Concrete and ICF buildings provide a key element in control of the indoor environment and air quality. Never before has a building envelope been able to be constructed, with such ease, and with near zero infiltration rates. This results in a building which can separate indoor and outdoor air volumes. Effectively, the building functions as a “plastic bag”.
Air Exchangers Can Provide
Superior Indoor Air Quality
Reduced Respiratory Issues
Better Humidity Levels
Lower Spore Counts
Higher Oxygen Levels
Infinite Air Flow Control
I do a lot of forensic investigations on ICF homes, and what I’ve often found is that inside, they have higher mold counts and lower air quality than outdoors.
These contaminants come from many different sources. Cleaning products, household chemicals, or paints stored in the utility room which can produce high localized concentrations of dangerous air born contaminants. Dust, pet dander, and cigarette smoke also accumulates unless properly vented to the outside.
Luckily, it’s easy to eliminate these pollutants. Air exchangers, Energy Recovery Ventilators (ERV) or Heat Recovery Ventilators (HRV), can help ensure that you and your family have a healthy indoor air quality.
HRV/ERV technology is typically utilized to control humidity, and almost all installations include humidistat’s, or other air quality sensors to control indoor humidity and/or air quality levels.
Simple activities, like bathing, can raise humidity throughout the home to levels which readily support fungal growth, if not properly vented. Furnaces, gas stoves, and even houseplants can create excess humidity or contaminates. Spring cleaning with bleaches and chemical solutions, which are spread over large surface areas and evaporate quickly into the air creating “spikes” in indoor air contaminate levels.
Air exchangers also help by moving air within the structure, which serves two important functions. First, it reduces localized elevated humidity and/or contaminant levels. Smaller enclosed spaces such as closets, baths and laundry rooms, tend to have elevated humidity levels comparative to areas such as second bedrooms. Secondly, air circulation helps avoid the “heat and humidity stack effects.” Heat and humidity rises, so two+ story ICF homes sometimes end up with top floor temperatures 10 degrees higher and humidity levels 30% greater than the lowest floor level. Properly ducted air exchanger can help ensure the entire home has adequate air distribution to alleviate such issues.
If the structure has an airtight roofing membrane (commonly installed with ICF buildings), air exchangers also play an important role eliminating carbon dioxide buildup. As a basic human requirement, a fully sealed, airtight environment requires about 0.1 air changes per hour, based on approximate air volumes in modern housing. Code requirements dictate a much higher 0.3 air changes per hour on average. As the primary heat loss of a total ICF building is the air infiltration, lessening the effect of heat loss/gains is very important. Utilizing HRV/ERV technology can effectively get back up to 70% of this direct loss.
By using air exchangers to replace stale inside air with fresh outside air, which can easily be further purified with air scrubbing and/or filtering, we eliminate contaminants, reduce humidity, improve air circulation, and ensure carbon dioxide does not build up to unhealthy levels.
Mark Ross owns Architectural Residential Technologies, Inc., he can be reached through the company website www.arit.com.