We’ve come a long way since the days of gravity-hot-water heating. The physics haven’t changed a bit, but the systems sure have. 

Although the market for gas-fired boilers continues to track toward those that can modulate and operate with sustained flue gas condensation, conventional boilers (e.g., those not designed to operate with sustained flue gas condensation) still represent a significant portion of the market. 

With a considerable volume of contradictory information in circulation regarding the application of different technologies for HVAC systems, this article seeks to explain some of the technical aspects of variable refrigerant flow (VRF) systems, and offer comparisons on the basis of cost and performance to more standard hydronic systems. 

We’re only human, and most humans like to put off things until they absolutely have to be done. 

Most buffer tanks used in hydronic systems are piped in a “4-pipe” configuration.

There have been numerous studies over the years touting all the benefits of hydronic heating systems, including improved comfort and energy efficiency. 

Some hydronic system designers cling to certain system piping configurations — even when existing projects using those configurations have produced problems.