With the introduction of the 2021 PartL building regulations an additional field was added relating to Foundation Area:
If an appropriate figure is not entered in this field, your Target Energy Rating will be distorted and may appear as zero. This is because the notional building uses this area to assess the potential area for PV, and will displace electricity. For example:
Should you be unsure as to what value to enter then the NCM Modelling Guide (available from the NCM Download section - link here) or your scheme provider would be best placed to confirm.The guidance from the NCM Modelling Guide is as follows:
Note should you wish to measure the footprint of your building/rooms, you can easily do so in Energy Simulator by using the Distance function: