Understanding Mold

Molds are part of the natural environment. Molds are fungi that can be found anywhere – inside or outside – throughout the year. About 1,000 species of mold can be found in the United States, with more than 100,000 known species worldwide.

When excessive moisture or water accumulates indoors, mold growth often will occur, particularly if the moisture problem remains uncorrected. While it is impossible to eliminate all molds and mold spores, controlling moisture can control indoor mold growth.  Molds are usually not a problem unless mold spores land on a damp spot and begin growing. They digest whatever they land on in order to survive. There are molds that grow on wood, paper, carpet, foods and insulation, while other molds feed on the everyday dust and dirt.

Since mold requires water to grow, it is important to investigate the source of the moisture to prevent mold growth.

Hazards of Mold in Your Ductwork

Ventilation systems are designed to distribute a recirculate air within a home.  If mold growth is within the ventilation system, or near an air intake, mold spores can be spread throughout a home.

“Toxic mold syndrome” remains controversial and unproven, but experts agree that it’s best to limit exposure to molds.  The most likely adverse reaction to mold is a respiratory allergic reaction in mold-sensitive people. These reactions are similar to other respiratory allergies, causing sneezing, watery eyes, nasal discharge and congestion.

Cleaning Air Ducts

Consider having the air ducts in your home cleaned if there visible mold growth inside hard surface (e.g., sheet metal) ducts or on other components of your heating and cooling system.

There are several important points to understand concerning mold detection in heating and cooling systems:

• Many sections of your heating and cooling system may not be accessible for a visible inspection, so ask the service provider to show you any mold they say exists.
• You should be aware that although a substance may look like mold, a positive determination of whether it is mold or not can be made only by an expert and may require laboratory analysis for final confirmation.
• If you have insulated air ducts and the insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.
• If the conditions causing the mold growth in the first place are not corrected, mold growth will recur.

Chemical Off Gassing

Organic chemicals are widely used as ingredients in cleaning and sanitizing products.  Volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids.   Even a nearly odorless material can cause significant problems when re-circulated through air ducts in a closed environment.  VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects.

NADCA’s Position Regarding the Use of Antimicrobials

The National Air Duct Cleaners Association’s new position regarding the use of antimicrobial chemicals is as follows: “At this point in time, until EPA clarifies their position, NADCA does not recommend the use of any sanitizer or disinfectant products in air ducts.” This position was adopted to generate awareness among NADCA members of the potential legal liabilities they face by selling and applying antimicrobial chemicals. This is strictly a matter of managing legal risks. NADCA’s position deals specifically with sanitizers and disinfectants, not with any other product claims. Also, this position covers only air ducts, not HVAC components such as coils

No EPA Registered Products for Fiberglass Air Ducts

There are no products that are currently registered by EPA as biocides for use on fiberglass duct board or fiberglass lined ducts so it is important to determine if sections of your system contain these materials before permitting the application of any biocide.

If  You Choose to Use Chemicals in your Air Duct Cleaning Project

• Review the product sheet showing usage and application of the product.
• Review the Material Safety Data Sheet (MSDS) to understand if chemicals will cause any health or property concerns.
• Review the Fact sheet on the product classification being applied.

If You Have a Problem Related to Chemicals Applied Within Your Air Ducts

• Open doors and windows to ventilate the area with fresh air.
• Operate the fan of the HVAC system
• Exit the premises if negatively affected.
• Contact and Industrial Hygienist to discuss the problem.  Be sure to have a copy of the MSDS.

What makes Humid Climates Uncomfortable?

Humid climates have a high amount of water vapor in the air.  When it’s hot, high humidity makes people feel hotter because it reduces the ability to evaporate moisture from the skin.  In humid climates, becoming comfortable means going into a conditioned space.

Potential for Mold Growth

While mold spores are in every region and every climate, mold growth is highly dependent on the amount of humidity.  Mold growth typically occurs when an environment reaches a relative humidity of 60 percent or greater in a 72 hour span.  If mold is found within your home or workplace remediate the problem immediately, mold spores can be distributed throughout the home or building through the HVAC system impacting indoor air quality.

Air Conditioning in Humid Climates

Air conditioning coils serve a very important role in regulating temperature and humidity in humid climates.  As air passes through the evaporative coil of the air conditioner, heat and moisture are removed from the air.  To a degree, the lower the humidity level, the more comfortable you will feel at a given temperature.

Air Duct Cleaning and HVAC Maintenance

Overtime foreign debris is drawn into the evaporative coils and fan blower of the air conditioning system, gradually decreasing air flow and energy efficiency.  Maintaining HVAC system, will keep your cooling and heating components operation at peak energy efficiency, and prevent potential indoor air quality problems.  Yearly air conditioner inspections and routine air duct cleaning with assure maximum efficiency.

