With all of the recent changes to the energy code, there has been a resurgence in concerns about houses being too "tight." Many people believe that the key to long term building health is the fact that many older homes, with there inherent leaks and drafts allowed fresh air to move through the home. That theory is somewhat true, and actually even more critical now as the new energy code is based on eliminating uncontrolled air infiltration. Proper insulation, use of vapor and air barriers, along with some mechanical ventilation guarantees a healthy indoor environment.
Here is an article from Fine Homebuilding that discusses various ways to achieve a healthy air quality, while still achieving the critical energy efficiency requirements of today's building codes.
