Radiant & Hydronics

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What happens when a heating contractor spends three nights in one of America's most iconic historic hotels? Scott Secor shares observations on the Old Faithful Inn's hydronic heating system, from ornate cast-iron radiators to noisy TRVs and the questions they raised.

As utilities and building owners look for new energy storage solutions, hydronic thermal storage presents an efficient alternative to batteries in many applications.

The transition to automated production aims to deliver performance and installation benefits. 

Figure 1 shows a hydronic system that’s intended to supply four panel radiators, each with their own thermostatic radiator valve and an indirect water heater from a gas-fired sectional cast-iron boiler. The system is designed using primary/secondary piping. The primary circulator operates whenever the space heating load or the indirect water heater call for heat. 

The upward pricing trend that carried into the new year is continuing through February and into March, with a steady stream of plumbing, hydronic, HVAC and PVF manufacturers announcing increases. While many adjustments are landing in the low- to mid-single-digit range, several manufacturers are implementing category-specific or “various” increases, with select product lines moving higher.

AHR Expo 2026 made it clear that hybrid systems are no longer an emerging idea; they are the answer to the ongoing balancing act of meeting decarbonization goals while remaining realistic about the grid's capacity for electrification. Manufacturers emphasized systems that combine electric technologies, gas-fired equipment, and advanced controls.

In hydronic systems, the circuit usually passes through the boiler, which adds heat. When using a block heater and the boiler is off, it dissipates heat from the circuit. This heat loss must be considered when measuring the circuit's true "net" heating output.