Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens Siemens
SIWAMATPLUS5141 SIWAMATPLUS5201 SIWAMATPLUS5201 SIWAMATPLUS5203 SIWAMATPLUS5203 SIWAMATPLUS5203 SIWAMATPLUS5203 SIWAMATPLUS5203 SIWAMATPLUS5203 SIWAMATPLUS5203 SIWAMATPLUS5203 SIWAMATPLUS5241 SIWAMATPLUS5243 SIWAMATPLUS5243 SIWAMATPLUS5290 EXTRAKLASSE5293 EXTRAKLASSE5293 SIWAMATPLUS5301 SIWAMATPLUS5301 SIWAMATPLUS5331 SIWAMATPLUS5331 SIWAMATPLUS5331 SIWAMATPLUS5331 SIWAMATPLUS5331 SIWAMATPLUS5331 SIWAMATPLUS5331 SIWAMATPLUS5331 EXTRAKLASSE5393 SIWAMATPLUS5401 SIWAMATPLUS5403 SIWAMATPLUS5403 SIWAMATPLUS5403 SIWAMATPLUS5403 SIWAMATPLUS5403 SIWAMATPLUS5431 SIWAMATPLUS5431 SIWAMATPLUS5431 SIWAMATPLUS5433 SIWAMATPLUS5433 SIWAMATPLUS5433 SIWAMATPLUS5433 SIWAMATPLUS5433 SIWAMATPLUS5433 SIWAMATPLUS5433 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash+Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6120
WD51410JK/08 WD52010/01 WD52010FG/01 WD52030/01 WD52030/02 WD52030DC/01 WD52030DC/02 WD52030FG/01 WD52030FG/02 WD52030SI/01 WD52030SI/02 WD52410FG/01 WD52430/01 WD52430/02 WD52900/01 WD52930/01 WD52930/02 WD53010GB/01 WD53010GB/08 WD53310/01 WD53310/06 WD53310/08 WD53310DC/06 WD53310DC/08 WD53310FG/01 WD53310FG/06 WD53310FG/08 WD53930/02 WD54010GB/01 WD54030DK/01 WD54030DK/02 WD54030DK/03 WD54030GB/01 WD54030GB/02 WD54310/01 WD54310DC/01 WD54310FG/01 WD54330/01 WD54330/02 WD54330DC/01 WD54330DC/02 WD54330FG/01 WD54330FG/02 WD54330SI/02 WD61200/01 WD61200/11 WD61200/12 WD61200/13 WD61200DS/11 WD61200FF/01 WD61200FF/11 WD61200FF/12 WD61200FF/13 WD61200FG/01 WD61200FG/11 WD61200FG/12 WD61200FG/13 WD61200IE/01 WD61200IE/12
Wash&Dry6120 Wash&Dry6120 Wash&Dry6120 Wash&Dry6124 Wash&Dry6124 Wash&Dry6124 OPTIMA613D EXTRAKLASSEWT1300A WASCHTROCKNEREXTRAKLASSE EXTRAKLASSEWT1300A EXTRAKLASSEWT1300A EXTRAKLASSEWT1300A EXTRAKLASSEWT1300A EXTRAKLASSEWT1300A EXTRAKLASSE1300Wash&Dry Wash&Dry6140 Wash&Dry6140 Wash&Dry6140 Wash&Dry6140 Wash&Dry6140 Wash&Dry6140 Wash&Dry6140 Wash&Dry6140 Wash&Dry6143 Wash&Dry6130 Wash&Dry6143 Wash&Dry6143 Wash&Dry6143 Wash&Dry6143 Wash&Dry6143 Wash&Dry6143 Wash&Dry6143 Wash&Dry6143 Wash&Dry6143 Wash&Dry6143 Wash&Dry6143 WD61480GB SIWAMATPLUS4830ELECTRONIC SIWAMATPLUS4830ELECTRONIC SIWAMATPLUS4831ELECTRONIC SIWAMATPLUS4831ELECTRONIC SIWAMATPLUS4830ELECTRONIC SIWAMATPLUS4830EL SIWAMATPLUS4931ELECTRONIC SIWAMATPLUS4931ELECTRONIC SIWAMATPLUS4931ELECTRONIC SIWAMATPLUS4931EL SIWAMATPLUS4931ELECTRONIC SIWAMATPLUS4931EL SIWAMATPLUS4931ELECTRONIC SIWAMATPLUS4931ELECTRONIC SIWAMATPLUS4931EL SIWAMATPLUS4931ELECTRONIC SIWAMATPLUS4931EL SIWAMATPLUS4951ELECTRONIC SIWAMATPLUS4951ELECTRONIC SIWAMATPLUS4951ELECTRONIC SIWAMATPLUS4951ELECTRONIC SIWAMATPLUS4970ELECTRONIC SIWAMATPLUS4970ELECTRONIC SIWAMATPLUS4970ELECTRONIC SIWAMATPLUS5031ELECTRONIC SIWAMAT6102 SIWAMAt6102 SIWAMAT6102

