Indoor Air Quality and Your Homes Heating and Cooling System

What Does the EPA say about Indoor Air Quality?

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.

NADCA Energy Research Study

For decades the National Air Duct Cleaners Association (NADCA), has been educating consumers on the process and benefits of air duct cleaning. Currently there is research study underway to measure the correlation between energy pressure drop and energy savings.

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.

Top 10 Ways Homeowners Can Ensure Good Indoor Air Quality

Ensuring good indoor air quality is easy once you have an understanding of the components that effect your homes environment.  Using the steps below, perform a quick checklist to improve your indoor quality.

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.