Comparing Shower Types for Different Bathroom Layouts

Choosing a new shower is rarely just about the shape of the head or the finish on the valve. The deciding factor is almost always what your plumbing can deliver. Get that wrong and you can spend £600 on a rainfall head that dribbles, or fit a thermostatic bar valve to a gravity system and wonder why the temperature swings every time someone flushes a loo. Before you compare models, find out what you have and what you can realistically achieve.

Start with Pressure and Flow Rate

Two numbers matter: pressure, measured in bar, and flow rate, measured in litres per minute. Pressure tells you whether a shower will work at all; flow rate tells you how good it will feel. A shower that delivers 12 litres per minute feels generous, one at 6 litres per minute feels functional, and anything under 5 litres per minute feels like a punishment.

To test your flow rate, run the cold tap in the bathroom into a jug or bucket for 30 seconds and measure what you collect. Doubling that figure gives your litres per minute. Do the same on the hot tap and compare — if hot is much slower, a mixer shower will struggle.

• Gravity-fed systems (cold tank in the loft, hot cylinder) usually give 1–3 bar at the bathroom, often less. Flow depends on how far the tank sits above the shower head.
• Combi boilers give mains pressure but limited flow, typically 10–14 litres per minute, and that drops if a tap or appliance runs at the same time.
• Unvented cylinders offer mains pressure with strong flow, often the best setup for a high-performance shower.
• Mains cold with no stored hot water limits you largely to an electric shower.

Electric Showers: Simple and Self-Contained

An electric shower heats cold mains water as it passes through, so it needs only a cold supply and its own dedicated circuit. A 9.5kW unit draws roughly 40 amps, so check your consumer unit has a spare way and that the cable is the correct size — retrofitting a 10.5kW shower onto old 6mm² cable is a job for a qualified electrician.

They suit en-suites, loft conversions, small flats and anywhere without stored hot water. The trade-off is flow rate. In winter, when incoming water is colder, an 8.5kW shower may only manage 4–5 litres per minute. That is fine for a quick wash, but it will never power a large drenching head. Where two bathrooms are in use at once, an electric shower in the second one is often the pragmatic answer.

Mixer Showers: Ideal for Combi Boilers and Unvented Cylinders

A mixer valve blends hot and cold supplies and relies on your existing hot water. That makes it the natural choice where you have a combi boiler or unvented cylinder, and where both supplies arrive at similar pressure. You get the full flow of your system, so a proper rainfall head becomes realistic.

The weakness is pressure balance. In a gravity-fed home, hot and cold can arrive at different pressures, causing the temperature to drift as the cold tank empties or a tap is opened elsewhere. Exposed bar valves are easy to fit and service; concealed valves look smarter but need access for maintenance, so plan a hatch or an accessible panel during the renovation.

Thermostatic Showers: The Family Bathroom Default

Thermostatic mixers hold the outlet temperature to within about a degree, even when someone runs a tap downstairs. For households with young children, older relatives, or anyone who dislikes a cold shock mid-shampoo, they are worth the extra cost. Some models carry TMV2 or TMV3 approval, which matters in care settings and rented properties.

They still need separate hot and cold feeds at reasonably balanced pressures, so they are not a solution for cold-mains-only installations. Low-pressure gravity versions do exist and work well with a pump, but a pump adds noise — site it away from bedrooms, and ideally on a solid floor.

Matching the Shower to the Room Layout

• Small en-suite: a 760mm or 800mm tray with a compact electric or thermostatic mixer suits tight spaces. Consider a folding or pivot door rather than a bulky enclosure.
• Shower over bath: a mixer on a riser rail works well, but keep the fixed head modest unless flow exceeds 10 litres per minute. A bath screen with a proper seal prevents constant mopping.
• Walk-in with a low tray: 900 x 900mm is the practical minimum for comfort, and 1200 x 800mm gives real elbow room. Check waste pipe fall before committing to the tray position.
• Wet room: requires full tanking and a linear or centre waste with adequate fall. Choose a thermostatic valve to reduce scald risk on a floor-level shower.
• Gravity-fed homes: either fit a pump or select a shower explicitly rated for low pressure. Do not guess.

Maintenance to Plan for Now

Showers reward a little forethought. Fit isolation valves on both supplies so future work is simple. In hard water areas, choose a head with silicone nozzles and descale it every few months — limescale kills flow rate long before a valve wears out. Electric showers have an inlet filter that should be cleaned annually, and they dislike scale intensely, so a water softener or inline scale inhibitor is money well spent.

Thermostatic cartridges are replaceable rather than a whole-valve job, so keep the model details. A dripping shower is usually a tired cartridge or seal, not a reason to rip the room apart. Finally, run the extractor fan during and after every shower and leave the door ajar — condensation, not limescale, is what ruins bathroom paint, grout and the plaster behind it.