Originally Posted by derickmc
This is probably a stupid question but I have been advised to install thermostatic radiator valves to improve the energy efficiency of my house.
Are TRV's just regular valves i.e. with a random scale of 1 to 5 on them or are they something much more advanced i.e. like a cylinder stat where you can set an exact temperature to be heated to ?
TRVs are supplied in two basic components:
1. a valve that replaces the existing valve. Your original valve is twist to close (3 or 4 full turns typically). The TRV valve is spring loaded, and the spring opens the valve (this is important to know if you ever want to manually close the valve).
2. a thermostatic head that contains a wax that expands/contracts with varying temperature (same principle as the thermostat in your car). As the wax heats up it expands and pushes the spring loaded valve closed, as it cools it contracts and allows the spring to open the valve.
I have them in my upstairs bedrooms as the literature supplied recommends a set temp. of 18 degrees (this is 2 on the 1-5 scale). So the number 1-5 corresponds to a set temp.
They recommend that the TRV head is as far from the radiator as possible (so that it senses the average room temp rather than the air immediately beside the radiator). So mine are installed horizontally (you can fit them either way). You can also fit them on the inlet or the outlet of the radiators, so mine are on the side closest to the middle of the room (avoid putting them behind furniture if possible, for the same reason).
If you were thinking of putting a TRV on every
radiator in the house then you'd have to install an automatic bypass valve (in case they all close automatically together). My new condesning boiler has this bypass valve fitted internally.
My TRVs cost less than €20 euros each, well worth it I reckon.