Attic tent?

Have a huge attic that's wayyyy to ht to grow in from April through October.

During the winter months it can get pretty cold in there but would the hps bulb be able to keep the grow tent of proper temp or is any of this even possible?

Yes it is...but

A few of us have tents in the attic. Like you say, too hot during the summer but during the winter it should work fine as long as you don't live someplace ridiculously cold.

I bought a 15,000 btu air/heater / for up there ,works preety good, Temps range from 68-84 summer or winter

It can get down to 0 or -10 here but that's pretty rare, most nights are in the 20's in the winter.