You really can't have "too much" light man. Heat is the problem that you need to avoid when adding lighting.
If you already have the 1000w you are almost certainly going to need a vented hood. A single 1k watt lamp with ballast can raise the temp of an area that small by as much as 30 degrees!
If you are still on the fence using your 1k light because of the electricty etc, I would spend some extra money and spring for a 600 watt with a vented hood.
This is a great investment, will be very good for your space, and when you do finally move into a larger space, the light is still very useful. Then you can simply add your 1000 watt light to your grow later should you chose to expand.
Or, maybe trade/sell your 1000w light for a 600 watt light. They run cooler and are more efficient and should eliminate the problems you have with electricity.
A 1k watt light draws about 7 amps. The average house circuit is good to 15 amps. It's not hard to over do it and start blowing things once you get everything plugged in.
As long as your not baking your plants, scotching leaves, and are keeping your room under 80 degrees, you fine.
Vented hoods are a godsend! Totally worth the money.
IMO sell the 1k, or better yet save it for later, get yourself a nice 600 with a vented hood and go to town.
You will be way happier using a 600 or 1000 over a 400, that's for sure.