WM50401FG/01 WM50401IG/01 WM50401SN/01 WM50430/12 WM50431/01 WM5047AEU/12 WM5047AGB/01 WM5047BEU/01 WM5047GEU/01 WM5057SEU/01 WM50601/01 WM50601FG/01 WM50601SN/01 WM50800/01 WM50800/11 WM50800EE/01 WM50800FF/01 WM50800FF/11 WM50800FF/12 WM50800FG/01 WM50800IE/01 WM50800IE/11 WM50800II/01 WM50800II/09 WM50800II/11 WM50800II/12 WM50800IL/01 WM50800IL/09 WM50800SN/01 WM50900/01 WM50900/11 WM50900FF/01 WM50900FF/11 WM50900FF/12 WM50900FG/01 WM50900GB/01 WM50900IE/01 WM50900IE/12 WM50900IL/01 WM50900IL/09 WM50900IL/11 WM50900SN/01 WM51000/01 WM51000/11 WM51000/12 WM51000FF/01 WM51000FF/11 WM51000FF/12 WM51000FG/01 WM51000FG/11 WM51000FG/12 WM51000GB/01 WM51000GB/11 WM51000GB/12 WM51000GB/14 WM51000GR/01 WM51000GR/11 WM51000GR/12 WM51000IE/01
SIWAMAT5100 SIWAMAT SIWAMAT5100 SIWAMAT5100 SIWAMAT5100 SIWAMAT SIWAMAT5100 SIWAMAT5102 SIWAMAT5102 SIWAMAT SIWAMAT5102 SIWAMAT5103 SIWAMAT5103 SIWAMAT SIWAMAT5103 SIWAMAT5103 SIWAMAT5103 SIWAMAT SIWAMAT5103 SIWAMAT5103 SIWAMAT5103 SIWAMAT SIWAMAT5103 SIWAMAT5103 SIWAMAT SIWAMAT5103 SIWAMAT5103 SIWAMAT5103 SIWAMAT5103 SIWAMAT5107 SIWAMAT5107 SIWAMAT SIWAMAT5107 SIWAMAT5107 SIWAMAT5110 SIWAMAT5110 SIWAMAT6080 SIWAMAT6100 SIWAMAT6100 SIWAMAT6100 SIWAMAT6100 SIWAMAT6100 SIWAMAT6100 SIWAMAT6103 SIWAMAT6103 SIWAMAT6103 SIWAMAT6103 BLUESTAR SIWAMAT6110 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120 SIWAMAT6120
WM51000IE/11 WM51000IE/12 WM51000SN/01 WM51000SN/11 WM51000SN/12 WM51020EU/01 WM51020EU/11 WM51020EU/12 WM51030/01 WM51030/11 WM51030/12 WM51030CH/01 WM51030CH/11 WM51030CH/12 WM51030FG/01 WM51030FG/11 WM51030IE/01 WM51030IE/11 WM51030II/01 WM51030II/09 WM51030II/11 WM51030II/12 WM51070/01 WM51070/11 WM51070/12 WM51070FG/01 WM51100SN/01 WM51100SN/11 WM60801IE/01 WM61001/01 WM61001FF/01 WM61001FG/01 WM61001IE/01 WM61001II/01 WM61002FF/01 WM61031/01 WM61031CH/01 WM61031FG/01 WM61031II/01 WM6107BEU/01 WM61101GB/01 WM61200/01 WM61200/11 WM61200/12 WM61200FF/01 WM61200FF/11 WM61200FF/12 WM61200FG/01 WM61200FG/11 WM61200FG/12 WM61200GB/01 WM61200GB/11 WM61200GB/12 WM61200SK/01 WM61200SN/01 WM61200SN/12 WM61201FF/01 WM61201FG/01 WM61201GB/01
SIWAMAT6120 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6123 SIWAMAT6127 SIWAMAT6127 SIWAMAT6127 SIWAMAT6127 festival FESTIVAL BlueStar BLUESTAR WASH+FIT SIWAMAT6127 FOURSEASONS SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6104 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6140 SIWAMAT6143 SIWAMAT6143 SIWAMAT6143 SIWAMAT6143 SIWAMAT6143 SIWAMAT6143 SIWAMAT6143 SIWAMAT6143 SIWAMAT61431 SIWAMAT6143 SIWAMAT6147 edition150 edition150 edition150 edition150 SYDNEY1400 SIWAMATIQ700 SIWAMAT7127Aquasensor

