What to do when I get zero heat loss value for the entire property at Step 8?

There are quite a few areas to check. We have listed them below.

Step -1:

If the address is manually filled in Step 1 - the degree day data, altitude, design temperature, and ground temperature fields will be blank. Please ensure that you fill out the postcode and update the address using the "search" icon. When the address is updated this way all the above-mentioned fields will be automatically populated. 






Step - 3 and Step - 4:

There are cases either the room will not have any dimensions filled out or the floor area will have a '0' value. Please make sure that all the rooms have the necessary dimensions filled in.  

Step - 7:

When ever you are using material using the BRE IP 3/90 formula please ensure that the "External Wall" dimension in Step - 3 and Step - 4 are filled in. This is because the formula uses the external perimeter (external wall) and the floor area to calculate a U value.
U = 0.05 + (1.65(P/A)) – (0.6((P/A)²))
Where:
U = U-Value of the uninsulated floor (W/m²K).
P = Length of the exposed perimeter (m).
A = Area of the floor (m²).