The 38 °C stop is a detent, not a safety device
A thermostatic mixer holds an outlet temperature while the supply moves under it — someone flushing a toilet, a washing machine drawing cold. Two things are worth being precise about. First, the 38 °C stop is a detent: a mechanical click you can deliberately push past, not a lock and not a scald-prevention device. It is described that way by the makers, and this site describes it that way too; always follow the manufacturer's instructions, and never treat a mixer as a substitute for supervision. Second, thermostatic cartridges need pressure to work, and makers state a minimum — commonly 0.5 to 1 bar. Below it the valve does not fail safely, it simply regulates badly. The rest is fitting: centre distance, almost always 150 mm on a bar mixer, and how many outlets the diverter feeds. We compare centre distance, stated minimum operating pressure, temperature stop, cartridge type, number of outlets, and finish.
Shower thermostat · 150 mm centres stated · 20–50 °C output range · 38 °C detent · G1/2 in and out · solid brass
The cheapest thermostat in this hub, and the one that publishes the most: a centre distance, an inlet and outlet size, a detent temperature and the whole range it will deliver.
Best for: A standard 150 mm wall installation on mains pressure, where the price matters and the figures still have to be there.
≈ 34 €
Shower thermostat · TurboStat cartridge · 38 °C detent · EcoJoy flow limiting with a release button · S-connections and metal rosettes
A thermostat built around a flow-limiting button you press to release full flow — and a water-saving claim published as a percentage with nothing behind it.
Best for: A household that wants a lower default flow without having to think about it, on a known standard wall installation.
≈ £105 / 96 €
Shower thermostat · 150 mm centres stated · 38 °C detent, lockable · plastic handle stated · takes any standard hose
A surface-mounted thermostat with a lockable 38 °C button and a plastic handle the maker defends on purpose — because limescale seizes metal ones.
Best for: A household where the temperature setting should stay put — the same shower, the same setting, every day.
≈ £40 / 50 €
Shower thermostat · solid brass stated · 38 °C detent · ½ in hose connection, no adapter · 2 rosettes and 2 S-connections
A solid brass thermostat that arrives with its rosettes, its S-connections and its fixings, from a German maker who answers the phone.
Best for: Replacing a shower mixer on existing wall connections, where everything should arrive in one parcel and the maker should be reachable.
≈ £65 / 61 €
Shower thermostat · 150 mm ±12 centres · G1/2 DN15 · SafetyStop 40 °C · EcoStop 10 l/min first position · silencer fitted
A thermostat that publishes its centre distance with a tolerance, its limited flow in litres per minute, and a built-in silencer — three things nothing else on this page states.
Best for: An existing wall installation whose centres are close to but not exactly 150 mm, in a bathroom where shower noise carries.
≈ £138 / 111 €
