If your tank is going to be kept inside, the best way for your Dragons to enjoy heat is with a incandescent bulb or a spotlight. Do not use a house light bulb. (you can by these at all pet shops) Place the bulb in a reflector type fixture, make sure the fixture can handle some heat.
Then place the fixture above the basking spot or hot spot located at one end of the tank. In bigger tanks you can have two hot spots or one in the middle, the reason for that is if a Dragon wants to cool off or get a little warmer they could do so by moving around differant parts of the tank.
The bulbs wattage should create a temperature of 90 to 105*F in the section closest to the light. In a 25 gal tank use a 30 to 40 watt bulb, in a 55 gal tank I would use a 60 watt to 75 watt bulb, in a 75 gal 100 watt. To measure this I bought a little gage at radio shack $15 and placed it on top of their basking log.(its important that its not to hot or to cold inside their tank)
The temperatures in the tank at the hottest spot should be 100 to 105, the cooler part should be around 80 to 90.(at night temps can drop to 70 to 75 when the lights are out)
Be sure you place your light and heat bulb fixtures on the screen top far enough away from your Dragons so they won't get burned!
What I also like to use are infared bulbs. I have all my heat bulbs and lights on timers, so at 9:00am my lights go on at 10:00am my incandescent lights go on and at 2:00pm my inferared light goes on and what that does is give the Dragons a more natural like heating process.
Heat pads that stick to the bottom of the tank help bring the temps up inside but make sure your substrates(stuff at the bottom)can handle it.
Bearded Dragons are very colorful and what keeps them healthy and colorful are lights called UV-B bulbs.
The reason why Dragons need such lighting is because they need what the sun gives them vitamin D3. Full spectrum fluorescent bulbs put out UV-B and UV-A which have positive phychological effects and stimulate activity, feeding and
they may play a role in thier reproductive behaviors. These bulbs are a little costly but you need one per enclosure. Its recomended that you replace them once a year. Just like the heating bulbs they should be set on timers, 14 hours of light a day and during the winter months set it for 10 hours of light.
Direct sunlight is good for beardies if your in the proper climate for them, but if not they'll do just fine with the full spectrum lights. Back to the vitamin D3 if your Dragons don't get enough of this they can die, so along with the lights they also make a vitamin supplement that you put on their food.(see food section)
When reading this section remember where your Dragons are from and what type of climate they would live and thrive in!!!!