This article explains the different options available to you when choosing a shower for your new bathroom installation.
Shower types

Bath / Shower mixer
This Is A Bath Mixer Tap Combined With A Hose And Shower Head

This is a bath mixer tap combined with a hose & shower head.

PRO

  • Cheap as no additional shower unit is involved
  • Cheap as there no associated additional plumbing costs e.g. recessing supply pipes into the wall

CON

  • Inconvenient temperature adjustment due to the low level
  • Arguably cheap looking
  • Hoses sometimes don’t reach high enough to deal with tall users
  • Can only be fitted over baths, not in shower enclosures

Manual shower mixer
Manual Shower Mixer Valve

Mixer showers are so called because they mix the hot and cold water supplies (in a valve) before it is available at the shower head. They rely on the user to adjust the shower temperature when fluctuations in water pressure cause temperature changes.

They are available as surface mounted bar mixers, or in the form of concealed valves (see thermostatic mixer showers below for examples – they look the same but function a bit differently.)

Some can be installed with exposed chrome pipes as opposed to recessed pipes, which makes retrofitting these showers easier in some applications.

PRO

  • Temperature and flow adjustment is easier as the controls are more accessible than bath fillers
  • Can be installed on mains fed or gravity fed systems, provided the pressure from the hot and the cold water come from a source operating at the same pressure – if not, a pressure balanced mixer valve can be installed.
  • Can be fitted with a pump on gravity fed systems to improve water flow

CON

  • Generally more expensive to fit as the supply pipes (hot + cold) have to be recessed into the wall
  • A mixer shower will not increase the flow of water in your system.
  • If your water flows from your taps at a poor rate, this is the rate it will feed the shower.
  • When other water is used in the house, the shower will be affected – this may lead to scalding
Verdict
Get a thermostatic mixer instead for safety &an uninterrupted showering experience.

Power shower
Power Shower For The Bathroom

This unit is similar to a thermostatic mixer shower in that it blends hot and cold feeds, but it does so with the addition of an integral pump – hence the need for a power source.

NB All electrical work in bathrooms needs to be carried out by a competent electrician, who can self-certify the work carried out through their trade body e.g. NICEIC.

PRO

  • Give a fantastic shower experience with loads of water pumped out

CON

  • Expensive shower units
  • Expensive fitting, as plumbing & electrics are required
  • Large flow rates empty cold water storage cisterns quickly so up-sizing may be required*
  • Uses lots of water due to large flow rate
  • Can only be fitted to gravity fed systems as they require a store of water to pump from.
  • Cannot be used in conjunction with a combi boiler.

* The cold water tank should be no less than 50 gallons if it supplies many outlets,
A 25 gallon cold tank is acceptable for the shower alone.

Electric shower
Electric Shower For The Bathroom

Not to be confused with power showers, these units act as instantaneous water heaters, heating up cold water as it passes through them, and because of this they require a minimum mains pressure of 1 bar, and a flow rate of 8 litres / minute.

They can be run off mains water (normally) or water from a cold water cistern (requires specialist model). They also need a power source, which will normally involve running a large 10mm cable directly from the fuse box (via an isolating switch or pull cord) to the shower unit.

NB All electrical work in bathrooms needs to be carried out by a competent electrician, who can self-certify the work carried out through their trade body e.g. NICEIC.

PRO

  • Temperature stabilisers ensure consistent water temperature.
  • Can be used with any domestic water system.
  • Unaffected by boiler breakdowns so a good 2nd bathroom option.

CON

  • Low flow rates compared to mixer showers & power showers.
  • Expensive fitting, as plumbing & electrics are required.
  • Units without phase shutdowns can scald the next shower user.
Verdict
Lower flow rates (especially with the lower Kw rated models) compared to other shower types can make washing shampoo from long hair a chore, so use an electric shower in a 2ndbathroom or en-suite as a compromise to give you a showering option should your boiler break down (as it will be unaffected).

Digital showers
Digital Shower For The Bathroom

Digital showers are essentially modern mixer showers that work by taking water from both the hot and cold pipes and mixing it in a digitally controlled processing unit to achieve the desired temperature. (This unit can be located away from the showering area).

