Exhaust Ventilation Systems

The air within homes can become stale from
moisture, odors, and pollutants that penetrate the
home or are generated internally by human activity
and out gassing from building materials and
furnishings. A constant supply of fresh, outdoor air
can provide greater assurance of good indoor air
quality and improved comfort.

In most homes, ventilation is provided accidentally
when air leaks through the building envelope.
Accidental ventilation is unreliable because it is
dependent on a pressure difference between indoor
and outdoor spaces caused by temperature or wind
variations. Too much fresh air often enters a house
during cold weather causing uncomfortable drafts
and high heating bills. Not enough fresh air may
enter during mild weather which can lead to poor
indoor air quality.