Help with Lights!!

I want to go with a 400w HPS light but I am not sure about the electricity.

I was going to get this one:

400 Watt HPS

Which looks like it just plugs right into a wall outlet. I can't find out if these lights are for 120 volt or 240....will a regular 15 amp/120 volt outlet work?

You have to make sure you get a system with ballast, fixture and bulb. That *will* plug into a regular outlet. The page you linked has these components and full systems.

Ok thanks, that is what I thought!
Now one more thing..

I ordered a 400 watt MH light:

http://www.elights.com/40hpsplangro.html

With a HPS bulb on accident.

Needless to say I have to fix this order or cancel. Now I am looking at opinions for which lighting to use.

My grow space is 6 feet wide, 21 inches deep and 8 feet tall. I have been watchign temps in there and right now with no lights its between 72 and 78 degrees. I am not sure if a HPS will work with those temps...I need help ASAP!

Regular 110V (You can see the regular plug on the ballast image if you enlarge).

A 400 watter will be fine on the circuit as long as you aren't running other heavy draws on it. When you get into the 1K, then you need to really start watching.

There are some 220V 400 watt ballasts out there (and some that will run on either), but 110V is far and away preferred and more plentiful.

well, it's going to get toasty, so you'll need some inline fans for temps and also for feeding co2 to your plants. you can reduce the heat input to your grow room by selecting a fixture that :

1. has a remote ballast so you can keep it outside the box
2. has the light shielded by glass or a tube (ala cool tubes) and allows cooling through the fixture.