Best Buildings for Good Air

At Healthy Air USA, we know that achieving and maintaining healthy indoor air requires you to pay attention to the components of a building and how these components impact you and the building itself.

Building Science is the study of how buildings function under various environmental conditions.

These factors play a big part in good building air and influence the performance of the entire system:

• Structure
• Ventilation and filtration

Indoor air quality can be greatly improved by using proper design strategy and good building materials. Mechanical systems should be designed and installed by trained experts aimed toward protecting the health, quality of life and productivity of the building occupants.

Moisture Movement

Moisture problems are the number one source of residential concerns. Excess moisture generated within the home needs to be removed before high humidity levels lead to physical damage to the home or mold growth. The ideal interior relative humidity levels to maintain on a seasonal basis would be 40% – 50%RH. The key to controlling relative humidity levels in a home is to maintain a moisture balance. Too much moisture can cause problems, but some moisture in the air is necessary for human health and comfort.

Relative Humidity

This is the ratio of the amount of water in the air at a given temperature to the maximum amount it could hold at that temperature; expressed as a percentage.

Pressurization

Maintaining buildings under positive pressure relative to outdoors can help to maintain indoor air quality by limiting the infiltration of outdoor air that may adversely affect thermal comfort and may contain moisture and pollutants. Allowing air to move freely and unimpaired from room to room in the conditioned areas of a home is essential. Balanced pressure helps maintain consistent temperatures without placing abnormal stress on the envelope.

Many normal household items can work against your ventilation system. Some of these include the stove vent, clothes dryer, and bathroom fan. The function of each these is to remove air from the home and push it to the outside. This can create a negative pressure in the home. If the proper amount of make up air is not supplied by the design, the negative pressure in the home will draw the air from uncontrolled areas. The uncontrolled make-up air can be from a crawlspace, cracks in the foundation, leaky window seals, the water heater flue and the chimney. When air is pulled in through the water heater flue, chimney or furnace flue, carbon monoxide is also being pulled into the home, this is called “back-drafting“. Uncontrolled air from the crawl space or foundation cracks can contain Radon, moisture, and other contaminants.

Air Leakage

Air leakage is the unintentional movement of air from one area to another. Air leaking from the ductwork (air being pushed out of the ducting system), will have a negative impact on your comfort level, heating and cooling system efficiency, and indoor air quality. To alleviate air leakage from the ducting system, all connections and transitions on the ducting system should be properly sealed and insulated.

Air leakage can also occur because of the home’s natural ‘stacking effect.’ As warmer air in the home rises, a negative pressure is created in the lower areas of the home. If mechanical ventilation is not used to create a pressurization balance, the negative pressure will be equalized by drawing unconditioned air (air leakage) through cracks, piping access holes, and porous building materials.

Temperature

Internal and external temperatures play a role in building sciences. Temperature can determine the pressurization of the home, hence affecting the comfort levels and efficiencies. In most cases, internal temperature is controlled through mechanical methods (air conditioners and furnaces). Attention must be given to selecting the right equipment, the right size, and the right contractor.