Indoor Air Quality IAQ

Poor air quality can lead to poor health

No home is immune to indoor air quality problems. Results from a government study of in-home air tests across North America found 96% of homes had at least one IAQ problem

• 86% had high levels of dust, pollen, and viruses
• 71% were filled with odors
• 46% had problems with temperature and humidity

What causes indoor air problems?

Pollutants can come from many different sources inside the home. For instance carpeting, upholstery, cleaning chemicals, and plastics release chemicals into the air call Volatile Organic Compounds. High temperature and humidity increase concentrations of mold and bacteria. Leakage or negative pressurized homes pull dust, dirt, and pollens into the home. Cooking orders, pet dander, dust mites, viruses, and fungi are constantly present in all homes as a normal part of life.

Many studies have shown that as homes become tighter and more energy efficient, more contaminants can become trapped inside. Our homes air can be full of pollutants, including:

The typical throwaway 1” furnace filter only traps about 5 - 15% of these polluting particles

Media air filters – Use a disposable filter between MERV 10 and MERV 16 to effectively filter micro particles. MERV is Minimum Efficiency Reporting Value. A higher MERV offers more effective filtration. High efficiency media air filters trap particles as small as .01 microns. That means it will remove bacteria, pollen, plant spores, some viruses, smoke, animal dander, lint and dust from the air to improve the quality of the air you breathe, far outperforming the standard throw away filters, These filters usually last 6 months to 1 year, and are very easy to service and actually cost less then buying 1" filters 3-4 times per year.

To top

Air-to-Air Exchangers- Often called HRV's (Heat Recovery Ventilators) or ERV's (Energy Recovery Ventilators), these devices bring in fresh, outdoor air without sacrificing comfort. They have a heat exchanger that transfers the energy, and in some cases, humidity from the outgoing, stale air to the incoming fresh air. They can be run on a timer, or thermostat.

The average home should have at least .35 ACH (air changes per hour). An ACH of 1.0 means that air in the home is changed once per hour. Newer, high-efficiency homes generally have an ACH rating of less than .35, and many are as low as .05. That can lead to extremely poor indoor air quality. The Lennox Heat Recovery Ventilator (HRV) provides a simple and economical way to freshen the air. Thanks to some clever engineering, the Lennox HRV is able to conserve energy from indoor conditioned air and transfer it to the outdoor air as it's brought into your home.

The Benefits

• Whole-house air purification is integrated into your forced air heating and cooling system
• Neutralizes odors of pets, cooking, smoking, chemicals, paint, solvents, carpet, etc
• Allows you to enjoy the sweet smell of fresh air during the entire year
• Helps remove micro-organisms such as spores, molds, mildews, fungi, bacteria, and viruses, and their associated odors
• Is registered as a Class II Medical Device
• Is FDA approved
• Has no costly filters or chemicals to replace

To top

Circulation of air through the ductwork falls under three headings:

• Source control, for proper humidification or dehumidification
• Ventilation, the ERV and HRV are needed to tie into tightly sealed ductwork to be effective
• Filtration, because if the air is not moving across the filter it can not clean it, and if the ductwork is leaking it will draw dust in from undesirable sources.

Air distribution is the ability to move air in the right quantity, at the proper speed, at a designed temperature, keeping in mind moisture problems, noise, and cleanliness. So you see, it is more than blowing air into a room. The size and location of ducts, grills, and registers is critical to the proper airflow required by the higher efficiency equipment. Also, the homeowner wants the system to move air quietly without a large temperature change, without drafts from air moving too fast, and without hot or cold spots from stratified air. Going beyond just comfort, proper airflow can affect personal health and the health of the home. These IAQ problems fall under the jurisdiction of the EPA and include problems like mildew and mold radon and other pollutants.

The air distribution system does not create air; it simply circulates the same air through the residence over and over again. Everyone has heard of someone getting sick because they flew on planes that re-circulate the air and germs from other passengers. The same holds true in the residence. If the air is contaminated by dirt, pollen, dust, or any other problematic sources, the result is the circulation of these products throughout the home. All of the air in your home can be completely circulated through your system in 8-16 minutes. This is the same air, dirt, and germs going around in your home.

Often overlooked in this industry is the circulation system of the air. As long as the air was coming out of the grills it seemed to be OK. If the room was too cool or too hot, another duct was added to bring in more air with little regard to the source or origin of that air.

Leaking air from the supply side of the system can cause the whole house to go into a negative pressure. When a home goes into a negative pressure, air is being sucked into every crack and crevice of the home, through electrical fixtures, sill plates, windows, and doors. This air is not conditioned air; it is often very hot or cold and with varying degrees of moisture content and dirt. This can cause higher electric bills as well as dust problems. If the air is very humid, the interior of the walls can reach dew point and mold issues can develop where it is not visible, but is potentially dangerous to the occupants.

Leaking air into the return side of the system, depending on from where it is being drawn, can have the opposite effect on the home. It will place the structure in a positive pressure. When a home goes positive it forces the clean, conditioned air out from all the same places, again costing the homeowner money. If it is a very dry climate, the moisture level drops in the residence causing low humidity issues like static electricity, dry itchy skin, nose bleeds, etc. If in a wet climate, humidity levels can be increased.

Symptoms of Circulation Problems

• Humidity high or low
• Not cooling or heating in home
• Not cooling or heating in certain rooms
• Dust in home
• Noisy supply or return ducts or grills
• Drafty rooms
• Sweating ductwork
• Moisture around grills
• Musty odors
• Air blows too cold or too hot
• Home pressure changes when blower turns on

Solutions

• Variable speed blower
• Repair duct leaks
• Replace ducts
• Add additional ducts
• Enlarge return grills
• Replace or add insulation
• Two-stage gas furnace
• Clean ductwork
• UV light

To top

Humidity is measured in Percentage of Relative Humidity (%RH) or the amount of moisture in the air compared to how much moisture the air can hold at any given temperature. The warmer the air is the more moisture it can hold before producing condensation (dew point).

If the Relative Humidity is too high we can have moisture problems. Fungus can grow, dust mites thrive, and a host of other undesirable conditions can occur.

If the Relative Humidity is too low we lessen those detrimental effects but then can have static electricity, skin disorders, nose bleeds, etc. - another group of issues we must consider.

Situation: Less Than 25% RH

• Static electricity
• Dry itchy skin
• Sore throats
• Nose irritation or bleeding
• Viruses
• Bacteria
• Respiratory infections

Situation: Over 50% RH

• Bacterial growth
• Viruses
• Fungi
• Dust mites
• Asthma
• Chemical interactions (VOCs)

Solutions

• Ensure proper pressurization of home
• Dehumidifier
• 2 stage air conditioner
• Variable speed air handler
• Proper size air conditioner (possibly too big)
• Proper airflow (CFM)
• Proper size ductwork or grills (possibly too small)
• Proper refrigerant charge in air conditioner
• Proper attic or crawlspace ventilation
• UV Lights

To top