How to Choose a Shower
Work out which type of shower suits your home's water system, pressure and household needs, from electric to digital showers.
The right shower depends less on style than on the water system behind the wall. This guide explains how electric, mixer, thermostatic, digital and power showers differ, and how pressure and system type decide which will actually perform.
Start with your water system, not the shower
The single biggest factor in choosing a shower is the type of hot water system in the property, because it determines both the water pressure available and which shower types will actually work well. Fitting the wrong type against your system is the most common cause of disappointing water pressure at the shower head.
- Combi boiler — hot water heated on demand, pressure follows the incoming mains supply
- Unvented cylinder (mains pressure) — stored hot water at mains pressure, generally good for mixer showers
- Vented (gravity-fed) cylinder with a header tank — pressure depends on the height of the tank above the shower, often low
The main shower types
Electric showers heat cold mains water directly as it passes through, so they are largely independent of your hot water system and only need a cold feed and a dedicated electrical supply. Mixer showers blend hot and cold water from your existing supply, so their performance depends entirely on the pressure and flow your system provides. Thermostatic mixer showers add a valve that holds the output temperature steady even if pressure elsewhere in the house changes, for example when a tap is run or a toilet is flushed. Digital showers use an electronic control unit, often with a separate processor, to give precise, repeatable temperature and flow settings, usually with a remote or wall-mounted control. Power showers combine a mixer valve with a built-in pump, designed for homes with low incoming pressure that still want mixer-shower blending of temperature.
Shower types compared
| Type | Best suited to | Key consideration |
|---|---|---|
| Electric shower | Any system, especially low-pressure gravity-fed homes | Rated in kW; higher kW gives a warmer flow at higher flow rates |
| Mixer shower | Combi or unvented mains-pressure systems | Needs good, balanced hot and cold pressure to perform well |
| Thermostatic mixer | Any system with adequate pressure | Protects against scalding from pressure fluctuations elsewhere in the house |
| Digital shower | Combi, unvented or pumped gravity-fed systems | Needs mains electricity for the control unit; precise, repeatable settings |
| Power shower | Low-pressure gravity-fed systems wanting mixer-style control | Built-in pump; check tank and pipework can supply the required flow |
Water pressure, pumps and kW ratings
Mixer and digital showers on a gravity-fed system usually need a shower pump to give a satisfying flow rate, particularly if the header tank sits close to ceiling height above the shower. Pumps are rated by their boost factor (for example 1.5, 2.0 or 3.0 bar) and by whether they suit a positive head (tank above the pump) or negative head (tank below or level with the pump) installation — the two are not interchangeable, so check the pump specification matches your plumbing arrangement.
Electric showers are rated by their power in kilowatts, typically from around 7.5kW up to 10.5kW or higher. A higher kW rating heats the water more as it passes through, which matters most in winter when incoming mains water is coldest, but it also requires a heavier electrical supply cable and consumer unit capacity, so the correct rating should be confirmed against the household's existing electrics before purchase.
- Larger households or those wanting simultaneous hot water use generally benefit from higher flow rates and larger cylinders, not just a bigger shower
- Low incoming mains pressure limits electric shower performance regardless of kW rating
- A plumber or electrician can confirm whether your existing pipework and electrical supply can support your preferred shower
Enclosure and tray considerations
The shower unit is only part of the job — the enclosure and tray need to suit the available space and the type of shower fitted. Quadrant and offset quadrant enclosures make efficient use of a corner in a smaller room, rectangular enclosures suit a wider recess, and walk-in or wet room panels give an open feel but need careful attention to floor falls and waterproofing (tanking) to avoid water escaping the wet area.
- Match tray size to the enclosure and confirm the waste position works with existing pipework
- Low-profile trays sit closer to the floor for easier access but may need the floor build-up adjusted
- Wet room installations need a professionally formed fall to the drain and full tanking beneath the tiles
- Leave clear space for the door to open without hitting the WC or basin
Shop enclosures and trays
Matching the shower to your household
Think about how the shower will actually be used day to day. A busy family bathroom used by several people each morning benefits from a thermostatic mixer or digital shower that holds a consistent temperature when other outlets are used elsewhere in the house. A guest en-suite used occasionally may be well served by a straightforward electric shower that needs no boost from the hot water system at all.
Related reading
Frequently asked questions
- Can I fit a mixer shower with a combi boiler?
- Yes, a mixer shower generally works well on a combi boiler since hot water is heated on demand at mains pressure, though performance still depends on your incoming mains pressure and flow rate.
- What kW electric shower do I need?
- Common ratings run from around 7.5kW to 10.5kW or higher. Higher kW gives a warmer shower at higher flow rates, especially in winter, but needs a suitably rated electrical supply, so check this against your existing consumer unit and cabling.
- Do I need a pump for a mixer shower?
- Only if your water pressure is low, typically on a gravity-fed system with a header tank close to the shower height. Combi and unvented mains-pressure systems usually do not need a pump.
- What is the difference between a thermostatic and a standard mixer shower?
- A thermostatic mixer includes a valve that automatically maintains a set temperature even if pressure changes elsewhere in the house, reducing the risk of sudden temperature swings or scalding.
Shop the products in this guide
Plumb Supply Team
Practical buying information from the Plumb Supply team.