1 PRODUCT REVIEWS

1.1 Wet white goods Dish washers and Washing Machines
In 2001 77% of households own a washing machine and the growth in ownership seems to be levelling out. Meanwhile dishwasher ownership continues to rise from 6% of households in 1985 to 25% in 2001 [Environmental Change Institute (DECADE) in dti 2003]. With over 17 million washing machines in use, around 1.2 million reach the end of their life each year in the UK [Simon et al 2001]. We have looked briefly at price and performance issues of washing machines and dishwashers twice before. The first time was for the Agencys Conserving Water in Buildings Fact Cards and the second was for the Watersave Network review of water-efficient technologies. Graph 1 illustrates the usual assumed pattern of higher cost for more efficient machines which then allows a payback to be calculated. Whilst acknowledging this over-cost for efficient machines, we had previously argued that much of the extra cost is due to improved quality and features, with efficiency being a by-product of good design rather than a bolt-on feature that can have a direct cost attributed to it [Grant 2002]. The graph is based on 1997 data and shows that more expensive machines tended to use less water and achieved a higher 'total score' based on 'Which?' test criteria. The 'total score' was based on the following weighting: cleaning performance 36%, running costs, 18%, spinning efficiency 12%, water consumption 12%, time, rinsing, out of balance load and noise: 22%.
Water use Water use litres 80

Total score

Purchase price in 1997
Graph 1 Water use and 'value' against cost for washing machines. Data from 'Which?' 1997.
However, based on the latest Which? data, the old assumption that more efficient machines cost more no longer seems to stand. This has been confirmed by newspaper advertisements and windowshopping with AA rated washing machines available for less than 200. Whilst the de-coupling of price and efficiency supports our hypothesis, the argument is of little use within the current brief when considering white goods, as there is no inherent over-cost to explain. We will however return to the argument when considering other product groups that have not been subject to market transformation. 4

Total Score 010

With a near saturation of A rated models in the market place the revision of EU energy label is necessary to incentivise consumers to differentiate during purchasing decisions, and to facilitate industry commitments or minimum standards to drive market transformation. Market Transformation Program; Policy Brief, UK energy consumption of washing machines. 19/01/03. This suggests that energy labels have had a very positive influence on machine efficiency. The prominent display of the Energy Efficiency Recommended logo and Energy label rating in adverts indicates that the label matters and is currently used as a positive tool in marketing. Looking forward from say 1995 this outcome was not widely predicted. In the Decade second year report [Boardman et al 1995] the section on Energy Labels and washing machines stated: The EU Energy label for washing machines has been approved by the European Commission. The likely effect of this measure is uncertain as the label lists other information, including wash performance , spin speed and noise. The complexity of the washing machine label may mean that the effect is limited, though retail training may improve effectiveness. Certainly from my own experience as a domestic purchaser of a fridge and washing machine in 1999 and 2000, the sales staff were rather bemused that I should be bothered about the details of the Energy Label. This situation has changed.

A personal observation Whilst I cannot offer a proper historical account or evaluation of the Energy Label, I have been interested to watch it develop. Two presentations from the Greening the Kitchen Conference (1995? hosted by the Environmental Change Unit at Oxford University) stick in my mind. The first was from a representative of UK manufacturers and distributors: he made the point that consumers are not interested in energy savings however worthy they may be. The second was, I think, Dutch and he stated the problem of global warming and the need for action. He then said how manufactures, academics and politicians in his country got together and set targets for energyefficiency. When they reconvened they found that they had exceeded the targets and the resultant goods actually cost less to manufacture and had other benefits. It may be that lessons can be learnt relating to currently floundering proposals to develop a water efficiency label as in Australia.
1.1.1 Appliance exchange programmes, subsidies and vouchers If the purchase of best available technologies is to be encouraged by subsidies then the subsidy has to reflect the required incentive to consider water use rather than the cost to offset an assumed price difference between efficient and inefficient machines. If subsidies are considered for early replacement of inefficient machines then the benefit in terms of water and energy savings is easier to guarantee. However, the cost-effectiveness and environmental cost of scrapping a working machine would have to be examined and quantified. The following two graphs, based on data from the 'Which?' Product Picker web site January 2003, illustrate the issue. Clearly the size of the data set is crucial since it is easy to pick say 5 machines to illustrate a positive, negative or neutral correlation between efficiency and price. Adding some of the
North American top loading washing machines that are now available would provide a definite positive slope suggesting that cheaper machines are more efficient.

