So I think I want to get a video projector to rear project something out of my front window for halloween.
I decided I need something more powerful then the torpedo or zoombox.

so now I need some help figureing out the difference in home theater projectors and office type projectors.
I thought the more lumins the better. but I was looking at home theater units with HDmI inputs with only 1100-1200 lumins 160" display $2500. and very high comntrast ratio
while office projectores had 2000 lumins but only composite video input with up to 300" display for around $1000

one question I had that the guy at circuit city couldnt answer is:
can they both do rear projection?

I originally thought I would buy as cheap as I can and only use it for Halloween projection. but that is still pricey for just a halloween display.
so I started upgrading features I would want to use it as a theater system... then it started getting really expensive.

any advice ???