best shower system

Selecting the right shower

Making the right choice. With over thirty years manufacturing experience in the brassware and shower markets, Deva brings a wealth of knowledge to the UK shower industry.

Using this guide, our aim is to help you choose the very best shower for your application. In our experience many users select the highest profile product, regardless of its suitability because they are unaware of the options available, such as high performance mixer valves, shower pumps etc.

In order to make the most informed choice regarding your new shower and be sure you’re getting the best you can afford, you’ll need to understand the different showering options available and the type of plumbing system installed in your property.

Hot water for showering is provided either by a stored hot water system or by an instantaneous heater of some description that heats the water on demand. One could argue therefore that; ‘in general terms’, that there are only two different types of showering system:

Instantaneous electric shower

A direct acting appliance such as an electric shower, which heats the water as it is drawn through the unit.

Mixer valve shower

A shower that uses the same water system, that feeds your taps in the bathroom, kitchen, and utility room etc. Often referred to as a mixer shower.

However, hot water heating systems can also be divided into two ‘generic categories’:

Water that is heated; for example by an electric element (emersion heater) or a separate heating boiler; and then stored in a cylinder (which traditionally formed the airing cupboard)

Water that is heated on demand via an instantaneous boiler commonly known as a combination or multipoint type boiler.

Combination or instantaneous water heating boilers now account for approximately 50% of the UK, water and domestic heating market. Therefore when deciding which shower to choose you will need to consider three main options, follow the links to gain a brief over view of the benefits and pitfalls of each type of showering solution.

Instantaneous direct acting electric showers

Electric showers

electric showerElectric showers are the easiest showers to install in terms of compatibility with existing water heating systems and locations throughout the home. They draw water direct from the mains water supply and heat it as it is used for showering.

It can be used in most domestic showering applications e.g. over the bath, shower cubical’s, shower rooms etc.

(Redring Colour Moods shower shown)


Provides a shower that is independent of the main hot water heating system in the house, thus reducing the risk associated with breakdowns.

Can be installed in almost any home throughout the world new & old.
Instantaneous shower; it can be used at any time of the day.


Requires electrical wiring from the shower unit to the main fuse box.
Flow rate tends to be lower than showers that use the homes main water heating system, and it will vary between summer when the incoming water is warm, and the winter when the flow rate will reduce because the incoming water is significantly colder..

Cost wise, the installation costs may be higher than showers that use the homes main water heating system due to the need for plumbing and electrical work.

best electric showerHigher kilowatt output showers have gone a long to help overcome some of the disadvantages of poor flow; (10 kilowatt showers are the equivalent of over 3 emersion heaters or 10 x 1 kilowatt bars on an electric fire) but to some an electric appliance fitted in the bathroom is perceived as a safety risk.

This is not the case, providing it is properly installed, by a trained professional who knows what he is doing.

Electrical appliances are often associated with water for example the kettle, washing machine or the electric cooker, which needs frequent washing.

If this is the shower solution for you make sure its fitted correctly and use a reputable brand that has an established reputation within.

(Mira Sport shown – link here)

Tankless water heater or Mains pressure showers

Showers that are fed from a domestic heating system that feeds hot water to the taps instantaneously on demand.

Combination boilersCombination boilers have become increasingly popular over the last 10-15 years as the number of one and two person homes as increased dramatically.

The combination boiler takes the practicality of an instantaneous ‘Multipoint’ water heater and combines it with a traditional boiler, hence the name ‘combination’ boiler. The great advantage is that you only use the water that you need.

You can establish whether you have an instantaneous boiler by the lack of any storage water cylinders. A simple test is to turn the central heating off, so that the boiler is not running; then turn a hot water tap on, the boiler should fire to supply water to the tap.

A combination boiler will switch all its heat output to water heating when demanded. This means that you will have a boiler capable of heating your whole house feeding your mixer shower.

DEVA Modern Thermostatically Controlled Exposed ValveTherefore if you have this type of water heating system you will need a shower that blends or mixes the hot and cold water to a safe showering temperature that can be maintained.

Mixer showers that are compatible with instantaneous boilers will have a higher flow rate than electric showers, and are generally easier to install because there are no electrical connections.
(DEVA Modern Thermostatically Controlled Exposed Valve Shown.)


High flow rates, similar to a powered shower because these showers are mains fed and designed for pressurized water systems.

Easy to install, no problems with system design, location or compatibility with your existing water system, providing you have an instantaneous boiler that has been installed correctly.

Instantaneous shower only heats the water when you need it.


If your boiler breaks down you have no hot water for your taps or showering.

Combination boilers start to heat water when a tap or shower is turned on. The length of pipe from the boiler to the shower determines the time taken for hot water to reach the shower, and it is often the case that large volumes of water need to be drawn off, before water of the correct temperature is achieved, this can be costly and frustrating. Good system design and installation helps to overcome this problem in most cases.

If this is the shower solution for you make sure its fitted correctly and use a reputable brand that has an established reputation.

Gravity Fed Mixer Showers

Showers that are fed from a stored hot water system, that can only feed hot water to the taps if the water has been pre heated in the cylinder.

