Category
HVAC
Air conditioning systems, ducts and drain pans — where mold spreads fastest and how it is handled.
Topics
- Mold in air conditioning systems and ducts An AC system is a moisture machine: the cooling coil pulls water out of the air into a drain pan. When the pan or drain line clogs, or ducts sweat in a hot attic,... Best practice
- Mold in the HVAC system: how the S520 says to handle it HVAC systems can be a source of mold, a pathway that spreads it through the house, and a place it builds up and hurts the system's performance. So the S520 says the... Best practice
- HVAC systems after water damage An HVAC system that gets wet can quit, run poorly, or push humid air through the whole house. If Category 2 or 3 water reaches it, it can carry that contamination... Best practice
- HVAC systems under Texas mold rules Texas applies the same assessment rules (§78.100) and remediation rules (§78.120) to mold in heating, ventilation and air conditioning systems as to any other part of... Texas law
- How HVAC systems spread or prevent mold Heating and cooling systems control the conditions that cause condensation, and they also move air through the whole house. R520 says this makes them both a cause and... Best practice
- Cleaning coils, blowers and ducts; chemicals in HVAC systems Once the system has been assessed and any mechanical fixes made, cleaning follows the NADCA ACR standard. If the Condition of the system is unclear, an IEP with HVAC... Best practice
Questions & answers
Should I test my air ducts for mold?
Duct testing can be worthwhile if you have musty odors, visible mold at supply vents, or unexplained indoor air quality problems. A visual inspection with a camera is the first step. Air sampling from supply registers can detect elevated spore levels. Surface sampling from inside ducts can confirm the species present. The challenge with ducts is that even a positive test doesn't always mean the whole system needs replacement — sometimes targeted cleaning and source correction is enough. A mold assessment that includes HVAC evaluation gives you the full picture of what's actually driving any air quality problems.
Based on: EPA; IICRC S520