Shower system

Abstract

A shower 100 comprises a variable temperature setting means, e.g. an electrical heating element 106 or a mixer (132, figure 2) to produce shower water at a system temperature, and an electronic contro

Description

The present invention relates to shower systems, as may typically be used in residential bathrooms, or in commercial premises such as gymnasiums, swimming pools, campsites or anywhere where electric or mixer showers might be used. More particularly, it relates to shower systems that have electrical controllers for controlling the temperature, including electric showers where an electrical heating element is used to heat an incoming cold water supply, and to mixer showers having an electronic control of a mixer valve used for mixing hot and cold incoming water supplies to provide shower water to a user, where there is a desire by the homeowner, or shower operator, to reduce energy usage of the shower system. Electric showers are ubiquitous in households and other places, due to their convenience in providing a quick source of hot water, for as long as required. Mixer showers, where a source of pre-heated hot water is mixed with a cold water source, to produce water for showering at a desired temperature, are also commonplace. These showers often have a manual mixer that sets the temperature of the shower water. Electronic mixer showers are now becoming commonplace, where an electronic circuit is used to control a mixer valve and so control the shower water temperature. In the UK it is commonplace for a residential property to be assessed for its energy efficiency, and a “Standard Assessment Procedure” (SAP) score can be produced that provides an efficiency rating for the property. Other countries have similar schemes. The UK SAP scoring is currently based on a six minute shower. A shower is rated dependent upon its nominal power rating, and also its water flow rate and so by reducing these, the SAP score can be improved. However, there is a reluctance for users to have colder showers, or showers with a weaker flow rate, as they may see it as uncomfortable. Therefore, higher flow showers, using more energy, either electrical heating energy, or an increased usage of hot water from a hot water tank, are still popular. This leads both to a more expensive shower experience, and to a poorer energy performance. Embodiments of the invention have the object of addressing one or more of the above shortcomings of the background art, and / or to provide an alternative shower system. According to a first aspect of the present invention there is provided a shower comprising a variable temperature setting means for producing shower water at a system temperature, and an electronic controller for controlling the variable temperature setting means, wherein the controller is arranged to: without input from a user, adjust the variable temperature setting means so as to reduce system water temperature provided at the output of the shower by a small amount at a time point after the start of the shower, and for at least some of the remaining duration of operation of the shower. The variable temperature setting means will typically be a power modulator arranged to control the flow of electricity to an electrical heating element arranged to heat water from a cold water source connected thereto, but may also be an electronically controlled mixer unit arranged to mix a hot water input and a cold water input to provide water at an output having a system temperature between that of the two inputs. Such electrical heating elements, incorporated into the water flow, to form an electrical water heater, are commonplace in shower systems, and will be known to the skilled person. Similarly, electrically controlled mixer showers are also commonplace, and are often used in environments such as swimming pools, gymnasiums, commercial shower, and of course in residential properties also. It has been found that by reducing the energy usage of a shower by reducing the system water temperature by a small amount at some point after the start of the shower, particularly once the user has become accustomed to the temperature, then it can be done without having any significant impact on the quality of the shower as perceived by the user. Indeed, it may not even be noticed at all. Body skin temperature tends to increase during the early part of a shower, which may also contribute to the subsequent reduction in temperature being less noticeable. In some embodiments the controller is arranged to provide a first output water temperature, as chosen by a user, and at a time point where a user will be deemed to have become accustomed to the temperature, to reduce to a second temperature that is judged to be not, or barely perceptibly different from the first temperature by the user. The perception of the user is such that, by allowing them to become accustomed to the first temperature, a slight reduction is not noticed, or is barely noticed, and a saving of energy is made. This saving (over the cost of a shower not implementing this embodiment) increases the longer the shower goes on for. There may be, in some embodiments, a temperature sensor, such as a thermocouple, or a temperature dependent resistor, or some other temperature sensor, located so as to be able to measure the temperature of the water as it exits the heating element or mixer (depending on whether the shower has electrical heating or a mixer). Thus it is able to provide to the controller the temperature as will be experienced by the user of the shower, so that the controller can use the measurement to control the system water temperature. Some embodiments may have multiple temperature