Imagine a set of taps with a temporary, rubber, hand-shower attachment. The idea is very simple, you pre heat the water in your cylinder then turn the hot and cold taps to blend the water to achieve a comfortable showering or rinsing temperature. Mixer showers work on the same principal they are easy to install as they do not need any electrical connections, and work by blending hot and cold water together. They are ideal if you have an abundant supply of stored hot water.

The success of these types of shower is determined by the capacity of stored hot water that is available, and from a users point of view, the flow rate of water that is achieved from the shower rose. I shall attempt to explain without over complicating the issue.

The water flow rate from the shower head – GPM

flow rate of waterImagine a container of water with a hose connected to the bottom of it. If you hold the end of the hose above the level of water in the bucket no water will come out.

If you hold the hose just below the level of water in the container the water will come out, but it can be held quite easily by squeezing the end of the hose. The pressure of water is low because the water is almost finding its own level.

Now let the hose fall to its lowest point. This time the water has a high flow rate and it is difficult to squeeze the pipe to stop the flow of water. The pressure of water is high because it is free to run and because it has the whole weight of the water in the container forcing the water out.

This is commonly referred to as the head of water: the difference between the bottom of the water header tank and the water outlet i.e. the tap of shower head. The bigger the difference the faster the water comes out, it’s as simple as that.

To find out if you have gravity system; first check to see if you have a lagged ‘hot water cylinder’, these are most commonly located within an airing cupboard.
Secondly check to see if you have a ‘cold water storage tank’, this will most likely be situated in your loft or in older properties, perhaps in the top of a cupboard within your bathroom.

water gravity systemWith a gravity system, cold water from the mains water (1) is piped into a ‘cold water storage tank’ (2) usually located within the loft space.

Using the principal of gravity the water flows to feed the hot water cylinder (3) then when a tap or shower(4) is turned on, water is allowed to flow around the system under the ‘head of pressure’ created by the cold water storage tanks (2) location. Therefore the higher your cold water storage tank the greater the pressure available = and a more powerful showering experience.

Shower pumps

mixer shower for use on a gravity systemWhen selecting a mixer shower for use on a gravity system, the most important thing to consider is the flow rate that is achievable from the shower rose. Unless you have water pressure of at least 0.5 bar, which is equivalent to a gap of five meters between the bottom of the cold water storage tank (2) and the shower rose (4) you will need to select a ‘Low Pressure’ shower valve, capable of supplying a satisfactory shower at water pressures as low as 0.1 bar, (which is approximately one meter difference).

You will be able to get a rough idea simply by observing the flow rate of water that you receive from the bath taps. Remember that you will be mixing hot and cold water but if it appears slow then the chances are that the showers performance will be disappointing.

The solution is to fit a shower pump that pushes the water to your shower mixer thus creating an invigorating powerful showering experience.

The capacity of stored water.

If you opt for the pumped solution you must ensure that you have plenty of hot water storage capacity, for pumped showers can deliver anything between 11 – 25 Liters of blended water per minute, and this will drain the average sized cylinder very quickly.

You will have an idea of the amount of hot water that you have available by looking at the physical size of your cylinder and monitoring your everyday usage. For example the depth of hot water that you are able to achieve when running a bath before the hot water runs out.

If you do not have large volumes of stored water, do not use a pump unless you alter the system to cope with it. Alternatively fit an electric shower.

HVAC heating and Air Conditioning

The HVAC system uses three closely related functions, namely, heating, ventilation, and air-conditioning. These functions are uniquely set up so that they can regulate temperature and humidity in residential homes, public offices, and other building facilities with respect to the overall design of the structures.

Also keep in mind that a lot of variables are also needed to be calculated when looking into the best HVAC system for your use. Things like extreme weather conditions where your dwelling is located, if it is furnished and what kinds of furnishing it includes, if you have insulated glass, window treatments that trap heat or other discount cellular shades, the amount of use it will get (the human body creates heat at all times.

These are things to consider.


Most modern structures in colder regions in the world and in countries with temperate climate such as the United Kingdom usually install a heating system. This mechanism is used to regulate temperature in residential homes, public offices, and other dwellings.

The heating system can either be central or local. The most commonly used setup is the central heating system where the heating is concentrated in one area—central—and is then circulated for various heating processes and applications.  Heat values of fuels are based on BTU to cubic foot measurement for HVAC.

In the central heating system, there are three common components used. A furnace is an enclosure used for heating and can be found at the basement or at the attic. Different cultures have various interpretations of “furnace.” For the Americans, it is similar to kiln while for the British, it is equivalent to industrial furnaces.

Whatever it may be, it still uses the same principle for heat distribution—that is, it transfers heat using an intermediary distribution system. A boiler, meanwhile, is a type of furnace—in fact, a closed vessel—that distributes heat through steam.

Thermodynamic principles are the bases for a heat pump. This device causes the temperature to rise through heat transfer. A heat pump is very effective especially for very cold air since it has the ability to heat it at the shortest period. An efficient heat pump uses lesser energy and thus power.

