questions. I have complete faith in UES's procedures and findings and highly recommend them with no reservations.”
“No home owner wants to hear the word "mold", but if you do, you need the best to support you through the journey. Ultimate Environmental Solutions (UES) is the best. Initially, I didn't know where to turn and UES was highly recommended to me by a friend. The owner and her team walked me through every step and created a plan of action. They were kind, responsive, professional, but most of all knowledgeable. The thorough protocol report they provided was a valuable asset in claiming mold and water damage compensation from my insurance company. Do not cut corners when it comes to mold. The owner is an expert in her field. She is my trusted ally and truly went above and beyond.”
“If you are wondering who to trust with the health and safety of your family, look no further than UES Ultimate Environmental Solutions, Inc. The owner came out to our home and put my mind and wallet to ease. She was transparent, authentic, and professional. She truly cared about my family and our needs, including financial and wellbeing. It's hard to trust anyone anymore. I promise you; you can trust UES. Once you meet her, you'll immediately know why I felt compelled to leave this review as soon as she left my home. Thank you for UES.”
“Ultimate Environmental Solutions provided the environmental testing during a remediation project due to hurricane damage to one of my commercial office building. I found UES to be very professional and easy to work with. I will definitely reach out to them should the need arise.”
“My experience with UES was wonderful. The inspector was friendly, professional and thorough. The office staff was very competent and helpful. The mold specialists spent a great deal of time with me on the phone assessing my needs and guiding me to the type of inspection that was right for me, and she was very careful and thorough in explaining to me the results of the lab results. I HIGHLY RECOMMEND this company to anyone searching for mold inspections.”
“Unbelievable customer service and professional knowledge even to non-customer!!! Right off the bat, the owner knew her FL company couldn't help my out-of-state situation; yet she spent her time offering me direction, tips, pointers, pointing me to national testing lab and national organizations which may be able to provide environmental test kit and consultants in my state to help me with the vapor invasion situation at my town home. She even helped me understand a bit on everything from typical airflow of building, firewall building code, construction layout of high density residence... The information she gave me will save me hours of researching. A true rarity.”
“Prompt, thorough and efficient. Did an in-depth survey and report of findings, after our recent fire. Not someone I want to see, again, LOL. But, would highly recommend their services.”
“The UES team were honest, thorough and experts in their forensic analysis of my home environmental inspection. I highly recommend them for anyone concerned with potential mold issues in their home.”
“The owner and her team were very thorough and very knowledgeable. We've been dealing with them for a couple years now. Look no further for mold experts.”
“I highly recommend this company. I used their services on two separate occasions. The owner is awesome. The report was very comprehensive but she still took the time to review it with me by phone to ensure I had all the necessary information. The team are experts in what they do. I found them to be very knowledgeable, punctual and pleasant to work with.”
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Clear, honest answers about the air you breathe and the building you live or work in.
Independent, state-licensed mold assessors and indoor air quality consultants since 2000. We test, we diagnose and we document; we never sell remediation, so the only thing our report has to serve is you.
Ultimate Environmental Solutions, Inc.
Florida licensed mold assessors · Leesburg & Orlando · Serving the entire state