7/6/2014

The Importance of Heat Recovery or Energy Recovery Ventilation in Energy-efficient Buildings

65% of the electricity consumption and 35% of total energy use in the United States is used in buildings.  Buildings also account for 30% of greenhouse gas emissions according to the U.S Green Building Council.

Homes are making the shift toward more energy-efficient design and construction with greater energy efficiency awareness and building codes reducing energy consumption.  Many building standards and certifications programs have been developed to promote green building.  Some certifications and standards programs include LEED, Passive House, and Pretty Good House. One of the key components of increasingly energy-efficient buildings is to have a tighter building envelope.

Steps such as air sealing and insulating have reduced energy usage and greenhouse gas emissions in buildings.  Tighter homes though have caused increased indoor air quality issues.  The previous generation of leaky houses wastes a significant amount of energy but because they are “leaky,” a continuous supply of outside air is naturally brought into the home.  Today the key is to “build tight and ventilate right” so one lives in both an energy-efficient and healthy home. Energy-efficient buildings need a mechanical ventilation strategy to ensure that airflow is kept fresh and healthy for inhabitants.  Heat recovery ventilation (HRV) and energy recovery ventilation (ERV) systems are ideal choices for homeowners and builders to fulfill these needs.

Carbon Dioxide Dangers

In poorly ventilated homes, carbon dioxide is likely to build up. This stale air can contribute to a number of dangerous health issues for those who live or work in these buildings. Stale air can cause sleepiness and lethargy in those who are consistently exposed to it. In more severe cases, inhabitants may experience symptoms such as asthma, headaches and mental fogginess.

Need for Heat Recovery Ventilation

Most people are familiar with exhaust fans, often found in bathrooms but sometimes used for whole house ventilation as well.  Exhaust-only ventilation systems operate by depressurizing the home.  Exhaust-only systems draw out air from the house while make-up air infiltrates through leaks in the building envelope.   Exhaust fans are relatively inexpensive to install but because of issues such as improper installation and usage in energy efficient construction, mold, mildew and other indoor air quality issues have increased because of poor ventilation in the last several decades.   Exhaust fans have been used as a less expensive alternative to HRVs and ERVs to meet building codes but there are drawbacks. The Indoor Air Quality (IAQ) drawbacks include that unfiltered air is coming in through random cracks and openings in the home.  This infiltration can bring in outdoor pollutants where alternatively an HRV/ERV filters the outside air when it enters the house. If ventilation issues aren’t addressed with a mechanical ventilation system, inhabitants of homes and buildings can begin to suffer health issues like asthma and allergies from built-up mold, dust, and pollen.

Heat Recovery Ventilators (HRV) and Energy Recovery Ventilators (HRV) are the best solutions to minimize energy loss and provide continuous controlled fresh ventilation for the home.  When it comes to the health and comfort of its inhabitant, these systems ensure a continuous air exchange in the home and prevent mold and mildew issues.