sensors, for example a sensor within the heating element (where present), so that the controller can determine whether the water within the heating element has reached the desired temperature for operation of the shower. Temperature sensors may be at other locations, such as in the shower cubicle in which the shower is installed, or in a shower hose, or in one or more water inlet pipes, so that the controller knows the temperature of the incoming water. The one or more sensors may be connected to the controller via a wired connection, or may use a wireless connection protocol, such as Bluetooth, WIFI, or Zigbee, or some other Note that the system water temperature is the temperature of the water provided to the user, as selected by the controller. This may differ from a demanded temperature (i.e. the temperature as selected by the user), due to the controller providing adjustment of the temperature according to some embodiments described herein. In some embodiments the temperature change may be controlled not by monitoring temperature, but by instead (for electric showers) reducing the power provided to the heating element, by an amount likely to create the desired reduction in system temperature. Similarly, for mixer showers the temperature may be changed by instructing a mixer valve to adjust the ratio of hot to cold water being allowed through. Preferably however there will be at least one temperature sensor within the system. In some embodiments the time point at which the temperature is changed is between 30 seconds and 4 minutes into the shower duration. This range has been found to allow the temperature to stabilise, and for the user to become accustomed to it. Preferably, in some embodiments, the time point is approximately 2 minutes into the shower duration. In some embodiments the temperature reduction is between approx.. 0.5 and approx. 2 degrees Celsius. This has been found to provide a power saving, whilst being generally not noticeable at the smaller reduction, and only marginally noticeable at the larger reduction. In some conditions, such as if the room is warm, a larger reduction may be attainable without being perceived by the user. In some embodiments the reduction may be set to 1 degree Celsius. The degree of reduction may, in some embodiments, be adjustable by the user. The degree of reduction may be, for example, 0.25°C, 0.5°C, 1°C, 1.5°C, 2°C, 3°C, 4°C, or more, or anything in between. Temperature reductions within the range of up to around 4°C have generally been found to be either not perceptible, or barely perceptible by users. In some embodiments the reduction may be selectable by the user, and may range from a very slight reduction, such as 0.5°C, all the way to an unheated shower, if desired. In some embodiments the temperature reduction is performed in a gradual manner over a duration of between 15 seconds and 2 minutes from the time point. Preferably, it may occur over the interval of approximately one minute. This makes the change even less noticeable to the user. In some embodiments the shower may further incorporate a mechanical, hydraulic or pneumatic driver that couples to the hose, and hence to the nozzle, that is arranged to control, under direction from the controller, the nozzle, and how many outlet holes are active at any one time. The driver may be, for example, a servo motor attachable to a cable drive, or a hydraulic or pneumatic device arranged to vary the fluid pressure down a control pipe. Thus the effective pressure within the shower hose may be adjusted accordingly, with higher pressures being associated with few active outlet holes, and lower pressures being associated with a greater number of active outlet holes. The nozzle may have an internal adjustable shield or plate that is moveable between positions, and in one position a greater number of holes are open and active as opposed to another position. The mechanical, hydraulic or pneumatic coupling may therefore be arranged to attach to the shield to change its position according to the driver within the shower. In some embodiments, following a period of running the shower at a reduced system temperature, the temperature is increased back to the initial system temperature. This may be done for example to provide an improved shower experience at the end of the shower when a user will be typically be rinsing soap from themselves. Some embodiments of the shower may incorporate a means for pumping air into the water flow. It has been found that doing so can provide a perceived increase in water pressure for the shower user. Advantageously, in some embodiments arranged to control an electrical heater, the electrical power to the heater is controlled using a pulse-width modulation technique. This allows for a fine power control, using, for example, a solid state relay, or thyristor control of the electrical power, and thus also fine control over the output water temperature. In some embodiments having an electrical water heater, when a user issues a command to the shower to switch it off, the controller is arranged to maintain the flow of water for a short time, with the electrical power to the heating element switched off. The duration of the extra water flow following the command is chosen so that the hot water within the shower system (comprising the shower hose, and in the heating element and output pipework), is passed through to the user, and it detects or estimates that cooler water is about to be exiting the nozzle and then stops the water flow and switches off. In this way, the water that has been heated by the shower is not wasted. In some embodiments a cold water inlet pipe of the shower is arranged to connect to a waste