While your freezer doesn’t have a light (or is perhaps just burnt out; you should check! ;-)), in fact, many freezers do have a light or lights.  As to why it seems somewhat common for a lot of freezers not to have lights, there are a variety of theories out there.  Unsatisfied with the explanations I was finding, I went ahead and asked someone in the industry, a long-time refrigerator technician, Ed Dougherty.  His response was in-line with one of the more plausible explanations I’ve subsequently read and is as follows (paraphrasing):

It all comes down to cost/benefit and features.  While it’s not terribly expensive to add a light, sealed fixture, switch, wiring, etc. relative to the cost of the whole unit, it does cost something and manufacturers want to save every dollar they can in the cost of manufacturing their product. Studies have shown that people don’t open the freezer nearly as much as they open the refrigerator and certainly not as much for “browsing”.  Ice-cream sandwiches and similar items aside, when people open the freezer, they are generally going to be looking at getting something out that takes some further preparation. So the kitchen light will probably be on anyways. Thus, the benefit of having a light in the freezer is much less than in a refrigerator that often gets raided at night, to the point that manufacturers would rather save themselves the money of putting one in, as most people don’t really care or notice whether their freezer has a light or not.

Think about it, do you know without looking whether your freezer has a light and, if not, have you ever found yourself wishing it had one? (Note: I didn’t know and had to check!  It did but it was burnt out and I never noticed!  Further, last time my refrigerator light went out, I felt something was off immediately, but couldn’t put my finger on what exactly until that very night when I didn’t have the light on in the kitchen and opened the refrigerator door.  I then realized the problem instantly with the refrigerator, but never noticed with my freezer.  You win this round Ed and refrigerator/freezer manufacturers.) 🙂

A lack of light in low end models also provides a low-cost, easy to add, feature that can be tagged on to help up-sell certain people to a much more expensive model, with salesman convincing you that you should care whether it has a light or not, even though you probably never cared or thought about it before.

Another popular explanation along the same vein, and that seems reasonable enough, is that with non-automatic defrosting freezers, particularly with older, low-end models, there is the problem of ice crystal build up from the humidity of the air introduced when opening the freezer.  This not only reduces the efficiency of the freezer itself, but also would reduce the utility of the light or even obscure it altogether, making it pointless (and hence the benefit vs. cost plummets even further).  Once self-defrosting models were introduced in the 1950s, this wasn’t an issue anymore, but the tradition of not lighting the freezer remains thanks to the benefit the freezer light provides still being low enough, relative to the cost, that manufactures didn’t want to have to pay for it.  As Dougherty mentioned above, it also makes a cheap, great sounding, though with typical use not terribly useful, feature to try to get people to buy a more expensive model.

Other popular explanations include:

• Freezers tend to be more densely packed, so a light isn’t going to be helpful in terms of lighting up most of the freezer. (I didn’t really like this explanation as there are numerous, easy ways to get around that potential problem.  Further, not all freezers are front opening, many open from the top or are a drawer unit that is pulled out, so how densely packed things are isn’t going to make a difference here in terms of blocking light. Yet there are many such freezers that don’t include a light).
• The old style incandescent lights would shatter with heating/cooling as it goes on and off. (I didn’t like this one as lights made to handle this type of heating and cooling have been around for a long time, though perhaps in the early days a potential extra cost of bulbs that could handle this may have further skewed the cost/benefit ratio.)
• In top freezer, front opening models, the overhead light is at a better angle to the freezer to allow sufficient light compared to the refrigerator below it, so the light is pointless. (I didn’t like this one because plenty of light gets in on side-by-side units, both with freezers and refrigerators, and bottom pull out units or top opening box freezer units would get even more light. The point being that all of them would get plenty of light as long as the room was adequately lit.  So this explanation is kind of a non-point, which ultimately just goes back to the cost/benefit argument.)
• An incandescent light in the freezer will generate too much heat, making the system extremely inefficient. (Absolute nonsense.  I can only assume these people think the lights in refrigerators and freezers stay on 24 hours a day and are extremely powerful bulbs.  For front opening models, they must also not fully appreciate how quickly the cold air is lost as you stand there with the door open and ponder whether to have the Marie Calender’s chicken pot pie or lasagna for dinner.) 😉