My advice here is to buy the best LED lights you can afford.
Something like Photo-Bio MX would be perfect.
If you choose to go with traditional heaters or High Intensity Discharge (HID) lamps, you’ll need two bulbs.
Most modern lights are interchangeable, accepting both Metal Halides (MH) for vegging and High Pressure Sodiums (HPS) for flowering.
Depending on how well you can cool the tent (AC is an option) and your particular climate, you can use up to 1000 watts.
Modern HID’s are adjustable by both wattage AND voltage (110v-220v). If you decide to add more watts later you simply buy a different bulb.
You need the tent to stay below 85 degrees with the light on. Cooler is better, that’s the MAX.
You can always leave the tent open and use fans to direct cool air in and hot air out.
Hanging a thermometer by the plant tips will let you know if the lights are too close.
The temperature at the leaf tip should be 80 degrees or less.
Some growers change the light cycle to give the growing plants a rest, adjusting to either 18/6 or 20/4 (light/dark).
LEDs can be kept closer as they don’t give off nearly as much heat.
Tip: Don’t forget to use your timer. This little appliance will save more heartache and effort than pretty much anything else you will buy.
Mess up the light cycle and you could end up with hermaphrodites. Hermies lead to pollinated buds, full of seeds. Not cool!