Don't recommend storing wine on top of the fridge due to the heat generated. I know this has been discussed here previously, but I just googled and found this:

DON’T: Store your wine on top of your refrigerator.

Although convenience is important, you have to also think about keeping the wine’s integrity intact. On top of your refrigerator may seem like the most logical place to keep your bottles (I can’t tell you how many houses I’ve walked in to and seen just that), but it is one of the worst places in your home for 3 reasons. First of all, think of all the vibrations your fridge gives off when the compressor cycles on, when it cycles off, when the ice maker spits out ice, when you’re using the water dispenser, etc., etc. Without getting too deep into chemistry, vibrations alter the processes happening in your wine, affecting the taste and aging process. Secondly, your refrigerator gives off heat. With a compressor and other internal components working hard to keep the interior cool, a significant amount of heat is given off. Have you ever felt the top of your refrigerator? It’s warm. Lastly, the top of your refrigerator is probably very close to your light fixtures. This may not be the case for everyone, but if it is true, this definitely is not a good place for your wine to be. Light bulbs give off lots of heat and can prematurely age your wine.

I'd look for a different location. We have a wine rack on the wall that IMO doubles as art.

If you want to do the X's, make sure you know how much (or how little) wine you can store in them. The X-type storage is not very space-efficient. But if you do want the X's, they're usually based on a square -- so height=width.

A shelf-type wine rack would be more space-efficient. But that's just the opinion of someone who wants to store as much wine as possible!

What nhbaskets said - please don't store wine over a fridge.

To be specific, we are NOT talking about the wine lattice, but the solid wood wine X cubes? Like the ones on the end of this island?

Not the lattice ones in the middle of this design?

The choice of size is dependent on the cabinet line. The smallest cube is usually 15”x15”. The largest is 18”x18”. I have seen some 24”x24” in some lines. The X’s are also generally done as literal cubes, neither 12” deep, nor 24” deep, making them difficult to integrate into a design plan well without some skill. Unless the line offers customizations that would allow other dimensions. If stacked, you have to plan as to how to finish of the seam between them in an attractive manner, etc.

But, as others have mentioned, above the fridge is a poor location, even if you drink the wine rather rapidly. A better choice for over the fridge would be cookie sheet storage or a roll out tray for seldom used vases and other items.

I was thinking it might be a bad place for storage because of the heat. Visually I like the design of having it above the fridge. This is for a spec house, so they may not even be wine drinkers. I was actually thinking of the lattice squares. I may rethink this idea though.