Litres/place/cycle

300 Cost 450
Graph 2. Water use per place setting against machine cost for dishwashers.

300 350

Machine

The purpose of this anecdote is to point out that a water and energy consultant who went to considerable trouble, managed to pick the worst performing of the twelve machines that Which? tested in January 2001, because of inaccurate labelling. EU Eco-Label Whilst there seems to be little uptake of the Eco-Label for washing machines or dishwashers in the UK the requirements form a useful benchmark and the committees are addressing many of the issues raised in this report. Water use Energy Washing machine 12 litres/kg 0.17 kW.h/kg Dish Washer 0.625 S1 + 9.25 litres (criteria not found)
Table 1 Eco-Label minimum requirements
These figures translate to 60 litres maximum water use for a 5kg washing machine on a 60C cotton cycle and 16.75 litres per cycle for a 12-place dishwasher. At first glance these figures seem very modest by todays standards for mass-market machines with few exceeding the Eco-Label water or energy usage. The first ad hoc working group meeting for EU Eco-label criteria for washing machines considered revising these figures in September 2002 but decided that reducing the required water consumption could lead to problems of poor rinse performance which is thought to be the limiting factor for reducing water consumption further. Graph 4 appears to support this. The group considered introducing a rinse test but concluded that more work was needed. Exploration of the Eco-Label is incidental to the original brief for this project and so no attempt has been made to follow up on the latest activity. Water Regulations The Water Regulations stipulate a maximum water use of: 27 litres per kilogram load for washing machinesi.e. 135 litres for 5kg 48 litres per kilogram load for washer dryersi.e. 240 litres for 5kg 4.5 litres per place setting for dishwashersi.e. 54 litres for 12 place settings. It is virtually impossible to purchase machines that exceed these maximum water use requirements. Water label? It would be possible to follow the lead of the Energy Saving Trust (EST) and allow manufacturers to add a water efficiency mark for machines using less than an agreed volume. Issues of rinse performance would need to be addressed but the volume testing is already carried out for the Energy Label and issues of verification and trading standards would need to be clarified. The EST energy efficiency recommended label is simply awarded for machines exceeding a certain standard (A) and for water no further differentiation is warranted with current test methods. Candidates for a recommended label might have to use less than 12 l/kg (consensus of eco-label committee) or more controversially say 10 l/kg if rinse performance can be shown to be acceptable for the growing number of machines that exceed this performance. Future ratings could award a + rating for machines with good part load efficiency for example. Other practical issues include the creation of a body to award and administrate such a label.

Old model Efficient model Inefficient model Detergent cost /year Water cost/year Electricity cost/y
Graph 6 Annual running cost of typical washing machines.

/year 2003

120 /year 0

Detergent cost /year

Water cost/year

Electricity cost/y

Old machine

Efficient model

Inefficient model
Graph 7 Annual running cost of typical dishwashers.

purchase

Detergent

Electricity

Water cost
Life Cost (not discounted)
years old machine Efficient budget model Most efficient model
Graph 8 Life cost of 4 washing machines.
1.1.6 Water use trends Washing machines: If the trend continues most machines will soon have an A rating for energy and water use of 60 litres or less (on a 60C cotton cycle for a 5kg load). Of the twelve machines most recently tested by Which? 75% used 50 litres or less per wash and all used less than the 60 litres specified in the EcoLabel criteria, see Graph 9.
100% 90% 80% Percentage of machines 70% 60% 50% 40% 30% 20% 10% 0% Litres per cycle or less
Graph 9. Water use per 5kg cycle for 12 washing machines. Data from Which? Online Product Picker January 2003.
Further efficiencies can be achieved by improved control of water (e.g. for part loads) but this would not show on the current Energy Label. Surveys have shown that 23 kg is an average load rather than the full 5kg which is the typical capacity. A trend towards machines with a larger capacity of 6 or even 8kg could, unless used at full capacity, further reduce part load efficiencies. The greatest potential to reduce running costs and (based on our assumption) environmental impact would be through improvements in detergent formulation and control of dosing to match water hardness, load size and fabric type. Some machines are claimed to control the number of rinse cycles based on foam or turbidity of the rinse water but we have not found any studies to show how detergent dose may then alter water consumption. Again it seems likely that the next direction is in improved control but the current label contains no incentive to achieve this. Dish washers As with washing machines the trend is towards A ratings for energy and low water use. Of the ten machines with a 12 place setting capacity recently tested by Which? all used 20 litres or less and 50% used 16 litres or less, see Graph 10.
Graph 10. Water use per 12 place setting cycle for 10 dishwashers. Data from Which? Online Product Picker January 2003.
1.1.7 Conclusions white goods The performance of new machines is converging with steady elimination of inefficient models. It seems likely that the main driver has been the energy label and the obvious prestige of A ratings. The small variations in water use between current models, regardless of price, effectively prevents any reliable predictions of possible benefit from a subsidy scheme. Other uncertainties include the accuracy of manufacturers claims and real world variations such as part-load efficiency, which is not measured by the current energy label methodology. The drop in price of efficient machines does mean that early replacement of an old machine may be economic depending on local water and sewerage prices and the reliability of the new machine. Not everyone in the white goods industry is convinced of the benefits of energy label driven trend. Some think that wash times and rinsing performance have been compromised to achieve good energy label ratings. The alternative direction is for North American style machines with faster wash times and larger capacity. Whilst these machines are far more efficient than their predecessors they could pose a future obstacle to water saving (by influencing the market as well as direct import). It seems likely that current models have reached the limit of water and energy efficiency as measured by Energy Label test methods with full loads. Real-world improvements could be achieved by improved part-load efficiency and control of detergent dosing or by further education of users to only wash full loads with the minimum amount of detergent appropriate to the level of soiling and water hardness. Detergent costs are the largest running cost for dish and washing machines and are likely to represent a significant life cycle impact, possibly greater than water or energy.

