Mold Testing/Inspection Questions

Hi, I bought a Breeze ET, and took the InterNachi Mold Course. I called around to see what other companies are charging and what they offer. Called 5 companies, got different procedures from each one. Some don’t do an exterior test, some do only 1, while IAQ2 requires 2.

  1. If I was going to do a air sample in a condo on the 12th floor, should I still do an outdoor test on the balcony even if it has a balcony above it or on 2 sides of the building on the ground floor? Or should I just compare the inside to some average result?

  2. If the temperature on the exterior is very calm, would you still do 2 exterior test even if it’s not windy?

  3. If it was for a real estate transaction and they just wanted to test the air quality, as part of their home inspection, would you recommend an indoor test for every 1000 sf? Or one on each floor? Most seem to offer 1 outside, 2 inside.

  4. What meter would you recommend to record RH, Temperature, carbon monoxide, carbon dioxide, etc. Some offer formaldehyde as well. Any good meter recommendation?



Hey David how ya doing?

When you’re on the 12th floor the spore count is not a valid baseline control.
Not many spores up there. You may get a false positive elevation inside. I just did an assessment yesterday on the 4th floor. Took my sample downstairs at the entry. Try to stay away to adjacent bushes, etc.

I only take 1 sample outside.

My spore traps are good for 400-600 SF. They do not “go around corners”.
Instead of one in each room I usually will put one in the let’s say - family room, master suite, other area that the family will spend time in.
Sometimes the client has a compromised child & they want one in a bedroom.


Thank you Mark for the details, I really appreciate it.

  1. Why do you take 1 sample outside and not 2? Do you find that they often have the same result?

  2. If there isn’t much mold spores many floors up a building, even if the unit has no mold at all, the exterior sample shouldn’t it be completely different than the one on the inside? For example, a unit went through a water damage remediation and they want to test the air for mold, do you think it still make sense to do an exterior sample?

Thank you,


I’ve always taken 1 outside. Just require 1 for a baseline comparative.
Other factors prevail where you take the outside.
Stay away from vegetation. Many homes down here have a screened pool enclosure. I won’t go there 'cause the chlorinated water vapor may dilute the spore count.
At $150-175/test things get pricey for the client. That’s why they usually agree for 2-4 total.

The unit will always have mold - it’s the largest biomass on earth.
The object is a comparative between the separate indoor samples & outside.
We’re looking for the spore counts to come back the same or less than outside.
I don’t wanna see it 5-10 times higher inside. The air is elevated.

When I perform “clearance testing”, 3 samples required.
Let’s say
1 inside the containment area after finished cleaning but still in place
1 outside the containment to check for unintended cross contamination
1 outside baseline control

I privately sent you a full assessment for review.


Great info again and thanks for the PM.