Whether your heating or cooling system uses natural gas, fuel oil or electricity it is a good idea to make it as efficient as possible.  Using less energy saves money and is better for the environment.

• Install a programmable thermostat: these thermostats automatically turn down your system during periods when your typically away from home.
• Change your air filter: Make sure to change your air filter regularly.  A clogged  filter will restrict air flow and cause your system to work harder and use more energy.  Most experts reccomend changing your air filter every two months.
• Seal your air ducts: Sealing your ducts will also save you money in the long run.  You could be loosing nearly all your heating and cooling before it reaches your vents.
• Clean your heating and cooling system: This is more than just duct cleaning, it involves cleaning all the components that the airstream touches in your heating and air conditioning system.  NADCA recommends cleaning the furnace, cooling coils, blower motor, and the ductwork.  Every part of the system is checked and cleaned, not just the ducts.

So how does cleaning your heating and cooling system save you money?

A dirty cooling coil reduces efficiency:  to cool your home air is blown across cold metal coils.  When the coils get clogged with dirt, airflow is restricted and air can no longer contact the metal.  This blocks airflow and limits the coils ability to properly cool the air.  Even in the winter months these dirty coils contine to reduce air flow through your furnace.  This means that the system losing efficiency all year long.

Duct Cleaning

Proper cleaning of an entire heating and cooling system takes technical skill and attention to detail, that is why it is important to rely on a company that is specifically trained and experienced in this type of cleaning.  NADCA members specialize in optimizing the efficiency and life of your system.

Remeber clean systems use less energy and clean systems last longer saving you money now and in the years to come.

The US Environmental Protection Agency states that poor indoor air quality is one of the top five environmental threats to our country. So why does the EPA feel so strongly about indoor air in homes and workplaces? Well, according to the EPA, indoor air is on average a staggering three to five times more contaminated than outdoor air and in some instances as high as seventy times.

So why is indoor air so much worse in our home than outdoor air?

The answer is in modern day construction practices. Homes are being built more air tight in an effort to be more energy efficient and environmentally conscious. Older homes are being re-insulated and getting air tight window upgrades. The result is less drafty homes that no longer have natural ventilation to bring in fresh air.

Normal everyday living provides an ongoing source of airborne contaminants like dust, dander, chemicals and other allergens. These pollutants become trapped in your home due to this poor ventilation and then are re-circulated by your heating and cooling system.

So what does this mean for you?

The average American family now spends ninety percent of their time indoors. That means that the bulk of our days is spent breathing in these irritants and pollutants and the health effects are significant. Dust, pollen, household chemicals and smoke can create an unhealthy situation in your home for everyone, but especially for people with compromised respiratory systems such as children, the elderly, and people with asthma and allergy sufferers.

So what can you as a homeowner do to improve your air quality?

Today doctors agree that one of the healthiest things to do is to minimize your exposure to these indoor pollutants, allergens and irritants in your home. One of the most logical places to address indoor pollutants is in your heating and cooling system. Think of this system as the lungs of your home. It takes in air and breathes it out; it circulates all the air and everything in the air throughout your home. In fact, on average all the air in your home passes through your heating and cooling system five to seven times each day.

Begin by making sure that you regularly change furnace filter. While these filters do not eliminate airborne contaminants they can help reduce pollutants from entering your furnace and circulating through the house. Most experts recommend replacing your filter every two months.

Another important step to take to improve the quality of the air in your home, and one that many overlook is having your heating and cooling system thoroughly cleaned. As polluted air is re-circulated through your heating and cooling system dust, dirt, and contaminants are deposited throughout the system overtime. These subtle particles are then picked up by the airstream and are then pushed back out into the living areas of the house to be breathed in by family members. In a large number of homes the heating and cooling system has never been cleaned. Even in newer homes or homes undergoing renovation contaminants such as sawdust and drywall dust left over from construction process are deposited in your ducts.

So how clean is the heating and cooling system in your home? Here is a quick way to check. Remove a vent cover and use a mirror and flashlight to look inside. Or use a small digital camera to take a picture of the inside of your duct. If your ducts are dirty it is time to have your air ducts cleaned.

Choose a NADCA Certified Company

All NADCA members must meet a strict set of requirements:

• Comply with NADCA’s International cleaning standards
• Comply with NADCA’s code of ethics.
• Comply with NADCA’s general liability insurance requirements
• Maintain at least one certified Air System Cleaning Specialist (ASCS) on staff at all times

The Air Systems Cleaning Specialists Certification verifies that they have successfully completed rigorous testing on heating and cooling system components and cleaning techniques.

Giving your homes heating and cooling system a little attention will keep it and the air in your home cleaner and healthier for you and your family.