This water is then fed to the shower outlet, be that body jet, hand shower, fixed head or spray head at a constant flow rate as selected by the user.
Digital showers can be un-pumped (for use with combi / high pressure systems) or pumped (for use with gravity fed systems)

PRO

  • Simple to use – Flow & temperature can be controlled by the push of a button.
  • Temperature preferences can be pre-set for different users.
  • Wireless controls allow showers to be turned on without leaning over baths etc.
  • Can sometimes be fitted quickly due to the remote siting of the processor box e.g. in loft.
  • Can sometimes be easily retrofitted as supply pipes are not hidden in the wall behind the shower.
  • Can be used with any type of domestic plumbing system.
  • Gravity fed compatible models come with a pump to increase flow rate (This is a good alternative to installing a shower pump.)
  • Eco settings can help to limit water consumption by reducing the flow rate.
  • Suitable for older people with arthritis who may have difficulty turning manual valves.

CON

  • Expensive units – expect to pay over £400 plus installation.
  • Cables are required (on non-wireless models) to link the control to the processor box.
  • Electrical installation is necessary.
  • Repairing faults will be beyond the remit of most trademsen due to the electrical circuitry involved so make sure you get a model with a long warranty period.
  • Wireless units can be affected by wireless interference.

NB All electrical work in bathrooms needs to be carried out by a competent electrician, who can self-certify the work carried out through their trade body e.g. NICEIC.

Verdict
Very expensive with limited tangible benefits and lots of electronic components to break!Can be a bit ‘plastic-y.’Can get much better value with an equivalently priced thermostatic valve in my opinion. Heard many reports of units being temperamental from plumbers I know.

Maybe a more economically viable option when compared to installing a shower and a separate pump.

I would choose an Aqualisa Quartz or Grohetherm Wireless if I could afford it.

Shower pumps

Shower Pumps For The Bathroom

Shower pumps can be used to increase the water flow to the shower (or whole house) in gravity fed systems (those with a vented hot water cylinder) to give a better showering experience.

They cannot be used with high pressure systems such as combi boilers or unvented cylinders.

When installing a pump it is important to note that you may also have to upgrade the size of your cold water tank in the loft as it will empty much quicker when the pump is being used. 50 gallons is adequate for one shower application.

They are normally sited in the airing cupboard next to the hot water cylinder.
A variety of types of pumps are available depending on the particular application.
Pumps are also rated in bar which is the measure of pressure. The higher the bar rating, the higher the pressure.

An electrical connection is needed and all electrical work in bathrooms needs to be carried out by a competent electrician, who can self-certify the work carried out through their trade body e.g. NICEIC.

Electrical connections

The electrical connections to an electric shower are covered by many regulations:
An electric shower must be installed on its own circuit and not spurred from any other connections or appliance.

If installing an electric shower where there was not one there before, an electrician will need to run a new supply from the fusebox to the bathroom – this may cause disruptions in the form of lifting floorboards and chasing cables into walls that will then need replastering & redecorating.

Check that your consumer unit is capable of providing the current necessary – must be rated above 60 amps.

An RCD (residual current device) must be installed as, either part of your existing consumer unit, or separately, interrupting the circuit to the shower. If you have a recently upgraded fusebox then you should be able to utilise this, otherwise it may be worth installing a new consumer unit.

Connection to the consumer unit should be by means of a MCB (miniature circuit breaker). Fuse, switch and cable ratings are also vital and a 10mm cable can be used for most installations. This makes upgrading your shower much easier in the future.
Different ratings of electric showers require minimum cabling sizes supplying them.

Replacing an existing unit vs cable size
Showers up to 7kw may carry a 6mm cable as long as the shower unit is within 18 metres of the consumer unit. Fuses and switches should be rated at 32 amps.Showers up to 8.5kw may carry a 6mm cable as long as the shower unit is within 18 meters of the consumer unit. Fuses and switches should be rated at 40 amps.Showers up to 9.5kw carry a 10mm cable to units within 35 metres of the consumer unit. Fuses and switches should be rated at 45 amps.

Showers up to 12.5kw should carry a 10mm cable to units within 35 metres of the consumer unit.

Fuses and switches should be rated at 50 amps.

In all cases the circuit should be interrupted by a double pole pull cord switch with a neon on/off indicator and a mechanical indicator should the neon fail.

It is essential, in all cases, that the shower supply pipes are independently cross bonded to earth.