This invention relates to valves (2) for heat exchanger thermostats (1), thermostat heads (3) for a heat exchanger thermostat (1) and a heat exchanger thermostat (1) comprising a valve (2) and a thermostat head (3). According to the invention, temperature sensitive means (10) are provided on or within said valve (2) and/or said thermostat head (3) influencing a throttling behavior of said valve (2) depending on a temperature of a fluid controlled by said valve (2). By this, a premature throttling of the fluid controlled by said valve (2) due to heat transfer between the fluid and the thermostat head (3) may be prevented. Thus, a good ambient temperature may be established which comes closer to the desired room temperature.