Understanding Thermostatic Radiator Valves
A thermostatic radiator valve, or TRV, controls an individual radiator's temperature by responding to the room's air temperature, letting you heat rooms differently rather than uniformly..
A thermostatic radiator valve, or TRV, controls an individual radiator's temperature by responding to the room's air temperature, letting you heat rooms differently rather than uniformly.
How they actually work
A wax or liquid-filled element inside the valve expands as the room warms, gradually closing the valve to reduce flow to that radiator.
What the numbers mean
The numbered settings are not exact temperatures but relative positions; a mid setting suits most living rooms, while a lower setting suits bedrooms or spare rooms.
Where not to fit them
The room with your main thermostat shouldn't have a TRV, since the two would compete against each other rather than working together.
Questions we get asked
Why has my TRV stopped responding?
The pin inside can stick if left in one position for a long time, particularly over summer; opening and closing it fully a few times often frees it.
Can TRVs replace a smart heating system?
They work well alongside one, giving room-level control, but they don't provide scheduling or remote control on their own.
Do I need a TRV on every radiator in the house?
Every radiator except the one in the room with the main thermostat should generally have one, for proper room-by-room control.