Components of a Heat Recovery Ventilator (HRV)
As shown in the diagram below, a heat
recovery ventilator (HRV) consists of two separate
air-handling systems – one collects and exhausts
stale indoor air; the other draws in outdoor air and
distributes it throughout the home.
Heat Recovery
At the core of an HRV is the heat transfer
module. Both the exhaust and outdoor air streams pass
through the module, and the heat from the exhaust
air is used to pre-heat the outdoor air stream. Only
the heat is transferred; the two air streams remain
physically separate.
Typically, an HRV is able to recover 70 to 80 percent
of the heat from the exhaust air and transfer it to
the incoming air. This dramatically reduces the energy
needed to heat outdoor air to a comfortable temperature.
Air Exchange
The HRV system installed in a home can
change all the air in the house over a three-hour
period. Most HRVs are also equipped with automatic
humidity sensors that increase the ventilation rate
when needed - for instance, when you use the shower
or cooking in the kitchen.
Exhaust air is normally collected from the kitchen
and bathroom areas, where most moisture and odors
are created.
