Using Carbon Dioxide (CO2) As An Indicator Of Indoor Air Quality (IAQ) Issues

Evaluating The Carbon Dioxide (CO2) Levels Inside a Home as a Clue That May Indicate Mold

July 24, 2023

Introduction

Regal Home Inspections, LLC has always been as diligent as possible with regard to meeting and often exceeding the letter and spirit of the NJ Home Inspection Standards of Practice (The Law). We’ve received many compliments on the comprehensive nature of our inspections and quality of our reports.  The Law states what must be done, what is excluded and leaves open to individual inspection companies to expand into ancillary services. As an example, both of the home inspection team at Regal Home Inspections is, of course, licensed in NJ to conduct the home inspection. They are also both certified by the NJ DEP as Radon Measurement Technicians. Frank is also licensed by the NJ DEP as a Pesticide Applicator which allows him to conduct termite inspections and prepare the industry recognized Termite Report (NPMA-33).  Brian is also licensed by various State entities to perform lead paint evaluations (Lead Safe inspections) and collect dust samples to check for lead paint dust.

As of this writing, New Jersey does not have any license requirements for mold testing, sewer scopes, oil tank sweeps, etc. and we opt to allow others address those.

A conversation about, “Looking for mold” often takes place with prospective clients and we’re very consistent to say, “We don’t look for mold”.  Mold can be in dozens of places inside a home; Under carpets, inside walls, behind bathroom vanities, etc.  We feel that if you tell someone that, “Yes, we look for mold” then if you look in 100 places and don’t see any it’s possible that after the client moves in and changes the carpets and there’s mold under the padding for a carpet they may complain because you said, “Yes, we look for mold” (Which of course we do not).

Taking air samples for mold is one way of determining if high levels of mold exist inside a home but it’s costly. A special vacuum pump is used to collect air samples. Multiple air samples are taken then sent to a lab for evaluation. The lab’s evaluation includes identifying the types of mold spores collected and the amount. Some mold is expected. Elevated levels are not. Again, each air sample costs the consumer about $125.00 and usually, at least 3 are needed (One of which is a control sample taken outside the home being tested). There may be as many as 6 or more in many instances and the cost can easily approach $1000 just to, see if there’s mold.

Solution

CO2 meter in calibration mode.
CO2 detector mounted on a tripod. Indoor measurement is 796ppm. Like many homes, the windows and doors have been kept closed for weeks while the AC has been running. Same room after the windows were opened measured CO2 @ 554ppm.“See” if there’s mold.

We have recently learned about another, less expensive way to predict if a home has mold.  In researching the new methodology we learned that it has been in use with the US Department of Agriculture for years (Since about 2009).

For the home buyer, it’s predictive.  If this new methodology provides normal results then the research indicates that there aren’t elevated levels of mold growth inside a home.  However, if the methodology has different results, that indicates that high levels of mold exist THEN, further evaluation is required by a mold specialist.

The predictive methodology is measuring the Carbon Dioxide (CO2) in the air inside a house, room, basement, etc.  Research that we’ve reviewed state that normal outside CO2 levels are about 400 parts per million (ppm). If the levels of CO2 spike, 3000 or more ppm, this is a red flag that there may be high levels of mold in the house. You see, according to a USDA researcher, ”monitoring CO2 levels might provide more accurate results to detect if mold is growing.  Monitoring mold by measuring CO2 : USDA ARS

The researcher says that,As mold grows it gives off carbon dioxide. Therefore, if there is a CO2 spike, there is likely an increase of mold activity.”

From Facts About Indoor Mold – RadGreen

“Seeing a spike in CO2 levels could show severe mold growth. Standard carbon dioxide runs about 400 parts per million (ppm), and if the sensor reads more than 10,000 ppm, that could mean severe mold activity, and then 2,000 to 3,000 ppm could mean some mold activity.”

“Indoor mold is the mold that causes problems. Mold growth can cause damage to buildings and furnishings. To reduce mold growth in an indoor space, controlling the humidity levels is very important. Keeping humidity levels between 30-60% can reduce the amount of moisture in the air to keep mold growth low.(2) Ventilating the space is another way to reduce mold growth in indoor spaces. Inspecting your indoor space is vital to ensure that the indoor environment stays healthy. Responding quickly to leaks and spills and cleaning them is essential to prevent growth in those areas.”

Regal Home Inspections, LLC, is undergoing the implementation of the use of carbon dioxide (CO2) detectors during the course of our home inspections. Training for Indoor Air Quality was just completed. Just like the termite inspection, radon test or lead paint, it will be another ancillary service allowed by the home inspection Law.  During the course of a home inspection a CO2 detector will be used in different areas of the house. For example, we’ll check the CO2 levels in the basement, kitchen area and bedroom area. If the CO2 is in the 600ppm range then, as the reference material indicates, that’s a level that is expected inside. If it’s elevated from that and spikes to 2000ppm – 10,000ppm then the client will be advised to get a mold specialist for further testing. This service will be offered in conjunction with our standard home inspections at a reasonable price. It will also be offered as a standalone service.

“Seeing a spike in CO2 levels could show severe mold growth. Standard carbon dioxide runs about 400 parts per million (ppm) [outside], and if the sensor reads more than 10,000 ppm, that could mean severe mold activity, and then 2,000 to 3,000 ppm could mean some mold activity.”

“Indoor mold is the mold that causes problems. Mold growth can cause damage to buildings and furnishings. To reduce mold growth in an indoor space, controlling the humidity levels is very important. Keeping humidity levels between 30-60% (20% – 50% is a tighter range which is beneficial) can reduce the amount of moisture in the air to keep mold growth low.  Ventilating the space is another way to reduce mold growth in indoor spaces. Inspecting your indoor space is vital to ensure that the indoor environment stays healthy. Responding quickly to leaks and spills and cleaning them is essential to prevent growth in those areas.”

Regal Home Inspections, LLC, is undergoing the implementation of the use of carbon dioxide (CO2) detectors during the course of our home inspections. Just like the termite inspection, radon test or lead paint, it will be another ancillary service allowed by the home inspection Law.  During the course of a home inspection the CO2 detector will be used in different areas of the house. For example, we’ll check the CO2 levels in the basement, kitchen area and bedroom area. If the CO2 is in the 500ppm to 600ppm range then, as the reference material indicates, that’s a level that is expected. If it’s elevated from that and spikes then the client will be advised to get a mold specialist for further testing. This service will be offered in conjunction with our standard home inspections at a reasonable price. It will also be offered as a standalone service.

 

Pricing:                                                       With a Home Inspection         Stand-alone

Radon                                                          $50 – $100                             Minimum $175

Termite                                                         $50 – $100                            Minimum $195

Lead Paint                                                     Varies*                                 Varies*

Carbon Dioxide (CO2)  Measurement         $150                                       $350+

 

*- Different municipalities have different requirements. Some allow a visual, “Lead Safe” inspection and others require swabs be taken in every area where children are likely to spend time; Bedrooms, playrooms, Living rooms, etc.