Compared to years ago when we heated our homes with wood or coal, a modern day heating system is a marvel of efficiency, reliability and convenience, but just like the old time systems these new systems get dirty and need to be cleaned and maintained.

How does an HVAC system Work?

Now you might be thinking “We keep a really clean home, shouldn’t out ducting heating and cooling system be clean to?”   To answer that question we have to start by looking at how you’re heating and cooling system works.  Think of your homes heating and cooling system as the lungs of your home.  The system pulls air from the rooms of your home through the return ductwork, and then the air passes through the filter before reaching the air handler or furnace where it is heated or cooled depending on the season.  Once the air is heated or cooled, it is blown through the supply ductwork and back into your home.  Some of the components of the furnace are used only during heating, others only during cooling, and others operate all the time.  Although the air is filtered, the fact is that filters cannot remove all the contaminants from the air, the system will get dirty through normal use.

HVAC components that get dirty:

• Return air ducts
• Filters
• Blower
• Heat Exchanger
• Cooling coils
• Supply ductwork

Where Does Dust Come From?

So where does dust come from?  Consider that up to forty pounds of dust is created each year from in the average six room home, this normal household dust is unavoidable as it is created by everyday living.  Every time we open the door, walk across carpeting, scratch out dry skin, or unroll paper towels we contribute to airborne dust.  Of course pets and dust emitting activities such as remodeling make the problem worse.  In fact, it’s not uncommon to find construction dust in a homes heating and cooling system years after the house was built.  On average, this contaminated air recalculates throughout your home five to seven times per day.  Why does it matter? This can develop into a serious problem.  The build up of these contaminants on components such as blowers and cooling coils can lead not only to unhealthy air for your family to breathe, but also to higher energy bills.  These contaminants can cause your system to work harder and run longer shortening the life of your equipment.  Perhaps most importantly the heating and air conditioning system needs to be cleaned to provide the thermal comfort you expect.

How Do You Inspect the Heating and Cooling System?

So how clean is the heating and cooling system in your home?  Here is a quick way to check.  Remove a vent cover and use a mirror and flashlight to look inside.  Or use a small digital camera to take a picture of the inside of your duct.  If your ducts are dirty it is time to have your air ducts cleaned.  Periodic air duct cleaning keeps your homes heating and cooling system clean and operating at peak efficiency.

Prevent a Dust Out

When central air conditioners are installed, numerous modifications are made to the furnace cabinet and supply trunk line.  Trunk lines are the main intake and distribution lines of an HVAC system.  Because of the volume of air that is circulated through trunk lines, they are often the dirtiest points of a ventilation system.  Modifications to the trunk lines disrupt and loosen debris on the walls of the trunk lines.  If the air duct are not cleaned prior to installation there is a high probability of drawing debris into your newly installed HVAC components or blowing the loosened dust and debris within your home.

Prevent Fouled Air Conditioning Coils

Home central air conditioning systems draw air from the return air vents; and blow the air through evaporative coils located above the furnace to chill the air.  To a large degree, the energy efficiency of an air conditioner is dependent on the cleanliness of the evaporative coil. When evaporative coils become fouled, they cause a number of problems:

• Decrease heat transfer: Evaporative coils are made of tiny fins designed to absorb the heat from the air, when dirt or debris enters the coil fins, it acts as an insulator preventing efficient heat transfer.

• Decrease airflow: Debris can build within the coil face preventing air to freely flow through the coil.  Fouled air conditioning coils negatively affect your HVAC system during the heating season as well.

• Clogged drain pans: As evaporative air conditioner coils absorb heat from the air, they condensate moisture which flows from the air conditioning system through a drain pan.  Moisture and debris clogs the drain of the air conditioner.

• Coil Freeze: Loosened debris within the air ducts causes air filters to load prematurely, and fouls evaporative air conditioner coils. Coils typically freeze and fail due to low air flow.

Plan and Prepare

When planning your air conditioner installation, budget air duct cleaning in your installation cost.  Coordinate the air duct cleaning to be performed before the installation of the air conditioner.  Clean air ducts will provide numerous long term benefits.

NADCA Energy Research Study

In February 2008, NADCA entered into a partnership with the Colorado University to conduct a research project that will provide members with a tool for estimating the energy savings associated with HVAC cleaning and restoration projects. The research project was also commissioned to develop a field-testing protocol for NADCA members that will facilitate collection of data to provide broader support for linking HVAC cleaning and restoration to energy savings.

Current Findings and Test Results

NADCA presented the current results of the test at the 2010 Annual Meeting.  Comparisons were made by testing air flow rates when the filter, furnace, and evaporative air conditioner coil were fouled and again when the components were clean.

It was found that a dirty filter increased the filter pressure drop, system pressure drop and reduced the air flow of the ventilation system.

