What Owners Need to Know About ... Rooftop Units: Repair or Replace?

Heating/Piping/Air Conditioning Engineering, Feb. 2014, by David Negrey. (Free registration required to view full article.)
http://hpac.com/air-conditioning/what-owners-need-know-about-rooftop-units-repair-or-replace

"Most light-commercial HVAC products are designed for a useful life of 15 to 20 years. During that time, however, the reliability and cost-effectiveness of operation often is dictated by factors beyond the manufacturer’s control. At the same time, newer, more efficient HVAC products often can reduce maintenance and utility costs. When it comes to deciding whether to repair or replace an older rooftop unit, it is important to consider a number of factors, including current condition, age, efficiency, maintenance/repair history, and associated utility costs. This article will discuss the process of making an informed decision."