Steam Shower Water Pressure: Will One Work in Your Home?
Share
Most questions about steam showers are about size and price. The one that actually decides whether a cabin will work in your home is water pressure. Our steam showers and shower cabins need at least 2.5 bar, and no more than 3.4 bar, on both the hot and the cold feed. Plenty of UK homes fall outside that range, and it is far better to find out before you order than after the cabin is built.
The good news is that it takes ten minutes to check, and there is a straightforward fix either way.
Why a shower cabin needs more pressure than an ordinary shower
A normal mixer shower feeds one outlet. A cabin feeds a monsoon overhead shower, a hand shower and six body jets through a thermostatic valve, and the body jets in particular need pressure behind them to feel like a massage instead of a trickle. Below 2.5 bar the cabin still runs, but the jets are weak and the thermostatic valve can struggle to hold a steady temperature. The steam generator is less affected, since it only needs to fill a small tank.
What pressure does your system give you?
How to measure it in ten minutes
Buy a water pressure gauge with a tap adaptor. They cost around ten pounds from any plumbing merchant. Screw it onto the tap nearest the bathroom, make sure no other water is running in the house, open the tap fully and read the dial. Test at the time of day you normally shower, because mains pressure drops at peak times. If your hot water is gravity fed, the cold kitchen tap will not tell you what the bathroom hot feed is getting, so ask your plumber to test both feeds at the bathroom.
If your pressure is too low
Gravity fed system: fit a twin impeller shower pump, which boosts the hot and cold feeds together so they stay balanced. A pump rated between 2.0 and 3.0 bar is the usual choice. Your plumber will check that the loft tank is large enough to keep up with it.
Mains fed system with poor pressure: you cannot fit an ordinary shower pump directly to the mains. The usual answers are a mains booster set with a break tank or an accumulator. Speak to your plumber, and it is worth asking your water company to check the supply first, since the fault is sometimes on their side.
If your pressure is too high
Some homes, especially at the bottom of a hill or near a pumping station, see 5 bar or more. Above 3.4 bar you risk damaging the valves and hoses in the cabin. The fix is a pressure reducing valve on the supply to the bathroom, set to 3 bar. It is a small, inexpensive fitting.
Balanced hot and cold matters too
A thermostatic valve works best when hot and cold arrive at similar pressure. Mains cold with gravity hot is the classic mismatch, and it causes temperature swings in any shower. If that is your setup, a pump or a move to an unvented cylinder solves both problems at once.
Quick answers
What water pressure does a steam shower need?
Between 2.5 and 3.4 bar on both hot and cold.
Can I have a steam shower with a gravity fed system?
Yes, with a twin impeller shower pump fitted to boost both feeds.
Will a steam shower work with a combi boiler?
Usually yes, as long as your mains pressure reaches 2.5 bar and the boiler has a reasonable flow rate. Measure the pressure first.
What if my mains pressure is over 3.4 bar?
Fit a pressure reducing valve on the bathroom supply, set to 3 bar.
Next step
Once you know your pressure is in range, the rest is choosing a size. The steam shower size guide and finder filters every model by shape, or you can browse all steam showers and shower cabins. If you would like us to talk it through with your plumber, call 0330 133 6617.
This guide is general advice. Always have pressure confirmed and any pump or valve fitted by a qualified plumber.