can often be programmed or remote-controlled so that individual radiators in a house can be programmed for different temperatures at different times of the day. Such increased control allows more advanced controls, which can result in even better energy and CO savings. Some other possibilites with such systems is that the temperature sensor can be placed away from the radiator in another place in the room, which may result in a more relevant temperature reading in the room which can be used to set the TRVs operating point. Some electronically controlled valves run on batteries which must be changed at regular intervals, while others can be connected to the power grid. Electronically controlled variants may also require additional setup, for example by connecting to a mobile phone application through a smart home hub using wireless protocols such as Zigbee or Z-Wave Some of the more well known manufacturers of smart TRVS include Wiser by Drayton Controls, Tado, Hive and Bosch. Temperature scales Instead of marking the adjustment knobs with temperature in the Celsius scale, many manufacturers have a tradition of using their own scales, for example 1-5. Why manufacturers have chosen not to use actual temperature scales is not clear. The table below gives some examples of conversion from proprietary scales to the Celsius scale. Physical connection standards There are several different standards for the screw connection between the TRVs adjustment wheel and the thermostat on the radiator. Some common examples are: M28x1.5 valve (27.5 mm) - Used by MMA, Herz, Orkli, COMAP, T+A, and others Caleffi valve Danfoss: Several variants, for example K valve (M30x1.5), RA valve (23 mm), RAV valve (34 mm), RAVL valve (26 mm) or the RTD valve Giacomini valve See also Thermostatic mixing valve Wax thermostatic element Thermostat Notes and references Residential heating Plumbing Temperature control it:Termostato