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Average litres per flush

The issue of manufacturing and installation tolerances is not addressed by the regulations and variation above or below the stated flush volumes can be expected. Double flushing If the flush fails to clear the pan then a second flush is required. Whilst this problem has been associated with dual-flush in the UK, it is likely to be become a more regular problem as flush volumes drop. In the US the first wave of 6-litre ultra low flush (ULF) toilets (based on the siphonic pan) often failed to perform as well as the older high flush models and this led to double flushing and even blockage. More recent studies suggest that whilst performance still varies considerably among models, there are now many ULF models that either match or out-perform high flush models. What was found was that the existing test standards were too easily passed and this led to new tests being developed to rank performance, see labelling below. In the worst case a poor efficiency 6-litre WC might be thought to behave as a 12/6 dual-flush with two flushes required to clear solids, including in some cases, single sheets of paper. Discussions with local plumbing merchants suggest that the cheaper 6-litre WCs that they sell (not independently certified) do not flush very well at all. From our own experience in actually carrying out the tests with suites that have been extensively field tested, we are confident that the Water Regulations Performance Specification for WCs (http://www.defra.gov.uk/environment/water/industry/wsregs99/wcspec/index.htm) provides a sufficiently stringent set of tests. A WC suite that just passes these tests should perform significantly better than a WC that just passed the previous British Standard tests. A potentially serious issue is that very few manufacturers seem to be putting forward suites for independent testing and approval and many manufacturers have simply changed the flushing volume of existing WCs that passes the old, less stringent tests at 7.5 litres. Thus we predict that poor performance and double flushing is likely to increase in the short term unless manufacturers are required to achieve the performance standard. We would like to see this hypothesis tested by some random testing of 6-litre suites. User behaviour Some valves and all flappers can be held open by keeping the button or lever pressed. Since cisterns usually retain a volume of water this typically provides a greater flush and is a trick often learnt by users with under-performing WCs. Studies in the US and Canada have reported that some users consider this the normal way to operate a low flush WC. With dual-flush another variable is added. Users may be curious and try both buttons (short term effect whilst novelty wears off?), the operation may be unclear (instructions are required but unsightly) or the user may not want to risk a half flush if there is paper to clear. Where it has been measured, [i.e. the trials listed in the table and Keating and Lawson 2000] trials have shown the ratio of full to partflush to be in the range 1:0 (ie only full flush used) and 1:2 (1 full to 2 part flushes) rather than the often adopted assumptions of 1:3 or 1:4. Refill In the UK (but not the US) WCs are tested for flush volume with the water supply turned off. In practice water enters the cistern during the flush cycle and depending on flush duration and speed of refill this extra volume will vary. The WRc carried out some tests and one result is plotted in Graph 12 (EA Demand Management Bulletin No 30 Aug 98). Portsmouth Water carried out two in-situ measurements of WC flush volume with the water on and off as part of their dual-flush trial and the result is shown in Table 6.

47 years

2 years.

