I have been using a base model 2014 Mac Mini for a bit more than a week, and I haven't had any issues with either heat or noise. I do, however, only use it for web browsing. I was lucky enough to get it for $349 with a special deal from Best Buy for students, so whichever model you can get cheaper should be fine.I would like to purchase either a 2012 or 2014 base model Mac Mini.
Because it will be in a confined space, the less heat generation the better. I am assuming 2014 1.6ghz would be best in this situation.. Would that be correct?
Dark Void said it best! Although the newer minis are more efficient, heat production is largely a result of the workload. An idling 2012 or older machine will use much less energy than a new mini that is running a typical Handbrake job.
What do you plan to do with the machine? That is a versatile computer. Are you planning to limit your options because of environmental factors?. For my systems, I prefer to provide adequate cooling wherever the computer is mounted.