By now we all know that manufacturers often overstate the virtues of whatever it is that they’re selling. Think about the EPA mileage estimates plastered to the window of the last car that you bought. How do these numbers stack up to your real world experience? Well, it’s the same deal in the world of appliances. Size ratings aren’t all that indicative (in an absolute sense) of how big an appliance really is. This is particularly problematic when you start talking about refrigerators — unlike mileage estimates, where you can use the numbers to make relative comparisons amongst models, you can’t necessarily rely on size ratings as a relative measure of usable space in the wonderful world of refrigerators. Let me explain…

On the surface, it seems like it’s easy to pick the fridge with the most storage space — just check the label and pick the one that offers the most cubic feet. Right? Well, not really…

As it turns out, manufacturers are required to calculate volume by measuring the length, width, and height of every part of the refrigerator (and freezer) box and doing the math (length x width x height = volume). But they include space taken up by shelves, hardware, and that annoying indentation in the back side of the door that accomodates the water and ice apparatus.

The problem here is that side-by-side and top-mount refrigerators differ substantially in the proportion of this total volume that is actually usable. In fact, according to numbers from Consumer Reports, only about 65% of the total volume of a side-by-side unit constitutes usable space, whereas 78% of the total volume of a top-mount is usable. (I would assume that bottom mounts are similar, but I don’t know for sure.)

So what does this mean for you? Well, it’s important to keep this difference in mind when appliance shopping. After all, based on these numbers a 22 cubic foot top-mount refrigerator is every bit as ‘big’ as a 25 cubic foot side-by-side (and maybe even a touch bigger). Assuming that each unit is equipped with similar bells and whistles, however, the former will always cost a good bit less than the latter.

Setting aside the price difference, this huge difference in usable space is one of the main reasons that we were so enamored with our GE Artica 24.6 cubic foot top-mount refrigerator. Given the size of our family, space is at a premium for us, and we can’t afford to sacrifice capacity for the ‘convenience’ of a side-by-side — I set that off in quotes because I frankly don’t get the appeal of the side-by-side configuration even though many swear by them.

And what about bottom-mount refrigerators? This is an entirely subjective argument, but here goes… First off, I really don’t get the appeal. I understand the argument about not having to bend down to get into your fridge, but something just doesn’t seem right about them (I’m a creature of habit, I guess). But more importantly, putting the freezer on the bottom means that our kids can’t get stuff in and out of the fridge, so we’d be at their beck and call everytime they wanted a sip of milk. And with four kids in the house, that’s almost all the time.

Anyway, the next time you’re in the market for a fridge, keep in mind that comparing capacity estimates across styles isn’t an apples-to-apples sort of thing… If you want more bang for your buck, you’ll come out way ahead by steering clear of side-by-side refrigerators.