Sap 3. 3 version released 10/08/09. Improved support for mechanical ventilation and heat recovery, community heat pumps plus user interface productivity enhancements.This update incorporates many new features including mechanical ventilation and heat recovery, community heat pump and assumed pressure test. Furthermore windows are now allocated to a wall and the window area is deducted from the gross area. Lastly the living area can be entered and the fraction calculated.