Indoor Air Quality and Ventilation

A fresh way to look at savings

The most efficient, high-tech way to provide good indoor air quality is either a Heat Recovery Ventilator (HRV) or an Energy Recovery Ventilator (ERV). Go to our Save Money & Energy section to see our ERV and HRV incentive programs.

Both provide fresh, outdoor air while also recovering the most energy possible from outgoing air. The recovered energy is used to heat the air entering the building, reducing costs and making the whole system operate more efficiently.

Both types of ventilators are ideal for buildings that are sealed for energy-saving purposes. Although tightly sealed buildings are good at reducing energy costs, they are not good at providing good indoor air quality.

In fact, without some kind of ventilation strategy, a sealed building quickly becomes a “sick building” in which people feel sick or lethargic because the air they are breathing is stale and dry.

HRVs and ERVs can capture up to 70 to 80 per cent of the energy in air that is exiting the building. The HRV captures only heat; the ERV captures heat and moisture.
In either case, the captured energy is mixed with incoming air at a ratio that is ideal for the building and the seasonal weather conditions to provide optimum air quality at the lowest possible cost.

Building operators often choose an ERV if they live in an area with consistently cold winter weather. It captures some of the water vapour in the air, so there is less water in the vapour to freeze and lock up the core and exhaust vent to the outdoors. This can happen with a HRV because all the moisture in the air is exhausted outdoors.

The core of the heat exchanger in either system usually is made of aluminum, resin-impregnated paper, plastic or a combination of all three. Plastic and aluminum are relatively good heat conductors and prevent the transfer of water vapour and contaminants from entering the incoming air. They also tend to last longer than other materials.

Properly designed ventilating systems should be able to move at least 1/3 of an air change per hour (ACH) or 15 cubic feet of air per minute (CFM) per person.