Air Conditioning, Heating & Refrigeration News, Jan. 27, 2014, by Matt Bishop.
http://www.achrnews.com/articles/125637-boilers-water-heaters-efficiently-evolve

"When it comes to boilers and water heaters, manufacturers are sensing an ongoing trend — the move to higher-efficiency models." Article also discusses the trend towards space efficiency for residential models, and hybrid systems for commercial boilers.