In reality installing 2 WCs would not cost twice as much as installing one.
The two scenarios have a ratio of 23:1 on simple payback due to the compound variables. From a Water Company perspective it is permissible to use average figures as the extremes will cancel. Starting assumptions (provisional as regional data may be available): WC uses per person per day 5 Flush volume of old WC 9 litres Best practice (6/3 or 4.5 single) 4.6 litres actual average flush from evidence Flush volume of standard new 6.2 litres (modest inflow allowance). Household size 2.5 people WCs per household 1.7 [Southern Water personal communication] Cost data (will change quickly) Cost of 4.6-litre equivalent retrofit Over-cost of 4.6-litre from new4 Over-cost of 4.6-litre from newprovisional estimate. 90 (third party certified - price expected to drop) 0 (not third party certified)
It seems reasonable to expect that, for new installations, no over-cost need be attributed to a WC that fits a simple low flush specification (e.g. DEFRA, MTP) as budget WCs are available with 6/4 dualflush cisterns. A higher specification, for example leak free or leak detecting mechanisms, easy maintenance features or delayed action inlet valves may all add cost to a basic specification as could general quality of design and manufacture. Thus, as with white goods, the most important action required would be to ensure that promoted technologies will actually save water whilst encouraging refinements in product designs that will lead to real water savings over the life of the WC. The above assumptions can be used as a basis for estimating an Average Incremental Cost (AIC) for a voucher scheme for a particular water company but the following issues need to be considered: 1. What do we assume for the base case default purchase? With most WC production now claimed to be dual-flush (6/4) it seems unreasonable to assume 6 litres as the default purchase without incentive.
2. What is the real long-term water saving for a low flush WC?
Will valve operated WCs deliver long term savings compared with valve-less models of similar or even higher flush volume? 3. What is the residual life of an existing WC? Given that WCs have a finite life whether due to wear and tear or fashion, it does not seem reasonable to calculate the discounted benefit over the full life of the replacement WC as after, say 5 years, the existing WC may have been due for replacement, already being, say 10 years old. It is estimated that around 140,000 WCs are sold each year for new build whilst about 300,000 are replacements (BRE/MTP Briefing note WC1 Jan 31 2003). It is thought that 50% of domestic WCs are replaced every 16.5 years but it is not known how many of the same WCs are replaced regularly whilst others remain in place for considerably longer.

Both third-party approved, like compared with like. Neither third party approved, like compared with like.
For new installations there are a number of similarities with white goods namely: 1. An over-cost need not be assumed for low water use models in a mature market. 2. If offering vouchers to encourage purchase of low flush WCs what would the default purchase have been? 3. Cost and performance can be de-coupled. 4. There is an issue with self-certification and manufacturer's claims. 5. Real world performance is more complicated than nominal cycle (ie flush) volumes suggest prediction is uncertain. Some differences (in the context of the economics of demand management) are also worth listing for completion: 1. Unlike washing machines, there is often more than one WC per household. 2. White goods have almost universal sizing and are easily replaced (plug and go). 3. WCs may last 2-3 times as long as white goods, fashion permitting. 1.2.11 Replacement programs Where an existing WC is to be replaced then the savings are theoretically greater but the cost is higher and more difficult to evaluate because of installation issues. The much-publicised WC replacement programs in the US are often cited as an example to follow in the UK and it is worth noting some major differences between the two situations. Water and sewerage cost US $1.20/m3 (approx NYC) UK 1.50/m3
Existing WC volumes New Flush volume Existing flush technology Replacement flush tech Existing leakage Standard WC format Metering
18 litres 6 max flapper flapper, drop valve, flapperless (rare) high yes yes
9 litres 6 max siphon valves, siphon very low no 20% approx.
Table 9. Similarities and differences between the UK and US in the context of WC replacement program economics.
1.2.12 Retrofit devices Cistern displacement devices have been studied at length and will not be examined here. Instead we will look at the possibilities for dual-flush retrofit devices, which have been trialled by, among others, Southern Water. These devices are currently illegal but since they have been shown to produce water savings the situation is, at the time of writing, being re-considered by DEFRA. The current legal situation with regards to dual flush retrofit is worth mentioning in passing if only to flag up the fact that it is a mess. A wide range of issues are raised that are beyond the scope of this project: 1. The market is running free of the Regulations. 2. There is widespread confusion as to what is now legal and this changes regularly as new interpretations evolve and leak out. 3. WRAS approval of individual components is used to imply compliance of a whole suite (eg it is implied that a WRAS approved flapper can be legally fitted to an existing WC). 4. Unsubstantiated claims are made about water savings from retrofitting valves to old siphon suites. 27