Surprisingly, a clean furnace and evaporative air conditioner coil increases initial energy consumption, but lessoned the amount of time that the furnace an air conditioner had to operate to achieve the desired room temperature. Though there was initial higher energy consumption, there was a net gain in overall energy efficiency.

While further data and testing is required, the current the findings show that proper exchange rate and selection of the furnace filter, routine cleaning of the evaporative air conditioner coil, and sealing of air ducts offer the greatest benefits to energy savings.

Further Testing Underway

Currently NADCA is receiving further test results from companies engaged in the assessment, cleaning, and restoration of HVAC systems.  These test results are being sent to the University of Colorado for further interpretation.

Air sealing the building envelope is one of the most critical features of an energy efficient home.  As new homes grow increasingly tighter to achieve ever higher levels of energy efficiency, the potential for indoor air pollution also increases.

Modern Construction

During construction, there are hundreds of penetrations through a typical home’s exterior. These gaps and holes are often incurred during framing, and from penetrations for wiring, plumbing, and ducts.  Air leakage accounts for 25–40% of the energy used for heating and cooling in a typical home.  To make a home energy efficient, these gaps and holes are closed and insulated to prevent the loss of conditioned air.

Indoor Air Quality Concern

Good indoor air quality is achieved by reducing or eliminating sources of indoor air contamination and providing sufficient fresh air through the heating and ventilation system.  While older homes were not energy efficient, they typically did not have problems with indoor air quality because they allowed for fresh air to freely circulate within the home.

As new homes grow increasingly tighter to achieve ever higher levels of energy efficiency, potential indoor air pollution also increases since many conventional building materials emit volatile organic compounds like formaldehyde.  While energy efficiency is important, gains in energy efficiency, especially in new homes, should not come at the expense of deterioration of indoor air quality and corresponding adverse health impacts.

Source Elimination and Control

The best way to address indoor air pollution is through aggressive source elimination and control.  Pollution should be prevented or reduced at the source whenever feasible.

• Building materials:  If you are having the home constructed or remodeling your home select materials that do not emit volatile organic compounds.
• HVAC System: Make sure your HVAC system distributes the minimum level of outdoor air throughout the home using whole-house mechanical ventilation.
• Sealing Air Ducts:  Sealing ducts can help improve indoor air quality by reducing the risk of pollutants entering ducts and circulating through your home as well as preventing the loss of conditioned air.
• Air Duct Cleaning: Ventilation systems distribute the air you breathe. Have the air ducts and HVAC system professionally cleaned to remove construction debris and pollutants.
• Monitor use of household cleaning supplies:  Some household chemicals can be extremely dangerous.  Choose environmentally safe cleaning supplies, and make sure that the area is well ventilated.
• Check exhaust systems:  Make sure exhaust fans are clean and unobstructed. Exhaust systems are responsible for removing moisture, odors, fumes, and carbon monoxide.

Setting the Standard for Indoor Air Quality

ASHRAE, the American Society of Heating, Refrigeration and Air Conditioning Engineers developed Standard 62.2, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings.  The standard, which is widely accepted by green builders, state and local around the counties, defines the roles of and minimum requirements for mechanical and natural ventilation systems and the building envelope in order to provide acceptable IAQ in low-rise residential buildings.

10 Steps to Ensure Good Indoor Air Quality

1. Vent bathrooms, kitchens, toilets and laundry rooms directly outdoors.  Use energy efficient and quiet fans.
2. Avoid locating furnaces, air conditioners and ductwork in garages or other spaces where they can inadvertently draw contaminants into the house.
3. Properly vent fireplaces, wood stoves, and other hearth products; use tight doors and outdoor air intakes when possible.
4. Vent cloths dryers and central vacuum cleaners directly outdoors.
5. Store toxic or volatile compounds such as paints, solvents, cleaners, and pesticides out of the occupiable space.
6. Minimize or avoid unvented combustion sources such as candles, cigarettes, indoor barbecues, decorative combustion appliances or vent free heaters.
7. Provide operable windows to accommodate unusual sources or high-polluting events, such as the use of home cleaning products, hobby activities, etc.
8. Use sealed-combustion, power-vented or condensing water heaters and furnaces.  When natural-draft applications must be used, they should be tested for proper venting and should be located outside the occupied space when possible.
9. Put a good particle filter or air cleaner in your air handling system to keep dirt out of the air and off your ductwork and heating and cooling components.
10. Distribute a minimum level of outdoor air throughout the home using whole-house mechanical ventilation.

Source: ASHRAE Standard 62.2 Ventilation and Acceptable Indoor Air Quality on Low-Rise Residential Buildings, and 2001 ASHRAE Handbook, Fundamentals, Chapter 26, Ventilation and Infiltration.