The kind of shower that can be installed depends partially on your homes water system. Where hot and cold water are both supplied from storage tanks at equal pressure, a mixer shower is largely the most economical choice. Many showers are intended to cope with differing waste pressures, such as stored hot water and cold mains water. If you connect mains water to a shower, you must fit a double seal check valve on the mains supply pipe to prevent back siphonage. Some showers come with built in check valves. Specially designed systems are necessary when hot water is to be supplied from the mains via a multipoint heater or combination boiler: check the installation requirements with the shower manufacturer.
Bath/ Shower mixer
A shower spray combined with a bath mixer tap provides a shower for little more than the cost of the bath taps, and no extra plumbing is involved. The temperature is controlled through the bath taps, which may not be convenient, and will be affected by water being drawn off elsewhere in the home.
Power shower
An all in one shower which incorporates a powerful electric pump that boosts the rate that hot and cold water are supplied to the shower head from the storage cistern and the hot water cylinder. A power shower is unsuitable where water is supplied from a combination boiler under mains pressure. Removing waste water from a power shower fast enough can be a problem. The shower tray must cope with around 27 litres a minute, so it is probably worth fitting a 50mm waste pipe.
Shower tower
A wall unit that incorporates a thermostatic mixer shower with a number of adjustable body jets. Tower units also have a fixed shower head and a hand held spray and may be designed to fit into a corner or on a flat wall. Some can be installed over a bath while others are made for cubicles or wet rooms. Most require a minimum ceiling height of 2.2m. A pump is usually needed to boost water pressure.
Instantaneous electric shower
A wall unit plumbed into a mains cold water supply, and heated by an electric element. The controls allow either less water at a higher temperature of ore at a lower temperature, so the spray is weaker in winter when mains water is colder. Some models have a winter/summer setting. Designs fitted with a temperature stabiliser cannot run to hot or be affected by other taps in use. The unit must be wired to electric power supply meeting Wiring Regulations.This type of shower can be installed where a mixer would be illegal. Where a mixer would be illegal. Where mains water pressure is too low, a tank fed pumped electric shower is available.
Safety warning:
Showerhead on a hose must be fed trough a retaining ring on the wall of the shower. This prevents the showered hanging in standing water in the bath or shower tray beneath and avoids potential contamination of the mains supply.
