Very few houses have hydronic (hot water radiator) heating in North America; most have forced air systems with ductwork that does double duty as heating and air conditioning, supplying air to the wrong place at least half of the year. Almost everyone in Europe and those of us in older houses have radiators; it is quieter, there are no bulkheads for ductwork, and there is less dust moving around. But a big problem is the inertia, or thermal lag; it takes a long time for the temperature to change when you move the thermostat or the sun comes streaming through your windows. The Belgian radiator company Jaga seems to have solved this problem.
They have developed a new kind of radiator fin that holds a lot less water, combined with a lot more surface area, so that the thermal inertia is reduced and the reaction time is much faster. They claim that it would reduce CO2 output from the furnace by 220 lbs per year. They can also be combined with a radiant floor system to deal with their problem of thermal lag:
Low-H2O radiators react very fast and can be easily controlled. By contrast, radiant heating reacts slowly. For ultimate heating comfort, radiant heating should be combined with Low-H2O radiators. Furthermore, Low-H2O radiators make your system much more energy efficient. Use your radiant floor heating system to maintain your minimum temperature of 64°F. The Low-H2O element will bring your room to a comfortable 68°F when necessary, fast and with minimal energy consumption. This combination allows you to benefit from free energy such as the sun.
Not only are Jaga radiators efficient, they are gorgeous, and the Jaga booth was by far the most beautiful at the CMX-CIPHEX HVAC show in Toronto. The walls of the booth are covered with wood scraps left over from the manufacturing of wood radiator covers, as are the stools the salespeople sit on. You don't go to an HVAC show to see beautiful things, so it was a joy to see Jaga.