How to choose a shower mixer tap
Three questions are all it takes: concealed or exposed, thermostatic or manual, and the pipe center distance of your water inlets. The first two depend on your installation and usage, while the third is determined by your existing plumbing.
Start with the center-to-center distance; it is the only point where you have no margin for error when renovating.
Standard center-to-center distance in France : 150 mm between the axes of the two inlets.
Tolerance of adjustable eccentrics : approx. 145 to 160 mm.
Installation height : 110 cm from the finished floor, center line.
Partition depth for recessed installation : 80 mm minimum behind the plate.
An imported mixer tap designed for 100 or 120 mm is available, and it cannot be mounted on a French installation without specific offset connectors. Measure before ordering, the process takes thirty seconds.
Recessed, wall, or ceiling
The installation method is not an aesthetic choice, it is a construction site decision, and it is determined at the moment the wall is opened.
| Pose |
What it gives |
What she is asking for |
| Recessed |
Bare wall, only the plate is visible, no corners for limescale to build up, real space saver |
Open bulkhead, watertightness, access hatch |
| Surface-mounted wall light |
Visible, reversible, and repairable body without breaking |
Thirty minutes on existing arrivals |
| Ceiling |
Ceiling-drop power supply, wall control |
Opening scheduled for structural works |
Concealed installation is the ideal choice for complete renovations and new builds. The rough-in body is installed during the construction phase, while the trim kit is selected separately, allowing you to change the style later on without touching the plumbing. The classic mistake is not planning for an access hatch : the body contains the cartridge or the cell, which are wear parts that need to be replaced. Without access, the only solution on the day of a breakdown is to break the tiles.
Thermostatic or manual, what really changes
A manual mixer tap blends hot and cold water depending on the position of the lever. A thermostatic mixer features a cartridge that automatically adjusts the mix to maintain the requested temperature, regardless of any pressure fluctuations in the system.
| Criterion |
Mechanics |
Thermostatic |
| Temperature stability |
Variable, sensitive to drafts elsewhere |
Stable to the nearest degree |
| Anti-scald protection |
None |
38 °C safety stop, manual override |
| Setting time |
A few seconds with every shower |
Immediate, the instruction is memorized |
| Flow rate and consumption |
Water lost during adjustment |
Reduced, no guesswork |
| Care |
A ceramic cartridge |
Limescale-sensitive cell |
A thermostatic mixer is justified in three cases: a household with children or elderly people, a home where water pressure fluctuates, or a system with an instantaneous water heater. In a studio apartment with a hot water tank and a single occupant, a manual mixer does the job for half the price.
An honest look at thermostatic valves
The cell scales up. In water above 30 French degrees, it requires annual descaling and eventually needs to be replaced after seven to ten years. The mechanical version only has its cartridge, which is simpler and cheaper. The anti-scald safety feature remains crucial with children, but it comes with a long-term cost.
Outlets, diverter, and hose
A single-lever mixer feeds a single outlet. As soon as you want a shower head and a hand shower, you need a diverter, either integrated into the body or wall-mounted.
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An outing : douchette sur flexible, la configuration la plus courante et la moins chère.
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Two outlets : overhead shower and hand shower, controlled by a two-way diverter.
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Trois sorties : adding side jets or a bidet spray to a complete concealed kit.
Each additional outlet divides the available pressure. Allow for at least 2 bars of pressure at the tap connection to comfortably supply two outlets. Below this, the overhead shower head will lose pressure as soon as a second function is turned on.
As for the hose, the stainless steel braided type holds up better than sheathed PVC and can be replaced for just a few euros. Check for a non-return valve, which is mandatory to prevent back-siphoning into the mains, and an anti-twist system at the connection.
Installation and connection
Installing an exposed wall-mounted mixer tap takes just four steps, provided that the S-unions are fitted correctly.
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Turn off the water and remove the old mixer tap. Clean the thread of the wall outlets.
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Screw in the cam locks with Teflon or plumbing hemp, positioned to achieve the exact center-to-center distance. Always finish by tightening, never by unscrewing to adjust.
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Check the plumb and center-to-center distance level before installing the rosettes.
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Assemble the body with its gaskets, hand-tighten, then turn a quarter-turn with a flat wrench protected by a cloth.
Hot water on the left, cold water on the right. A mixer tap installed backwards will work but will deliver the opposite of the temperature markings, and on a thermostatic mixer, the safety stop will become inoperable.
For flush mounting, the body is installed in the partition wall flush with the finished surface, the pressure test is carried out before closing up, and then the tiling is laid. The plate is mounted last.
Frequently asked questions
How to choose a shower mixer?
First measure the center-to-center distance of your inlets, 150 mm being the French standard. Then choose between thermostatic and manual depending on the presence of children and the stability of your water pressure. Whether you choose a concealed or exposed installation depends on your project, not the product.
What are the advantages of a thermostatic mixer tap?
The temperature remains stable even if another tap is turned on, and the 38 °C safety stop prevents accidental scalding. It also reduces water wasted during adjustment. On the downside, its cartridge can scale up and requires annual descaling in hard water areas.
What is the standard center-to-center distance for a shower mixer?
150 mm between the centers of the two inlets, in France. The included adjustable offset connectors accommodate a tolerance of approximately 145 to 160 mm. Beyond this, specific offset connectors or relocating the inlets will be required.
What are the types of shower mixers?
Four families: concealed mechanical, concealed thermostatic, exposed wall-mounted, and ceiling-mounted. These are complemented by complete concealed kits that include the mixer, shower head, and hand shower, controlled by a two- or three-way diverter.
How to install a shower mixer tap?
Turn off the water, remove the old mixer tap, screw in the S-union connectors using Teflon tape while adjusting the center-to-center distance, check that it is level, then mount the mixer body with its washers. Tighten by hand, then add a quarter turn with a wrench, using a cloth to protect the finish.
At what height should a shower mixer be installed?
110 cm from the finished floor, measured to the center of the unit. This height is suitable for the majority of users. In a shower designed for a seated person, lower it to 90 cm so that the control remains within reach.
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