When producing the EPC i get an error saying negative SAP wall area, check my heat loss perimeter. I have checked and it is correct so why?!
You will receive this error message if the RdSAP calculation deems your Heat Loss Perimeter to be incompatible with the inputted Total Area of the property. Check that the value entered for the Heat Loss Perimeter on each floor is accurate and realistic. Check that the decimal point is a full stop not a comma. Make sure you have included any sheltered walls as part of the Heat Loss Perimeter. If you are positive everything entered is correct the problem may be the Glazing Area selected. If you select this as Typical, the software assumes a particular area for the windows that is deducted from the total storey area of the property. If you wish for the window area to be completely accurate then you should select the Glazing Area as either Much Less or Much More than Typical so that you can enter the specific dimensions of each window in the property.
