What is the difference between a pressure-balanced mixer shower and a thermostatic mixer shower?

Mixer showers are supplied with hot and cold water and these supplies can vary in temperature and pressure.  A pressure-balanced mixer shower recognises and compensates for fluctuations in the incoming water pressure in order to maintain a showering temperature within +/- 2°C.

However, pressure-balanced mixer showers do not make allowances for fluctuations in the incoming water temperature and under such circumstances the water delivered through the shower will be prone to temperature variation.

Thermostatic mixer showers, recognise and compensate for fluctuations in both the incoming water pressure and the incoming water temperature, so if someone runs a tap or flushes a toilet, the shower will adjust to keep the shower temperature within +/- 1°C this is important if there are young children or elderly people in your home. We always recommend and supply thermostatic mixer showers