In-line duct silence fans are designed for multiple-task ventilation. This means that you can ventilate multiple areas or multiple rooms with just one fan. For example, you can place inlets over the shower, tub, toilet or vanity in a single bathroom and still use just one fan. In recent years, homes have become more airtight and energy efficient. While this lowers the cost to heat and air-condition a home, it also retains pollutants that can be hazardous to its occupants. One way to improve the air quality of the home is through whole-house ventilation with a Panasonic WhisperLine(tm) fan, which removes "stale" air and provides fresh air on a slow, continuous basis.