Letters

The Cost of Exhaust To the Editor: It was very surprising to find no mention of "air exchanger" systems in Andrew Shapiro's article "Simple Whole-House Ventilation" (8/95). These systems bring in fresh air and exhaust stale air through a small heat exchanger that can reclaim up to 80% of the energy of the exhausted conditioned air. These systems are quite common in Canada, and are now being offered by U.S. manufacturers as well. Their use controls condensation on window surfaces and reduces "sick building syndrome" problems (as would Shapiro's system), but with a much lower energy penalty. Carl Mezoff, AIA Stamford, Conn. Andrew Shapiro responds: It's true that a heat recovery ventilator (HRV) is the best mechanical ventilation system: Not only does it