Shower heads, and why a head cannot make pressure

A shower head is a cheap change that feels like a big one, and the shelf knows it. Twenty-one heads are on this page and every single title makes the same promise. It is worth understanding why that promise is not the head’s to make, because the honest version of it is on eight of the same titles under a different name.

Where pressure comes from

Water arrives at a shower at whatever pressure the system gives it. A combi boiler on the mains gives one to three bar. A hot water tank in an airing cupboard fed from a cold tank in the loft gives a tenth of that, which is why so many British showers are feeble and why the pump under the bath exists.

The head is at the end of that. It cannot add pressure. What it can do is push the water it gets through smaller holes, so the same litres come out as faster, sharper jets. On a combi that feels like a stronger shower, and it is a fair trade. On a gravity-fed tank system there is not enough flow to begin with, and narrowing the holes makes the dribble sharper rather than bigger. The handheld vacuum guide covers the same confusion from the other end: pressure and flow are two numbers, and the sellers only ever print the flattering one.

Eight titles say water saving, which is the same feature told honestly: fewer litres a minute through a head designed to make it feel like more.

The number nobody prints

Not one of twenty-one titles states a flow rate. A shower in this country runs at somewhere between eight and twelve litres a minute; a water-saving head takes that to six or seven. That figure decides whether a head is a shower or a mist, and the sellers have all left it out in favour of a word.

If you are on a combi, any of these will feel fine. If your shower is weak already, no head on this page fixes it, and the one with the most holes and the fewest words is the safest buy.

Twelve filters, and what is in them

Twelve titles say filter, filtered or purified. None says what the filter is.

There are two things it can be. A cotton pad or PP filter catches grit and rust from old pipes, and is worth having in an old building. A cartridge of mineral beads, calcium sulfite or a vitamin C block takes some chlorine out of the water for a few weeks, after which it is a decoration. One title here says vitamin C. One says fifteen stages, which is fifteen layers of the same two things.

What no filter in a shower head does is soften hard water. Softening is ion exchange in a cylinder the size of a fridge. A head that promises to do it in a tube the size of a thumb is promising the wrong thing, and the limescale on its own holes in three months will say so.

Two titles say protect skin or beauty. Read those as the vitamin C block, described by someone selling it.

One title says its filter element can be changed. That is the difference between a filter and a whole head you replace when it clogs, and it is on one title out of twelve.

Handheld or fixed, and the fitting

Eight titles say handheld, and a handheld screws onto the hose that is already on your wall. Five say rainfall, which is the wide fixed head that hangs from an arm, and that arm is not in any box here. Two say a hose is included and only one gives its length, 1.5 metres.

Every shower hose and head sold in Britain uses a half-inch BSP thread, and these almost certainly do too. No title says so. On the one page here where a head comes with a cleaning spray gun and another with a massage brush, that is the one line that would have been useful.

Modes, buttons and gimmicks

Thirteen titles give a number of modes, three to nine. Three is rain, jet and both, and it is all anyone uses; the rest are the same water through a different pattern of holes, chosen once and never again.

Two titles have a stop button, which pauses the water at the head while you soap. On a shower with a thermostatic mixer it saves water. On one without, it saves the temperature too, because the taps stay where you left them, and that is worth more than any number of modes.

One head has an LED temperature display driven by a little turbine in the flow. It works, it needs the water running to show anything, and it tells you what your hand already knew. One is propeller driven and calls itself turbocharged, which is a fan spinning in the water for the pleasure of the word.

Two titles give a size, 15cm and 23cm. A 23cm head is a rain head and wants a combi. A 15cm handheld is on the big side and heavy in the hand.

What I would actually do

For most bathrooms, the Cobbe. A brand you can look up, a filter, four modes, and the only title that tells you a hose is in the box and how long it is.

If you want a filter for old pipes, look for a head whose filter element can be changed, and buy the spare at the same time. One title here says so.

If you want it to last, the stainless one. It is the only title on the page that states a material, and 304 is the grade that does not rust.

If your mixer has no thermostat, the one with the one-key stop. Press it, soap, press it again, same temperature. That is the whole feature and it is a good one.

Whichever you buy, read high pressure as smaller holes, ask for the litres per minute, and if your shower is weak today, spend the money on the pump instead.