water heat recovery unit. A waste water heat recovery unit sits in the waste water flow path, and acts as a heat exchanger, with the waste water being used to pass its residual heat to incoming water. When installed so as to provide water to the shower unit then it will provide a warmer cold-water feed to the heater, and so less energy is required in providing water at the system temperature. According to a second aspect of the invention there is provided a shower controller, comprising a variable temperature setting means for producing shower water at a system temperature, wherein the controller is arranged to, without input from a user, adjust the variable temperature setting means so as to reduce system water temperature provided at the output of the shower by a small amount at a time point after the start of the shower, and for at least some of the remaining duration of operation of the shower. In some embodiments the shower controller may be installed within a shower unit, such as an electric shower unit as typically found in many homes in the UK. The controller may, in embodiments used to control a mixer shower, be fitted with, or nearby a mixer valve used to control the relative proportions of hot and cold water. In some embodiments the controller may be installed remotely from the shower that it is arranged to control. In this way, a simple retrofit of a power switch is all that is needed to provide an electric shower with the functionality according to the invention, without modifying the shower itself. This is because the controller, being electrically connected to the shower, can detect (from the current drawn by the shower) when a shower starts, and can reduce the power being supplied by modulating the supply. As electric showers use resistive heating elements then the modulation of the supply acts to reduce the energy supplied to the heating element, resulting in less heating, and hence a cooler shower. The controller may have a timer so as to be able to choose a time, after the start of the shower, when to reduce the power to the shower, and hence reduce the temperature of the water going to the user. Conveniently, in some embodiments, the controller is built into an isolating power switch arranged to supply electricity to an electric shower. In some embodiments the controller may be fitted between an isolating switch, and the shower itself. It may then work as described above. In other embodiments the controller may be fitted within the shower itself. In other embodiments, it may be fitted before an isolating switch, or in other words, electrically between the isolating switch and an electrical supply coming into the property. Advantageously, the variable temperature setting means may in some embodiments comprise a power modulator arranged to modulate the electrical power supplied to a shower heating element. The modulator may be arranged to provide pulse width modulation of the power. The modulator may comprise a solid state relay, a triac, or thyristor, solid state relay, or any other suitable type of power controller. In certain embodiments where the controller is located remotely from the shower (such as in an isolation switch unit), there may also be an auxiliary interface module (AIM) located within the shower assembly, which may be either retrofitted, or built in to the shower in factory. The module is configured to condition power and signals for existing actuators or electronic mixer components, including solenoid-actuated valves such as a water-inlet solenoid. This may be desirable if some of the shower elements, such as said actuators do not behave in a desired way with reduced power levels created by modulation of the incoming power as provided by the shower controller. The AIM may include an energystorage element, such as a capacitor or battery, to provide short-duration power ride-through during supply modulation. It may also act to smooth, or current-shape incoming electrical power to reduce audible noise and undesired pulsation of the actuators. Communication between the AIM and the remote controller may be wired or wireless, and the module may be powered from existing shower circuitry. Locating the AIM proximal to an actuator within the shower can improve control stability and reduce audible artefacts. In some arrangements the AIM may provide a bypass or fail-safe state so the shower reverts to native operation on loss of power or communications. The controller may also be used with electrically controlled mixer showers, and may be arranged to control a mixer valve used to determine the ratio of hot to cold water supplied to a connected shower head. The controller may be arranged to control the valve to reduce the system water temperature after a time period after commencement of the shower, as explained above. The controller may be installed along with, or alongside the valve, or may be located remotely, and connected thereto using a wired or wireless connection protocol. Preferably, for use with mixer showers, the controller may further comprise a water flow detector for determining the start of a shower. The flow detector may be remote from the controller, and may be connected thereto by wired or wireless means. Alternatively, the flow detector may be contained within the controller, where the controller is mounted suitably proximal to a feed to the shower. For both the electric and the mixer shower variants the controller may have one or more sensors, such as temperature sensors arranged to measure system water temperature delivered to the user, and / or the room temperature. The temperature sensors may be wired to the controller, or may be in communication therewith wirelessly, using, for