145W - That sounds expensive to run 24/7. I'm looking to do this at some point in the future, and so did quite a bit of research...
After reading numerous threads, for what seemed like hours on end, the recommendation was to see if you could get a HP EliteDesk G2 800 i5 6500 on ebay for around £300, and use that as your base build.
Keep us informed, I'd like to know how you get on.