"Does it take more energy to cool a house in which the AC has been off all day, than to keep the AC running at, say, 85 degrees during the day?

No. Cooling a hot house down at the end of the day always takes less energy than leaving the AC running all day, even if it's running on a high setting."

If you have a typical red brick house, like the type seen in the UK, why not just hose the house down with water and let evaporation take some of that heat energy?

Black out blinds also do a good job at keeping the infrared heat energy out of the property so you dont need to run AC units for as long or on as high a setting. These same black out blinds also do a good job of keeping heat in during the winter months. Better than triple glazing or double glazing with expensive gas between the panes in my experience.

Handy database though, shame these integrated fuse boards that are fitted to houses couldnt measure the power consumption and run direct lines from the fuse board to the socket, instead of having to have ring mains. That way these fuse boards could also become a central controller killing the power to a socket, which would further reduce the standby power consumption of various devices.