example the protocols mentioned elsewhere herein. The temperature sensors may be used to select, or influence, the time point at which the controller is arranged to make a change to the system water temperature. The sensors may also be arranged to select the amount of temperature change made to the system water temperature. For example, in a warm shower room, as determined by a room temperature sensor, the degree of temperature change may be slightly increased, without affecting the water temperature change perceived by a shower user. A change in temperature may also be made sooner into the shower. Likewise, on a cooler day, the system temperature change may be smaller, or may be made later in the shower duration. The remote controller may be pre-programmed with different algorithms. One example may start a timer when current flow, or water flow, if a flow detector is installed, is detected, and may base its temperature reduction based on the timer. Others may start a timer when current is detected, but also use temperature information to adapt the timing of how it changes the water output temperature based on the temperature readings. Others may monitor input water temperature particularly if a waste-water heat exchanger is being used, as that will tend to warm the incoming flow as the shower progresses, allowing energy to be reduced. Note that features and elements of the first aspect may be applied, where appropriate, to the second aspect of the invention, and vice versa. For both aspects, a temperature sensor may be arranged to monitor a water input temperature. This may be done for example to reduce the electrical power provided to an electrical water heating element if the input water temperature rises, whilst maintaining a desired system water temperature. Similarly, a mixer valve may be adjusted accordingly. Such water temperature changes can occur for various reasons as would be appreciated by a normally skilled person, but one significant one is the use of waste-water heat recovery systems, whereby the shower water may drain via a heat exchanger, to impart its residual heat into an incoming water flow feeding the shower. Embodiments of the invention are further described hereinafter, by way of example only, with reference to the accompanying drawings, in which: Figure 1 diagrammatically illustrates, at a high level, the elements of a shower according to an embodiment of the present invention using an electrical heating element; Figure 2 diagrammatically illustrates, at a high level, the elements of a shower according to another embodiment of the present invention using a water mixer unit; Figure 3 shows a graph of system water temperature versus time of an embodiment of the invention that reduces the system water temperature in a phased manner during the shower; and Figure 4 shows another embodiment of the invention, whereby a shower controller is located remotely from an electric shower that it is controlling. Shown in Figure 1 is a top level block diagram of components in an embodiment of the invention. These components are contained in a shower unit located in a shower, as is typical of electric showers currently. There are of course other components that would be required to implement a practical shower system, such as safety circuitry, power conditioning etc. that would be appreciated and understood by a person skilled in the art. The shower 100 comprises of a water inlet 102, that comes from a cold water supply, and a water outlet 104 that connects in use to a shower hose. The water inlet 102 feeds a water heater 106, that is arranged to heat the water to a system temperature as determined by a controller circuit 108. The controller circuit 108 has an electrical input (not shown), and an electrical output feed 110 to a heating element within the water heater. When the circuit 108 provides a suitable power supply to the heating element the water within the heater will be heated up, according to well known principles. A temperature sensor 112 is fitted to the heater, and is able to measure the temperature of water present therein. It is located such that it reads the water temperature at the output of the heating element. The heater has an outlet pipe 114 through which the heated water can flow when the shower is activated. The controller further has an On / Off switch 118, and a temperature setting knob 120. The switch 118 is used by a user to activate the shower, i.e. to start and stop the flow of water, and the temperature knob 120 is used to set a desired user water temperature. The temperature of the water at the output is under the control of the controller 108, and this is known herein as the system water temperature. Figure 2 shows a further embodiment of the invention. A key difference between this embodiment and that of Figure 1, is that the hot water is provided by a connected hot water source, rather than having an internal water heater. In more detail, the shower unit 130 comprises an electromechanical mixer unit 132 having a first input 134 from a hot water source, such as a hot water tank, and a second input 136 from a cold water source, and having an output 138. The shower further comprises a controller 140 and a temperature sensor 142 The output 138 from the mixer unit comprises of a mix of the two input water supplies. The mixer unit is an electromechanical device, that has a motorized mixing valve that is able to control the ratio of the two input water supplies that comprise the output water supply. The motorized mixing valve is connected to the controller 140, and the controller is able to adjust the ratio by providing appropriate control signals to the mixer. The temperature sensor, at the output