We heartily applaud the Green Building movement's focus on environmental sustainability and energy efficiency.
However, weather-tight, energy efficient construction can solve one problem while creating another problem: inadequate ventilation.
The result? High levels of indoor air contaminants — including carbon dioxide, cleaning chemicals, cooking fumes, and noxious chemicals produced by off-gassing of carpets and upholstery. Often, the most obvious warning sign is constant winter moisture condensation on the interior side of window panes.
Besides being an indicator of poor ventilation, excess moisture can lead to mold growth and window frame deterioration. Windows can even rot and warp, requiring replacement.
Unfortunately, local building codes have not caught up with new green building technology. Commonly the only code requirement is the installation of a damper-controlled fresh air vent. A vent is an inexpensive and easy way to satisfy building codes, but it doesn't work well to ensure fresh, clean air.
A better solution is the installation of an air-to-air heat exchanger. This equipment mechanically exhausts indoor air, while bringing fresh outdoor air inside. An ingenious energy efficient design allows outdoor air to be pre-warmed in winter and pre-cooled in summer before being added to your indoor air.