i have to downgrade

400w HID
T5 : 4bulb=216watts, 8bulb=432watts

you will never get the same yields from a T5 that you will from a comparable wattage HID (the exception being a 250w HID vs a 4bulb T5. yields are comparable because the light and penetration levels are similar). the 1400w space heater is the culprit, hands down. 1400w x how many hours per day? vs 400w 12hrs per day?? even my commercial warehouse, with 20K watts was less then $1200/month ... do the math and your scenario makes no sense for the room being the cause of the high bill.

For a relatively cheap investment you can buy a device that allows you to determine how much it costs to run a device per month, and annually just by plugging in your electricity's bills hourly rate. Kill-a-watt ez meter.
http://www.amazon.com/P3-International-P4460-Electricity-Monitor/dp/B000RGF29Q/ref=sr_1_2?s=electronics&ie=UTF8&qid=1332329945&sr=1-2

On average my 1000w costs me around $35 a month, and the 400w around $15 a month to run. Factor in all your other stuff your using too.....pumps, fans, etc and with your 400w you can't be pushing over 1000w I'd say. Which shouldn't be anymore than around $50 a month, depending on your local electricity rates.
Buy the meter, run it for a month, tell your friend exactly how much your light costs to run. Problem solved.

This is the bee's knees when it comes to an argument with the females: http://en.seedfinder.eu/growing/energy-costs-calculator/

It beat my wife's argument. It beat my friend's girlfriend's argument. It beat my dad's wife's argument. USE IT TO PROVE IT!

400w is the rating for one hour. So the math for an average month is simply: watts X hours per day x 30 / 1000

If you are talking about 18/6, then your average monthly kWh usage is 216 kWh. So if your cost is around $.10/kWh, we're talking $21.60 per month, less during flowering.

So now both of them have seen the light lol good to go and I think I have em convinced we need a smaller hps for an overflow flower closet...gonna be a good day tater

Yay, a rare instance where logic and truth prevail!