A radiator is a heating device that circulates steam or hot water through pipes found inside an upright metal structure. This term is also commonly applied to some types of heat exchangers. It is a common perception among people that heat is transferred from a heat exchanger through radiation when, in fact, it is not. It transfers heat by convection, which uses currents.

Please note, though, that the central heating system is completely different from your hot water supply. For instance, the water used in the former is not the same as your tap water.

Ways of Central Heating

There are a number of methods for central heating. In electric heating, an electrical heater is used. It is a device that transforms electrical energy into heat.

Every electric heater contains an electric resistor, which acts as its heating element. Right now, there are many variations of electrical heaters that deliver different amounts of heat, but all of them use the same principle: Joule heating.

An electric current that converts electricity to heat is allowed to pass through the resistor. In hydronic heating, heat produced is commonly transferred to fins found along pipes in baseboard HVAC registers. You can also use coal, propane or natural gas, pressurized oil, or earth, which is used as a heat pump.


Over the years, air-conditioning has changed home lifestyle. A lot of London homes right now take advantage of wall-mounted air-conditioning systems. They are often placed in the living room, bedroom, kitchen—in almost all over the house.

Most buildings and offices also have hidden condensing units. Cooled places become refuge to those who are tired with the rising temperature outside.

There are various air-conditioning systems in the market, but they all function just the same. They control temperature, ventilation, and humidity in an enclosed environment. Hilsch air-conditioning uses a vortex tube called Ranque-Hilsch vortex tube for cheap spot cooling when you there is compressed air. However, it is not as efficient as usual air-conditioning equipment.

It is advisable that homes, buildings, and other offices have sealed windows to maintain the quality of air produced by the system. Furthermore, it is better to check the dwelling first to make sure that air conditioners can really be installed since they often use large ducts.

But you really don’t have to worry too much if it isn’t. You can still take advantage of remote coils or use the split system. Yet it is always preferable to maintain the cleanliness of the ducts to prevent the growth of pathogens that can definitely cause illness. Sometimes chemical monitoring of HVAC systems is needed to always ensure indoor air quality.

Seawater Air-conditioning

Ever heard of seawater air-conditioning? The seventies brought an energy crisis that drove scientists, engineers, and other concerned individuals to focus their minds on a much-cheaper energy source alternative.

Thus, they considered developing an air-conditioning system using seawater.

Initial studies, however, encountered a lot of problems. First of all, the cost for SWACS (seawater air-conditioning system) was not yet properly determined because the appropriate pipelines needed were not yet built.

To make matters worse, there were still a lot of unknowns with regard to the heat exchangers. Through continuous studies, OTEC (Ocean Thermal Energy Conversion) was able to develop more useful and reliable types of pipelines and heat exchangers.

Fundamentals of SWACS

Cold seawater can be taken from the bottom of the ocean or from the lakes. Other specific places like Hawaii and Fort Lauderdale and Miami in Florida are also favorable spots.

SWACS makes use of the following main components: a heat exchanger, freshwater distribution system, and seawater supply system. For maximum efficiency, you can adjust these three factors to suit the climate, location, and type of facility this system is installed.

Cold water is pumped deep either from the ocean or from the lake. It then passes through a heat exchanger, which is usually contained in a cooling station.

It is now the heat exchanger’s job to transfer heat from the freshwater distribution loop to produce cold water, which will be later distributed all throughout the building for air-conditioning.

Sometimes it is economical and practical to use auxiliary chillers. To supply deep cold seawater to maintain minimum temperature is, more often than not, impossible or remote.

First, seawater cools the chilled freshwater using a heat exchanger; then an auxiliary chiller is used to secondarily cool it.

As long as the coolness of the condenser is maintained, it can work efficiently.

Benefits of Seawater Air-conditioning

SWACS functions similarly to a conventional air-conditioning system. However, if it comes to economic savings and environmental friendliness, SWACS is a better choice.

SWACS can help you save approximately 90 percent of energy used. In most companies, air-conditioning cost is quite huge, approximately two-thirds of which is for chillers’ and cooling towers’ operations. SWACS’s chillers last longer than that of a conventional air-conditioning system. Moreover, it hardly depends on any future price changes of energy. But it should be noted that though this system has low operating cost, it has a high capital cost.

The use of SWACS also minimizes pollution and greenhouse effect.  This system doesn’t depend on fossil fuels, reducing air pollution and acid rain. It also prevents greenhouse effect since it uses a simple heat exchanger instead of a CFC-producing chiller machinery. CFCs (chlorofluorocarbons) cause the continuous depletion of our ozone layer.

Viability of SWACS

Site location is one of the major factors that determine the overall viability of SWACS. Others are the following:
·    Air-conditioning load size
·    Utilization of the air-conditioning system
·    Electrical costs
·    Onshore distribution system
·    Distance offshore to cold water

SWACS is one of the most vital energy source alternatives because of its economic and environmental benefits.

Though the system is not altogether perfect, it has potential in helping us curb the continuing rise of energy prices. What’s more, we can keep our own planet Earth clean, free, and safe for all of us to live in.