Although enforcement can be inconsistent, Approved Document Part F of the Building Regulations requires all mechanical extract fans in new dwellings to undergo a flow rate test to ensure they meet minimum performance standards. The results must be submitted to the Building Control Body. This testing requirement applies to all types of ventilation systems, including simple intermittent extract fans and whole-house mechanical extract systems with heat recovery (MVHR). As new homes are built to achieve lower air permeability rates, ventilation testing is becoming increasingly important in the drive for more energy-efficient housing. With buildings becoming more airtight, ensuring effective ventilation is essential to prevent issues such as damp and condensation. Part F Ventilation Testing (Flow Rate Testing) should be carried out by a BPEC or NICEIC qualified technician using UKAS-calibrated equipment to ensure accuracy and compliance.