Light boxes for Seasonal Affective Disorder (SAD), have many names, but what are they really? They can be called light boxes, bright light therapy boxes and phototherapy boxes. Not all of these light boxes are created equal, what might work for one person might not work for another. I hope to give you an understanding of their differences and therefore allow you to get the one that will best work for you.

The purpose of the light box is to help lift your mood and easy symptoms of SAD, along with helping to adjust daily sleep cycles. Typically they are used for 30 minutes or more in the morning, shinning directly towards your eyes.

Some light therapy lamps are especially designed for skin disorders, since they emit ultraviolet light. These light lamps would not be safe for SAD as the UV light could damage your eyes. 
The brightness of light boxes varies from box to box, so make sure you know how bright your light is. For example, it may be effective to use a light box that produces 10,000 lux (a measurement of light intensity) 12 to 14 inches from you for 30 minutes each morning. However, using a box that produces 2,500 lux at the same distance may take two hours or more to achieve the same effect.

SAD light boxes are designed to filter out most of the UV light, it is best to find a light box that will emit as little UV light as possible. Typically white light is the standard used in light boxes; however some light boxes use blue light (which is a shorter wavelength). The research seems to show that the blue light might be slightly more effective at reducing SAD than white light. However the blue light may cause more damage to your eyes than white light.

Most light boxes need to be 2 feet away from you to be used properly, so when you are looking for your box make sure you can use it at this distance on a daily bases. The boxes also come in different sizes and shapes. Get a box that will function for you. 
If you need help balancing your sleep patterns than a light box that will simulate dawn would be best. However for SAD you need to be exposed to bright light for a constant 30 minutes or longer.

It comes down to making a choice that will support your needs. If you need sleep pattern balancing then a light box that will slowly increase in intensity would be best. If you are dealing with SAD, then a single intensity light box would be best. I would recommend using a white light box rather than the blue light. Light boxes can cost anywhere from $100 up to $500.