# Computing the average hours of sunshine at given location&orientation

I made it my geeky aim to see which of two flats that we are considering moving into is sunnier. The first flat faces S and the second faces NNW; both are at the same height above ground and have similar terrain (buildings/trees) around.

Conventional wisdom would suggest the S-facing one is (much) sunnier, but I am not sure if this is really so, since I don't think it is the case that the Sun, when it's above the horizon, spends most of its time in the Southern-hemispace/hemifield.

Furthermore, I'd like to get a more quantitative estimate of how much direct sunlight each flat gets per day (averaged across seasons). How can I use tools available on the Internet (probably GoogleMaps-based) to find this out?

My only solution to date was to generate Sun trajectories (elliptics) for each flat, using the SunCalc.net website; these suggest the NNW-facing flat hardly ever sees the sun, except around the summer solstice. Is this a reliable estimate, or can anyone suggest another way to solve this riddle?

• I'd go with conventional wisdom here. South is sunnier by a long way. But could you clarify what is meant by "sunnier" For example does the angle that the sun makes with the window cunt, or is it just the length of time that the sun is shining on the window? – James K Dec 22 '17 at 20:06
• Thanks James. I don'tthhink the angle would be a factor, since the two locations are only a few km apart. It's really the amount of time that sun rays (assuming it's not cloudy) would flood the room that has the given orientation. So it is, after all, the case, that during the day (averaging across seasons), the Sun spends more time in the Southern half of space than in the Northern one? – z8080 Dec 22 '17 at 20:25