If you own commercial or industrial property, you know that the stuff needed in your buildings to support human beings that work in them is bigger than the stuff used in homes. It can also be older. The term “legacy” is used to describe older HVAC equipment. It is a polite way of saying old. Sometimes older than dirt. There are industrial AC systems where each unit is as big as a Class A motorhome. Working in HVAC repair in NYC, I have seen a lot of old stuff in buildings still being used. The longevity of a system is attributable to its original quality and its maintenance. In New York we have hot summers and cold winters. We can get torrential rains and blizzards that dump feet of snow. It is humid in the summer and dry in the winter. That is a lot for any HVAC system to handle. I am surprised that they last as long as they do.
If your HVAC system in your house is not working right and has needed more than one or two repairs, you might save money in the long run by replacing it now. For industrial applications repair is usually the most economical answer. Fortunately, even legacy HVAC systems for industrial buildings have been built with the long term use and repair in mind. You can swap out a lot of old parts and put brand new replacements in that are also utilized in new systems. Standardization of some things makes this easy, especially if electrical as well as size requirements remain standard. This is why it is economical even to do a repair that costs thousands on an HVAC system because the alternative to replace could be a whole lot more. What you want to do, though, if you have a commercial building, is to have a reliable and highly trained HVAC team keep your stuff operating at peak efficiency.