If you can work out a way of securing the window so you can vent heat outdoors, do the HPS.

CFLs do run cooler, but they certainly produce heat. You'll have to vent heat from them anyway.

If you do run CFLs, you trade off bud density and total yield. It's the high light intensity from HPS that makes the weight. CFLs are great for seedlings/clones, OK for slowly vegging mother plants but really a last resort in flowering.

If there's no way you're going to keep the temps below 80F/26.5C without CFLs, they can be the difference between growing a little or none at all.