Advanced heat pump dehumidifiers minimise ventilation waste.

Energy lost through ventilation becomes increasingly important as building insulation levels improve. Describes application to this problem of heat pump dehumidifier which transduces latent heat of moisture in cool damp air into sensible heat of warm drier air. Describes laboratory prototypes which combine sensible heat from counter flow heat exchangers with heat transfer properties of a heat pump. Claims such systems perform twice as effectively as conventional equipment and offer a new approach to ventilation losses.