of the mixer 132, connects to the controller, and enables the controller to set a desired output water system temperature, and to vary the system temperature as described herein. The operation of the shower according to the embodiment shown in Figure 1 will now be described, with reference to Figure 3. The shower is arranged to provide a saving of the energy used, as compared to a standard prior art shower, whilst still providing a fully satisfactory shower experience for the user. When a user enters the shower, they will select a desired water temperature using knob 120, and will then switch the power on using switch 118 (or they may do this in the reverse order of course). When they do this, the water will start to flow, and the controller 108 provides power to the heater through connection 110, to heat the water up to the temperature as chosen by the user. This can be seen at phase (a) of Figure 3, which is a graph of system water temperature (i.e. water temperature at the output of the shower), with time on the x axis. If the water temperature is significantly colder than the demanded temperature then the water heater will be driven at full power to bring it up to temperature as quickly as possible. As the water temperature at the output approaches the desired temperature then the controller will start to modulate the power provided to the heater so that the temperature does not significantly overshoot the demanded temperature. When the demanded temperature is achieved at the output of the heating element the controller will provide suitable electrical control of the heater to maintain this temperature, as shown at phase (b) of Figure 3. It uses the temperature sensor 112 to measure the water temperature, and so a feedback system is employed. This then is the current system temperature of the shower, and so the system temperature is the same as the temperature demanded by the user. Stage (a) of the process typically takes place in a few seconds. After a period of two minutes from the start of the shower, the controller then starts a power saving process, whereby it slowly reduces the power supplied to the heater, so as to bring the system temperature down by around 1 °C from that of the demanded temperature. This is shown at phase (c) in Figure 3, with the system temperature ramping down over the duration. It does this over a period of one minute in a broadly linear fashion. It has been found that such a reduction, if done in this graduated manner, is typically not noticeable by a user of the shower. Therefore, for the rest of the duration of the shower, i.e. during phase (d), there will be a lower electrical draw due to the reduced effort required to heat the water to this lower system temperature. It will be apparent that the description above of the operation of the embodiment of Figure 1, applies, mutatis mutandis, to the embodiment of Figure 2, but with appropriate changes to the apparatus for providing the heated water for the output of the shower. Where the controller acts to reduce the power provided to the heating element of the embodiment of Figure 1, it will instead adjust the mixer unit to provide a greater ratio of cold water to hot water at the mixer output in the embodiment of Figure 2. Figure 4 shows another embodiment of the invention, comprising a shower controller 170. In this embodiment, the shower controller 170 is arranged to control a standard (unmodified) electrical shower 172, of the type commonly available, that has a resistive electrical heating element therein. The shower 172 (which is not part of the invention in this embodiment), has a cold water feed 174, a hot water delivery hose 176, and an electrical supply from a property mains circuit cable 178. It further has standard controls for temperature, on / off etc. It is normal for an electrical shower to have an isolation switch, usually ceiling mounted in the shower room, or nearby, to provide electrical isolation when required. In this embodiment, a standard isolation switch has been replaced by the controller 170, which also incorporates an isolation switch, so performing a dual function. Controller 170 comprises, as well as an isolation switch, a timer circuit and a power modulator. The controller provides the power through cable 178, and in turn is connected to a property mains circuit 182. The controller is able to detect, from current drawn through cable 178, when a shower is activated. When the isolation switch is activated in a configuration to provide electrical power to the shower, the controller connects power from circuit 182 through to cable 178. The current drawn will, when the shower is not being used, be very low, or may be zero. A user, entering the shower and operating the on / off control to activate the shower will cause a significant current to be drawn from the mains supply 178 and 182. The controller is arranged to detect this current draw, and when detected, to start a timer circuit. When the timer circuit has reached a predetermined time interval, such as 2 minutes (or other such time as details for other embodiments herein), the controller starts to modulate the power delivered to the supply 178, to reduce the overall RMS current drawn. As the shower has a resistive heating element, this will reduce the power drawn by that heating element, and so also reduce the temperature of the water at the output of the heating element supplied to hose 176. This reduced power and temperature of course reduce the power consumption of the shower unit in similar fashion to other embodiments of the invention. After the shower has finished, as detected by the current reducing to zero (or close to it), the controller again applies an