aggravate moisture problems in bathrooms. A number of trials with instantaneous gas boilers (combi and multipoint) have required a hot basin tap to be left running in order to create enough flow for the boiler to cut in or for the temperature to stabilise!! Such showers may be more appropriate in commercial situations such as sports centres. Our own limited trials suggest that many people are not satisfied with such devices in a domestic setting. A proper trial was beyond the scope of this study but BRE [Pitts et al 2000] and the Norwegian Building Research Institute [Fiskum 1993] have carried out research, which suggests, as might be expected, a positive correlation between flow rate and comfort. It is likely that optimised designs could improve efficiency and limit excess flows without impairing performance but such products are probably not commercially available at present. Thus the most likely route to water efficiency for non-enthusiasts would be to regulate flow rates to an acceptable 'water sufficient' level. For electric showers, no intervention is required as flow is limited by power input. For gravity showers, appropriate choice of shower head and the use of restrictors could help and for pumped and mains pressure showers, dynamic flow regulators can be used. These measures simply limit maximum flows without improving efficiency and the devices can easily be removed. Thus the main function is to limit the user's freedom to increase the flow rate higher than the 'owner' has set. Multi spray panels can deliver very high flow rates but have previously been limited to the luxury market. A recent trend is for low-cost multi-head showers with up to 8 showerheads. Figure 13 shows a range of 'water saver' showerheads. From left, three air-entraining models designed to work at about 10 l/min, two atomising heads that work well at 6 l/min and a flow regulator for use with showers.
Figure 11 Some water saver showerheads for use at mains pressure.
Figure 12. An atomising showerhead in use.
Figure 13 Standard showerhead at mains pressure but regulated to 6 l/min.
1.3.5 Other factors The ergonomics of temperature and flow controls, dead legs and other factors will also influence total water use (see EA water saving fact cards). Even factors such as cubicle design will have an influence as a sealed and well detailed cubicle or wet room will allow far higher flow rates than say a fabric shower curtain over the bath, without causing water damage. 1.3.6 Water use compared with baths It is well known and easily proven (take a shower in a bath with the plug in) that showers can use much less water than baths. However: showers tends to be taken more frequently than baths. water use depends on the time spent in the shower. high flow rate 'power showers' (>12 l/minute) may use as much or more water than a bath, limited only by the capacity of the hot water system. The trend is towards higher flows so a new shower is likely to be of higher flow than older low power electric models or restricted gravity fed designs. Thus the currently available public domain data on water-use due to showering is unlikely to be appropriate when predicting future water use due to increased showering. 33

1.4 Direct Hot water systems an initial review
1.4.1 Introduction Combination boilers account for over 50% of the domestic boiler market and this is predicted to rise. Whilst 'combis' offer a number of advantages over conventional boiler and cylinder arrangements, the issue of water wastage has been the subject of concern in demand management circles for some time [e.g. Howarth 1995]. The problem is that when starting from cold, it can take a long time for hot water to reach the tap. After the tap is turned on, a pressure sensor tells the boiler to fire in hot water mode. The boiler then goes through a purge cycle and fires. The primary water circuit then heats up and this then heats the secondary (mains) water to the tap. All this can take over a minute which is frustrating and a waste of water and energy. The actual volume of water wasted depends on patterns of usage, user requirements (warm or hot required) household size and heating season. No robust figures are known. If the issue of warm-up losses can be addressed then combi boilers or a combi-storage hybrid could actually offer water savings by reducing dead-legs if installed with smaller pipes made possible by the mains pressure e.g. 8 or 10mm to kitchen tap. 1.4.2 Solutions A number of solutions are used. Some boilers leave the fan running which saves a few seconds by avoiding the purge cycle but electricity is wasted, fan life is reduced, the constant noise can be irritating and warm up is still required. Others keep the heat exchanger warm. This 'keep warm facility' wastes energy and the heat exchanger is not usually insulated. Sometimes this facility can be turned off or controlled by a timer. The third solution us to use a small hot water store in the primary (boiler water) or secondary (mains water) water circuit. This is usually insulated so heat loss should be low but this figure is rarely, if ever, reported in the SEDBUK database (Seasonal Efficiency of Domestic Boilers in the UK. www.sedbuk.com). SAP 2001 includes definitions of the various boiler types and equations for the seasonal efficiency of instantaneous and storage combination boilers. The equations are unlikely to be accurate for smaller thermal stores where significant heatloss will be along pipes and other connections. The SAP/SEDBUK equations estimate efficiency loss (i.e. a percentage to be subtracted from the measured boiler efficiency) as a function of volume and insulation thickness. These assumptions may be reasonable for larger stores (>150 litres say) but are likely to give incorrect values for smaller (say 20 litre) stores. 1.4.3 Associated issues Whilst we are primarily considering water use, a more important environmental and economic consideration for boilers is energy use. Because of the possibilities for a potential trade off between water saving and energy efficiency (eg keep warm facility) any attempts to influence policy (Building Regulations, Water Regulations, MTP etc) to promote water efficiency must be integrated with energy considerations. An ideal design should save both water and energy. 1.4.4 Drivers Whilst users may perceive a 'benefit' from 'inefficient' showers, the water wastage due to combi warm up is simply a nuisance, which might reasonably disappear due to market pressure. The main environmental concern is that any energy cost to achieve this, which might not be accurately reflected in the SEDBUK and SAP ratings. With a realistic assessment of this energy cost/benefit, manufacturers would be encouraged to design out inefficiency. 36

