Solar gain

What the number is

The figure uses 560 watts per square metre on a south-facing vertical pane, scaled by the orientation you pick, then by the g-value. An opaque external shutter is taken as stopping 85 percent of that gain while fully down. Internal blinds are not given that reduction.

It ignores the lantern, the thermal mass of the floor, and whether you opened the doors at 3pm. Read the extension note before you treat a watt figure as a temperature.