Mold and Your Air Conditioning and Heating System

  • Blown Up Picture of MoldHow do I know if I have a mold problem?
  • Could my air conditioning and heating system be part of the problem?
  • Who can test for mold and other Indoor Air Quality problems?

The Facts About Mold and Your Home
Mold spores are literally as old as dirt. Check out Leviticus Chapter 14 (written over 3000 years ago) for mold remediation instructions. In recent years more people have become sensitive to mold. To some mold can be toxic. Yet some people aren’t sensitive to mold at all. Today’s homes are better insulated and tighter. There’s more potential to trap the moisture that can promote biological growth.

Mold Ceiling in HomeAt what point can mold become a threat?
Mold has been called ‘Mother Nature’s reclaiming process.” Mold spores are literally everywhere. A typical healthy house is host to tens of thousands of mold spores. The problem begins when mold spores find an environment where they can reproduce exponentially. Mold needs moisture to grow. Control the moisture and you can control mold growth. If good housekeeping keeps it in check, the problem is often easily cleaned up.

What if there appears to be mold in my air conditioning system?
It’s your air conditioning system’s job to ventilate your home. The ducts are designed to supply and return airflow to each room. If there is a mold infestation on your home, an increased amount of mold spores become present. As the air conditioning system constantly recycles air throughout your home, it becomes infected by the active mold culture and often is first noticed on the registers. In rare cases mold can be caused by the air conditioning system due to lack of maintenance, clogged or leaking drain pans, etc. These HVAC-related causes can usually be corrected by a qualified heating and air conditioning contractor.

Mold on WallsCan my air conditioning system cause mold?
A properly designed, installed, and maintained air conditioning system should not cause mold. However, while an oversized or improperly designed system may somewhat cool your home, it may not remove enough moisture. Too much moisture in your home’s air can increase the potential for mold growth. Improper installation, lack of maintenance, and water drainage issues can also lead to biological growth.

Frequently Asked Questions

QUESTION: Can mold cause health problems?
ANSWER: Many people are unaffected by mold growth. Other people can become ill when exposed to high levels of mold. Consult your physician if you suspect an intolerance to mold.

QUESTION: How can I tell if mold in my house is the bad kind?
ANSWER: It takes a laboratory and a 600X microscope to identify a mold species. Your doctor can run a series of tests to determine your reactions to various molds. Mold identification is usually outside the expertise of your air conditioning contractor and should be performed by a qualified specialist.

QUESTION: What causes mold spores to grow?
ANSWER: Mold spores are everywhere. They feed on just about anything organic that can rot. But they exist in a dormant state until one missing ingredient is added: Moisture. At 70% relative humidity, it takes 100 days to establish a culture. At 90% humidity mold can establish a culture in 3 days. Moisture is at the root of all mold problems.

QUESTION: What can I do to control mold?
ANSWER: Typical household cleaning contains mold growth in visible areas and normal household cleaning products can clean susceptible surfaces including the shower and tub areas, or around sinks. Use exhaust fans after showering. Repair any plumbing or roof leaks. Always clean up spills or flooding immediately and control moisture in basements.

QUESTION: What should I expect from my heating/cooling contractor?
ANSWER: A well trained air conditioning and heating contractor is your Indoor Air Quality specialist when addressing heating, cooling, basic filtration and ventilating your home. But when it comes to air particle testing, taking mold samples, biological identification, mold remediation, or health issues, you should look to a specialist for help. These tests are outside the licensing and training of a typical air conditioning contractor.

QUESTION: Who should I contact if I have a serious mold issue?
ANSWER: There are a number of organizations you can contact to be put in touch with a mold testing or remediation specialist. You can start by contacting one of the following organizations or visiting their web sites:

International Association of Mold Remediation Specialists
P.O. Box 273, 4750 Bryant Irvin Road
Fort Worth, TX 76132

Indoor Air Quality Association
12339 Carroll Avenue
Rockville, MD 20852
Phone: 301-231-8388

American Industrial Hygiene Association
2700 Prosperity Ave., Suite 250
Fairfax, VA 22031