Thermostatic Valves

The easy solution for energy saving

What's a valve?

The valve is a simple tap that regulates the flow of hot water in and out of the radiator and changes the temperature of the room only when opened or closed manually.

There are three types of valves: non-thermostatic, thermostatic and thermostatic

The combination of a thermostatic head and a thermostatic head, is the best system to obtain a correct regulation that allows you to decide independently the temperature control of each domestic environment.

In a radiator there are two types of taps... the valve for the water inlet and the lockshield for the outlet.
The thermostatic head, if any, must be mounted only on the valve body from where the hot water will enter the system.

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What's a thermostatic head?

The thermostatic head is a device, which installed on radiators, allows to regulate the flow of hot water. In fact, depending on the temperature you want to reach in a given environment, the head will increase or decrease the flow of hot water to the radiator. The main element of the thermostatic head is the control "motor" containing a specific thermostatic liquid. If the temperature in the room is higher than the preset one (e.g. 20° C), the probe connected to the control "motor" causes the thermostatic liquid to increase in volume causing the actuator (cylindrical body similar to a plug) to move, which in turn reduces the hot water passage section (and therefore the flow rate), allowing the remaining water to be conveyed to the other radiators. If the ambient temperature is lower than the set temperature, the reverse process occurs.

The advantages of thermostatic heads

The thermostatic heads allow to reduce waste and improve comfort by stabilizing the temperature at different values in the various rooms according to the needs.

Thermostatic valves are required by law in all apartments with central heating. Specifically, thermostatic valves must be installed on each individual radiator.



This is a very smart solution because it not only allows to improve the management of consumption, but also to measure the actual consumption that is made by each tenant of the condominium, defining a proportionality between actual consumption and the amount to be paid optimizing the costs related to heating and consequently a significant saving on the gas bill.

This technology gives access to the building recovery/renovation tax relief program.


Rules for correct use of thermostatic heads

Keep the thermostatic head as free as possible (the room temperature sensor must be able to detect the temperature inside the room)

Eliminate anything that prevents normal air circulation near the radiator (curtains, furniture, radiator covers, shelves).

Remove any heat sources (such as ovens or stoves).

Close the valve when changing the air in the rooms (keeping windows and heaters open at the same time wastes a lot of heat).

Close the shutters in the evening so as not to dissipate the heat unnecessarily.

Leave the head on 5 during the summer period, so as to avoid the formation of limescale and the consequent blockage of the head.

Leave the valve on 1/2 in rooms that are not in use or if you leave the accommodation empty for a few days.


How to distinguish a normal valve from a thermostatic valve?

Most thermostatic radiator valves have numbers, graphics or other control buttons, manual valves usually have no numbers or buttons.

There may be signs such as plus and minus (or on/off) indicating the direction in which you need to turn it to open or close it.

To understand if a valve is manual or thermostatic, simply unscrew the valve knob, if it has a piston that can be pushed in, then you can be sure that the valve is thermostatic. Replacing the valve control knob with a thermostatic head will allow you to better adjust the room temperature in order to ensure better comfort, energy saving and CO2 emissions.
Transforming the manual valve with a thermostatic head is very simple. (video)

If the manual valve does not have any piston inside it, it is necessary to contact a hydraulic professional to replace the valve body.


Conditions to check.


The thermostatic heads can be installed on all radiators (radiators), without special conditions except for the availability of the thermostatic valves on which the heads will be placed.
Most thermostatic valves have a universal connection M30 x 1.5 (Irsap valves have this type of connection); other valves need an adapter to connect the heads to the valve.

Irsap offers as accessories the adapters of the major valve manufacturers (FAR, Giacomini, Caleffi, Danfoss).


Certification of thermostatic heads

The white Irsap thermostatic head is certified.

To ensure optimum operating performance and to avoid unnecessary costs and degradation, certified thermostatic valves meet the following specifications (proven by the KEYMARK certification scheme):


Opening and closing characteristic curve

Flow rate at different pressure differences

The influence of water temperature

The closing speed

Temperature resistance

Mechanical fatigue test

Thermal fatigue tests




Irsap for the environment

Photovoltaic production
Actual Power
0,00 kW
Produced power
8.599.128,26 kWh
CO2 emission
3.491,25 t