Also in Santa Monica how the hell do they keep the building cool in summer?
Went in today myself (awesome!). In addition to many answers you've gotten, like the design being high and wide:
(1) Santa Monica, being near the ocean, is typically some 10 degrees cooler than the rest of L.A. So if it's 90 degrees in L.A. it's 80 in Santa Monica. Also, because S.M. is on the ocean, it gets far more fog and cloud cover. The Promenade is some three blocks from the ocean. So while there is a lot of sunlight during the year (it's California), S.M. is, relatively speaking, less relentlessly sunny than other areas of Southern California.
(2) the glass ceiling panels are tinted--i.e. they're blocking out a lot of the sunlight.
(3) the front windows won't get any direct sunlight coming in as the store faces west. That means only the setting sun could come in through the front of the building and buildings across from the store prevent that. Which is to say, the only direct sunlight will come in from overhead (see #1)
(4) I asked one of the sales guys about the heat issue and he pointed out to me a whole perforated area of wall below the display tables. The building has a system of air that comes out from the lower walls and circulates over the floors. He assured me that rain or shine, the building will stay at a comfortable temperature year round. It's very highly and ingeniously climate controlled.