I'm working on a tracking document to project the replacement of the HVAC equipment on state owned buildings. Boilers and chillers aside, what is considered the age to change out a system? Keep in mind that the up keep on these appliances has been shaky at best before I arrived. The R22 to 410 factor is going to play a factor now more than in years past as will SEER. Currently I'm working with split systems and RTUs ranging from 1990-2008 model years.

I'm also interested in maybe changing out some units for Daikin splits, but I'm hearing that the average tech wouldn't be able to work on them without factory specific training.