We had a rear extension done and behold, the living room has gone dark. If it is sunny outside it is fine, but if it's overcast it stays dark most of the day. We have a side window that brings some of the light, and above that window is a skylight that also contributes. I have tried a mirror and it doesn't work because it's flat and doesn't reflect anything. We can't add a window on the sides of the living room because it's exterior and will destroy the house shape and it's complex.