Energy Saving Bulbs

Which energy-saving bulbs are you talking about? Lighboxes had the bulbs built in and as they're either fluorescent or LED, they're already energy-saving. Dawn simulators need to take a bulb that can work on a dimmer, so they can't use LEDs or fluorescent lights (although some all-in-one dawn simulators have been formulated using those, you can't use them if it's the sort where you put in your own bulb).

Traditional dawn simulators, such as the Lumie ones or the Sunrise System one which plugs into a lamp of your choice, have been supplied with incandescent (Tungsten) bulbs, i.e. ordinary high-energy bulbs. These have a bit of a tendency to cause a buzzing noise. There are new energy-saving bulbs on the market which are shaped like traditional incandescents but have a halogen capsule inside. Make sure it's these new ones, they should be marked as dimmable, as opposed to ordinary halogen bulbs. The dimmable halogen bulbs are what I'd call medium-energy, e.g. a 42W is equivalent ot 60W incandescent, and not only are they suitable for use in dawn simulators, they're actually preferred because they don't buzz. Morning Sunrise recommend them for their dawn simulators and I think are going to start supplying them with the dawn simulators as well as selling them on their website. I don't know about Lumie. Incandescent bulbs are being phased out and these new halogen bulbs are the best replacement in terms of light quality, so I'd expect them to become the standard for dawn simulators.