unmodulated mains signal to cable 178, ready for the next shower, and the timer resets. Figure 4 also shows some optional temperature sensors, that may be used with this embodiment, or with other embodiments discussed herein. Temperature sensor 184 comprises of the temperature transducer itself and a low power transmitter that is in communication with controller 170, and is arranged to send temperature information thereto. The sensor 184 is arranged to measure the temperature of the water supplied to the user of the shower, within the shower hose. Sensor 186 is arranged to measure the temperature in the shower room or cubicle, but not to measure water temperature. Again, it is arranged to send its reading back to controller 170. A third sensor is located to measure the temperature of a cold water feed to the shower. As stated above, the cold water temperature may vary, sometimes considerably, through natural variations as the water is drawn from underground pipes, or through the use of waste-water heat recovery systems. If the input temperature is seen to increase, then the power feeding a heating element in an electric shower can be reduced while maintaining the same system temperature. Sensor 184, arranged to measure the water temperature to the user of the shower, can be used to provide feedback on changes to the power supplied to the heating element, so as to maintain a desired system temperature. Sensor 186, measuring the room temperature, can be used to provide a guide to the controller on how much of a temperature reduction can be done before the temperature drop is likely to be perceived by the user. In a hot room, for example in summer, or in a well heated house, then a larger drop can be made (with more of an energy saving), than if the room is colder. It will be appreciated that the temperature sensors can function and be used with a controller for a mixer shower, as well as an electric shower. There, the controller will receive temperature information from the sensors and use it to control a mixer valve to set 5 the temperature of the water supplied to the user. Different embodiments may use any one, any two or all three of these temperature sensors, or may not use any temperature sensors, but instead may rely on estimated temperature reductions of water caused by known reductions in power levels, e.g. as supplied to an 10 electrical heating element. The reductions in temperature provide measurable reductions in power drawn from the electrical system once they have cut in. A shower according to some embodiments of the invention, therefore provides benefits not just in being cheaper to run, but also in scoring 15 well on environmental assessments of properties that have such showers fitted. A typical shower generally follows three main stages: a) Wetting the body (starting the shower, getting wet), b) Lathering up (applying soap / shampoo and scrubbing), 20 c) Rinsing off (washing away soap and shampoo). For a typical 6 minute shower, this may comprise (with timings being approximate of course): Time (minutes) Activity 25 0:00-1:00 Get wet - Step under the shower, fully wet hair and body. 1:00-3:30 Apply soap and wash - Shampoo hair, soap body, scrub 3:30-6:00 Rinse thoroughly Rinse out shampoo and soap. Focus on hair, body, underarms, and feet. 30 It has been found that in some instances, where a shower user has a timer that shows their time spent in the shower, then the shower duration tends to be shorter. Some embodiments may have therefore a display on the shower unit that shows the duration of the shower. 35 The invention may be further understood from the following paragraph: A shower system comprises a variable temperature setting means for producing water at a system temperature and a controller, the controller being arranged to reduce the temperature of the water at a point after commencement of the shower. It also extends to a controller for a shower, where the controller may be remote from, and may control a standard shower A small reduction in the temperature or flow is often unnoticed by the shower user once they have acclimatized to the shower, and can resultt in a notable reduction in energy usage. This has benefits in electricity costs, as well as an improved house efficiency score under schemes such as the UK Standard Assessment Procedure (SAP). In the UK the SAP efficiency rating score can be improved an appreciable amount by use of a shower according to some embodiments of the invention, giving a significant benefit to those buying, selling or renting out properties. The SAP system of the UK allots a standard set of performance criteria to a shower, and under normal circumstances it treats all electric showers similarly. However, some embodiments of the invention deviate from the standard model by allowing an increase in SAP points during specific assessments. Features such as those described above provide energy efficiency gain over a standard electric shower, thereby boosting the overall SAP score. Further improvements in the SAP score can be obtained if a waste-water heat recovery unit is fitted, to extract the heat from waste water and use it to heat a cold water feed to the shower. The functions described herein as provided by individual components could, where appropriate, be provided by a combination of components instead. Similarly, functions described as provided by a combination of components could, where appropriate, be provided by a single component. Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Features, integers, or characteristics described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined 5 in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or 10 process so disclosed.

