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In today’s tightly-sealed, energy efficient houses, a source of mechanically introduced fresh air is vital to maintain indoor air quality. As residential construction methods become more air-tight to conserve heating and cooling, airborne particulates and contaminants can accumulate to harmful levels never seen in the drafty, well-ventilated homes of the past.  Today, the gold standard for mechanically introduced fresh air ventilation is the ERV (Energy Recovery Ventilator.)

One-Way Downsides

Conventional exhaust-only or intake-only ventilation has built-in drawbacks.

  • One-way exhaust fans move stale air out without introducing an equal volume of fresh replacement air. This depressurizes the interior of the house, causing uncontrolled amounts of unfiltered outdoor air to be sucked indoors through tiny structural cracks and gaps, as well as from potentially contaminated zones like the attic or crawl space.
  • Intake-only ventilation systems add fresh outdoor air to the HVAC system return duct. Although the system dilutes airborne contaminants, it also slightly pressurizes the house, forcing moist indoor air into wall cavities as well as the attic. Accumulated moisture in these areas promotes mold growth. Also, in humid climates, intake ventilation systems introduce excessive outdoor humidity into the indoor environment.

The ERV Advantage

An ERV (Energy Recovery Ventilator) incorporates dedicated small-diameter ductwork to remove stale air from areas like the kitchen, bathrooms and utility rooms while adding filtered, fresh outdoor air to bedrooms and family rooms. ERV’s combine three mechanically introduced fresh air functions into a single energy-efficient unit.

  • Twin fans in a central controller exhaust stale indoor air while inducting fresh outdoor air in precisely the same volume, preserving neutral indoor air balance. This ventilates the house without depressurizing or over-pressurizing the interior, promoting healthy air quality.
  • A heat exchanger incorporated in the central controller extracts heat from the warmer air stream and adds it to the cooler air stream. In winter, this prevents household heat loss while inducting cold outdoor air. During summer, heat removed from incoming outdoor air avoids increasing the home’s heating load.
  • The central unit also incorporates a core that extracts water vapor from the moist incoming air stream and transfers it to the outgoing air stream. In humid climates, this reduces excess humidity brought into the home when ventilating with fresh outdoor air.

Let the professionals at Paschal Heat, Air & Geothermal explain more about the technology of ERV (Energy Recovery Ventilator) and the benefits of balanced, mechanically introduced fresh air ventilation.