Slideshow: Stand-Alone, Recovery Ventilation
A stand-alone recovery ventilator pulls in fresh outdoor air while exhausting stale indoor air. The air streams pass through opposite sides of an exchanger core. Ideally, the two air streams do not mix at all but do exchange heat (both ERV and HRV) and moisture (ERV only). In winter, then, the outgoing warm air gives up some of its heat to the incoming cold air. The warm air also has more moisture and in an ERV, some of that moisture will migrate to the cold, dry air coming into the house. Illustration by Tim Healey.