All new homes need active ventilation air – in fact, the “tighter” the house, the greater the need for ventilation. Panelized homes (also called SIP panels or structural insulated panels) are no different. SIPs create an air-tight and extremely energy efficient building insulation system offering a continuous R-Value throughout the building. Air from outside cannot infiltrate the walls of a panelized home; therefore, reliance on mechanical ventilation is needed in order to ensure a fresh and abundant supply of healthy air. Maintaining appropriate indoor humidity levels, filtering the air for allergens and air humidification/dehumidification is achieved through a couple of technologies.
In addition to natural ventilation by windows, doors and skylights, your SIP home should have both spot ventilation and dilution ventilation systems. Spot ventilation systems are exhaust systems located in a point source of pollution such as the kitchen or bathroom. Fans properly vented to the outdoors remove moisture, odors, and pollutants that otherwise collect in the home.
Dilution ventilation systems draw outside air into the home through ducted systems while exhausting stale interior air. This exchange of air controls indoor moisture levels and lowers airborne contaminants to create a healthy home environment. Most SIP homes utilize either a heat recovery system (HRV) or an energy recovery system (ERV). Both supply the home with balanced air intake and exhaust. The area of the country in which you build your new panelized home will dictate whether an HRV or an ERV system will be installed.
HRV’s are usually used in cooler, dry climates. A heat exchanger transfers a large portion of the heat (no moisture) between the exhaust air stream and the outside air stream. ERV’s, typically used in warmer humid climates where mold can be a problem, also use a type of heat exchanger system where both heat and moisture are exchanged, keeping the moisture level higher in cold dry months and the ventilation balanced.
During the air exchange process, fresh, incoming air is either preheated or cooled with outgoing stale air; the two airstreams intersect through the heat exchanger allowing much of the heating or cooling energy to be recovered on the inside of the home.
With the use of SIPs smaller, ‘right-sized’ HVAC equipment may be installed, and the HVAC contractor would install the air exchange systems. HRVs/ERVs are typically sized to ventilate the whole house at a minimum of .35 air changes per hour. In order to calculate the size of the system needed for your panelized home, the square footage of the house (including basement) is multiplied by the height of the ceiling to get the cubic volume, divide by 60 and multiply by .35. It is always important to consult local codes for exact sizing requirements. Be sure to discuss indoor air quality in your panelized home with your architect.
Author: Jeremy Bonin
Article Source: EzineArticles.com
Provided by: Digital Camera News