Differences exist between rules of thumb and precise calculations.

 The following formula has been around the North American hydronics industry for a long time:  

 North American hydronic professionals can now choose from dozens of modulating/condensing (mod/con) boilers. Many are designed for wall-mounting. Those who design these boilers strive for small enclosures and low weight.  

An installer plans to use a geothermal heat pump to supply warm water to a multizone radiant ceiling panel system.  Having heard that radiant ceiling panels also can be used for cooling, he decides to pump chilled water through the same radiant ceiling distribution system.

 For decades, well-designed and -installed hydronic heating systems have earned a reputation for superior comfort. Still, potential customers who understand and desire the benefits of hydronic heating often ask, “But how does this system provide cooling?”  

A low-mass copper tube boiler is installed with six zone circuits controlled by zone valves. The installer got a great price on a “contractor pack” of 3/4-in. copper tees, so the supply and return headers are build with 3/4-in copper, as are all the zone circuits.

Interest in biomass heating systems continues to rise, especially in rural areas of the United States and Canada. Although plenty of devices are available that burn wood to heat water, the state-of-the-art device is a wood-gasification boiler.

A group of masons pour a 6-in.-thick concrete slab containing 5/8-in. PEX tubing at 12-in. spacing. A nearly complete layer of extruded polystyrene insulation is under the slab. But what are they doing wrong?