Hydronic radiator heating with thermostatic valves: Improves thermal comfort or upgrades efficiency?

Energy performance standardisation evaluates all measures at the building and building services level that improve energy efficiency. Thermostatic valves are one of the choices, which are considered. To demonstrate their effect, a detached house, a terraced house and an apartment with three different levels of thermal insulation and hydronic heating were evaluated. Variants considered were (1) the fuel, (2) the boiler and (4) thermostatic valves or not. The TRNSYS and BOILSIM tools were used to simulate an Ukkel TRY-year. That way, comfort, system efficiencies, annual energy consumption, annual CO2 release and net present value were evaluated. The results learned that thermostatic valves not always decrease consumption. In fact, in the moderately insulated detached and terraced house the valves improved comfort, not energy efficiency. In the well-insulated detached and terraced house and in the apartment instead, a net decrease in heating was noticed, together with a better comfort.