Claims

1. A shower comprising a variable temperature setting means for producing shower water at a system temperature, and an electronic controller for controlling the variable temperature setting means, wherein the controller is arranged to:without input from a user, adjust the variable temperature setting means so as to reduce system water temperature provided at the output of the shower by a small amount at a time point after the start of the shower, and for at least some of the remaining duration of operation of the shower.

2. A shower according to claim 1 wherein the system water temperature is initially, at the start of a shower, arranged to provide a first output water temperature, as chosen by a user, and at a time point where a user will be deemed to have become accustomed to the temperature, to reduce to a second temperature that is judged to be not, or barely perceptibly different from the first temperature by the user.

3. A shower according to claim 2 wherein the time point is between 30 seconds and 4 minutes into the shower duration.

4. A shower according to claim 3 wherein the time point is approximately 2 minutes into the shower duration.

5. A shower according to any of claims 2 to 4 wherein the temperature reduction is between 0.5 and 2 degrees Celsius.

6. A shower according to any of the above claims wherein the temperature reduction is performed in a gradual manner over a duration of between 15 seconds and 2 minutes from the time point.

7. A shower as claimed in claim 6 wherein the time period is approximately 1 minute.

8. A shower as claimed in any of the above claims, wherein, following a period ofrunning the shower at a reduced system temperature, the temperature is increased back to the initial system temperature.

9. A shower as claimed in any of the above claims wherein the variable temperature setting means comprises a power modulator arranged to control the flow of electricity to an electrical heating element arranged to heat up water from a cold water source connected thereto.

10. A shower as claimed in claim 9 wherein the electrical power is controlled using a pulse-width modulation technique.

11. A shower as claimed in any of claims 1 to 8 wherein the variable temperature setting means comprises of a mixer arranged to mix a hot water input and a cold water input to provide water at an output having a system water temperature between that of the two inputs.

12. A shower as claimed in any of the above claims and further comprising one or more temperature sensors, arranged to monitor at least one of a) a water temperature at an output of the shower, b) a water temperature at an input of the shower, and c) a room temperature, and further arranged to use measurements therefrom to adjust or maintain a desired system temperature, or time point at which the system temperature is changed.

13. A shower controller, comprising a variable temperature setting means for producing shower water at a system temperature, wherein the controller is arranged to, without input from a user, adjust the variable temperature setting means so as to reduce system water temperature provided at the output of the shower by a small amount at a time point after the start of the shower, and for at least some of the remaining duration of operation of the shower.

14. A shower controller as claimed in claim 13 wherein the controller is located remotely from a shower that it is arranged to control.

15. A shower controller as claimed in claim 14 wherein the controller is built into a power switch arranged to supply electricity to an electric shower.

16. A shower controller as claimed in any of claims 13 to 15, wherein the variable temperature setting means comprises a power modulator arranged to modulate the electrical power supplied to a shower heating element.

17. A shower controller as claimed in any of claims 13 to 16 and further comprising an auxiliary interface module, installable within a shower unit, and being arranged to smooth, or current-shape an incoming electrical supply from the controller.

18. A shower controller as claimed claim 13 or claim 14 wherein the variable temperature setting means comprises an electrical circuit arranged to control a mixer shower valve.

19. A shower controller as claimed in any of claims 13 to 18 claims and further comprising one or more temperature sensors, arranged to monitor at least one of a) a water temperature at an output of the shower, b) a water temperature at an input of the shower, and c) a room temperature, and further arranged to use measurements therefrom to adjust or maintain a desired system temperature, or time point at which the system temperature is changed.

20. A shower controller as claimed in claim 19 wherein the one or more temperature sensors are mountable remotely from the controller, and connectable thereto by wired or wireless mean.

21. A shower as claimed in any of claims 1 to 12 wherein a water inlet pipe of the shower is arranged to connect to a waste water heat recovery unit.

22. A shower as claimed in claim 21 and further comprising a waste water heat recovery unit couplable thereto.A

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