I've been using this model for about 2 years now with fair success. There's some things I like and some things I don't. Because of that, I've ordered the HF3510 (the short round one) from Woot!.
First off, the general concept is that these lights have 20 brightness levels. You choose what max brightness you want it to ramp up to and then, about 30 minutes before your chosen alarm time, it starts stepping the brightness up incrementally until it reaches that predetermined max setting 30 minutes later. It takes a few days of experimenting to find the correct brightness for your own best wakeup. If you have it set to max at 20 (brightest possible), and you wake up the next morning at 17, you back off the max setting to 17 for the next morning's alarm. The goal is to set it so that you tend to wake up from the light about the same time that you hear the audible alarm begin to sound. This helps simulate the visual cues that sunlight normally provides, though on your schedule rather than on the ever-changing sunrise times. It's not as jarring as having the room lights suddenly switched on or having a lamp on a timer.
Second, the audible alarms basically are either nature sounds (which I don't use) or the FM radio. In both cases the sound volume ramps up to your preset volume max over the course of about 5 seconds or so (give or take). Thus it's not audibly jarring like a normal radio alarm would be.
Third, I've noticed some people commenting and wondering about SAD/Seasonal Affective Disorder and this unit. The light frequency required to combat SAD is on the blue end of the spectrum (thus the "blue light" that someone mentioned in a comment). The HF3470, and judging from the pictures the HF3510, creates a yellow-orange tinted light. I'm not sure if this is intentional, sort of like an orange sunrise or something, but it is definitely NOT the correct wavelength for SAD treatment. However, I suspect that the gradually increasing brightness may result in less abrupt awakenings and may help some with energy and mood. You're still gonna want a SAD wavelength light box if you really have SAD.
So, on with the actual review.
The HF3470 is actually more like a table lamp than an alarm clock. It uses a replaceable halogen lamp (of a particular type, not just any lamp) to gradually brighten to a preset level which helps your brain gradually come out of deep sleep and wake up. It includes an FM radio that, when turned on, gradually ramps up the volume over a few seconds.
This unit can also be used as a regular lamp as well as a regular radio, with each function being able to be independently turned on and off.
On the side of the unit near the base, arranged vertically, are most of the controls. There are three buttons for the lamp (on/off, + brightness, and - brightness) and three buttons for the radio (on/off, + vol, and - vol). There is also a short metal toggle switch that serves as the on/off toggle for the alarm and can be depressed further downwards for a 9-minute snooze.
On the front of the unit is the LCD display plus the buttons to set the time, set the alarm time, and change the radio station. These buttons are not exactly intuitive, but are no worse than most clock/radios.
The light output of this is very orange-yellow in caste. This is MUCH more yellow than most incandescent light bulbs and appears to likely be intentionally skewed towards that end of the visible spectrum. At it's lowest setting, the lamp is about as bright as a small candle. At its brightest, it is perhaps equivalent to a 40 watt incandescent.
For the HF3470 model, here's the pros/cons:
- It really does help you wake up gently if used properly.
- Nice bonus of helping you not stumble around in the dark trying to hit the room light in the morning when the alarm does go off.
- Radio reception seems fair to good.
- Small amber LCD time display is not very bright so doesn't light up the whole room like a laser light show as many alarm clocks do.
- Only one alarm time setting. Thus if you're in some line of work or in college where you don't get up the same time every day of the week, you'll be changing the alarm set time a lot.
- Difficult to change alarm time settings. The buttons on the front are small and not very easy to use. I'm sure you can get faster at it, and if you do it a lot you won't forget how, but it's still going to be annoying.
- Kinda huge for an alarm clock. This thing takes up a footprint about the size of a typical table lamp. It's very tall, for something that goes on a nightstand, and has a pretty wide base.
- Uses halogen bulb. This bulb will need to be replaced (though I haven't had to do so in about 2 years of usage b/c I usually get up and turn the light off fairly quickly). This may become a problem as incandescent/halogen bulbs are now federally outlawed. I also checked on the price of one of these replacement bulbs two years ago, and you can only get them from Philips and they were very expensive (I think around $60). The legal issue may be why this version of the wake up light has been discontinued (I hear).
- Since this uses a halogen bulb, the unit can get pretty hot, especially the top of it. The manual instructs you not to place anything over the top (where there are vents), but if the light has been on for 30 minutes or more, the top can be too hot to touch.
- The color of the light is very unnatural. Sunlight, even at sunrise, is much more white than this light is. Thus I've found it less than ideal vs. actually waking up to a sunrise. It also makes it difficult to use as a table lamp, particularly to read by at night in bed.
- The sound quality is quite poor. It's not recommended to listen to any music over the FM radio as you'll struggle to even make out what it is that's playing. Talk radio is adequate, so I tend to have it set to NPR.
- No independent settings for brightness or volume vs. the wake-up settings. If you change the brightness level and forget to change it back, it remains at whatever the last setting was. So you can't have it on max brightness to use as a lamp and also leave it set for 15 as the wake-up brightness.
- Due to the relative dimness of the lamp, even on maximum, if you happen to be turned in bed with your face away from the light, it loses a lot of the benefit since you may not "see" the room getting brighter.
- The biggest shortcoming is how expensive it is, even on sale. There's no reason for this to cost more than about $40 or so, especially given its limited functionality.
One thing that anyone who wants to use this should absolutely do is get their sleep/wake cycle set to the same time every day, even if you don't need to get up for anything in particular the next morning. If you don't go to bed at the same time and get up at the same time every day, you're sleep cycle can get pretty messed up. As such, it becomes much easier to sleep through the gradual light increase and have to depend on the radio/audible alarm to wake you up. This will negate the whole point of this type of alarm clock.
All in all, its positives will outweigh its negatives for many people. I particularly find it handy in the winter, even here in the South, where I am often waking up long before sunrise in the depths of winter. It does help better than just waking up in a dark, cold room, and the ramp-up volume on the radio is a nice touch. There's lots of room for improvement, and I expect that Philips or a competitor will eventually execute this concept much better.
I'm going to try the newer model and see if it's any brighter (it's supposed to be) and if it has a more natural light color. More importantly, though, having LED bulbs should mean they will outlast the rest of the alarm clock and I don't ever have to worry about replacing the bulb, especially if they can no longer sell the halogen bulbs.