Growbox advice/ Lighting

Alright so I'm setting up a growbox 4'x2'x3'4" (LxWxH) meters for about 3 or 4 plants max of northern lights or white widow strains. I built into the walls 2 computer fans (1 for intake and 1 for out) each with carbon crubbers attached. The walls will be either painted white or lined with tin foil; opaque side as the reflector. The box itself is made out of cardboard and thus I'd feel much better and safer if I could use only cfl bulbs. My major concerns are my electric bill and heat emissions. Would 6000-8000 or 8000-10000 lumens be enough or can and should I still use hps lighting for a box this size? I have regular, standard household light fixtures so cfl bulbs would be ideal although I realize I'd need a few bulbs. Would Hps lighting be safe? easier with less bulbs? How many lumens would I need for 3, 2.5 feet tall plants start to finish? Again, I dont want extreme heat nor extreme wattage consumption. Any positive advice would be appreciated. Thanks.

DON'T USE A CARDBOARD BOX! You're setting yourself up to burn your house down. Also there is no need to have a carbon filter on the air intake only the exhaust. Buy a tent off amazon for <$100 but don't use a cardboard box. If you can afford it use an HPS, or ceramic metal halide.

Since your height is limited I would use either CFL or t5 setup. HID lights need a lot mroe space due to heat issues. Heat is something you probably won't want to deal with. you could run a 4' 8 bulb t5 setup and literally light up your whole grow room! If you can fit it in there. I have a 2x2 grow area and i have a 2' t5 setup in there.

Here is something like I'm talking about. The only thing is that i have a tent so my sides can get a little pushed out by the light so it's not an issue .http://www.htgsupply.com/Product-GrowBright-4-Foot-8-Lamp-High-Output-T5-With-Choice-of-Bulbs.asp

For the most part 10k lumens will probably not be enough. you should ADD LEAST aim for 20k minimal. Don't cut your self short on light it's not worth it. The more Lumens you have the bigger and better your plants will be. As for your electric bill you won't add too much probably like 25 bucks a month if you get that 4' t5 setup.

As for Tinfoil... NO! I say NO!. lol stuff isn't good for reflecting it creates heat spots. buy some mylare it's relatively cheap and will save you a lot of effort in the end. But painting it white works just fine.

Edit: also t5 put off little heat so you can keep them very close to your plants

I agree with tity shit. t5 is the way go. even a 4' 4 bulb fixture will give you over 200w and 20k lumens.

With CFL's a cardboard box will be fine, check out my first grow and Concord Dawns last harvest in the CFL section. There are plenty of people using cardboard boxes just search around to get a good idea of how much light and ventilation you'll need.