Table 16 showing assumptions for graph below. 4.6-litre WC installed instead of 6-litre.
250 PV sum of saving scenario A, 2.5 person house 200 NPV of saving PV sum of saving scenario B, 4 person house.
Graph 18. Discounted NPV of saving when installing a 4.6-litre effective flush in place of a 6-litre flush WC.
2.3.3 Option 3 appliance replacement As with white goods, whilst the cost of replacing an existing working appliance is greater than for new installations, the savings are potentially greater. Again there will be considerable variation between households. Graph 19 shows the discounted NPV of savings against time when a 9 litre WC is replaced by one with a 4.6 litre effective flush (e.g. 6/3 dual flush). The installation cost is assumed to be 200 and all other assumptions are as before, i.e. 1.50/m3 water and sewerage charges, 5 WC uses/person.day and 6% discount rate.
400 PV sum of saving 2.5 person house NPV of saving 1 -100 -200 -21 Year PV sum of saving 4 person house
Graph 19. 9 litre WC replaced with 4.6 litre WC.
A similar exercise can be carried out as for washing machine replacement, where 10 or 20 year life costs are plotted with the 'do nothing scenario' including natural WC replacement. Thus a future replacement cost is borne now in exchange for reduced water bills. A more complex model is required if averages are to be calculated based on assumption about the current age distribution of installed WCs flush volumes and life span.

2.4 Showers

Since shower water use depends on even more variables and uncertainties than the other areas examined no attempt will be made at an economic evaluation between the numerous possible scenarios. Instead we will use the example of a 10.8kW electric shower replacing a bath but acknowledge that the usage assumptions are not robust. Bath 80 litres 0.34 [EA 2001]. 30 C t by gas 75% 3.48 kW.h9 0.19 0.66 for heating only 2p 1.5/m3 9.9m3 9.9 (9.9 x 1 kW.h/m3) 14.85 8.64 91.8 kg 23.49 Electric Shower 6 l/min x 6 minutes = 36 litres 0.6 [EA 2001] 10.8 kW electric 100% 1.08 kW.h10 0.41 0.44 for heating only. 7p 7.88 7.88 11.83 16.56 104.24 kg 28.39
Volume per use Uses/person.day Heating Efficiency KW.h Kg CO2/kW.h Kg CO2/bathing Energy cost/kW.h Water & sewerage cost1.5/m3 Water/person.year Kg CO2 (water) Water cost/p.y Energy cost/p.y Kg CO2/p.y Total cost

The average replacement period for long life products such as WCs is less than the average product lifespan because of fashion and refurbishment. Water saving Where possible trial data should be used rather than assumptions based on theoretical reductions. Until savings can be measured on a large sample under non-trial conditions, even trial data must be treated with caution. Some of the problems with predicting water savings are outlined in the product review section.

3.4 Sensitivity and risk

Some values such as discount rate and variable opex may vary over time and between regions but can be agreed and will be common to all options being considered. Other variables such as installation period and cost of measures must be estimated for the purposes of hypothetical examples as presented here but can be tied down for a specific project. The third category of variables are currently less certain either due to lack of reliable data or dependence on other factors such as untried technologies, rebound effects, price elasticity, social and economic trends etc. This category includes figures for water savings and life of options. Thus it is recommended that a risk analysis be carried out to estimate the likelihood of savings for a range of scenarios. Obviously this is complicated by more than one uncertain variable. Table 18 illustrates a range of options based on the following common assumptions:
Variable Discount rate Variable opex WC flushes/person.day WCs per household Occupancy Time period NPV Av'ge flush for existing WCs Best practice WC Old washing machine Default new washing m/c Best practice new washing m/c Washes/week Source 3.5% Treasury 6p/m3 Estimate discussed above 5 Widely agreed figure 1.7 Southern Water (SW) (34,000 sample) 2.5 SW, average. Metered (2) and un-metered (2.6) 30 years 9-litres 4.6 litres/flush average (e.g. 6/3 dual, 4.5 single) 100 litres/cycle, 5 years residual life 60 litres [1] 50 litres [1] 7
Notes on assumptions [1] see product review section which suggests that default purchase could have lowest water use. The figure here is to illustrate saving if a difference of 5-10 litres per cycle can be identified for example by a refined energy label.

From scenario

Installation period yrs.

Considering the bracketed values of 20 year life, 20 voucher cost and 9.4 litres/day water saving we get an AIC of 34p at 3.5% discount rate and 42p with a 6% discount rate. Scenario 3 This scenario is based on the WC replacement schemes in the US. The installation cost would depend on many factors and it is possible that the customer could contribute. Issues of performance, leakage, and compatibility as discussed in the product review must be considered. The WC price is a guess based on 1.7 WCs per household. An alternative scenario would be to provide a voucher towards the cost of a new WC and this could be set at value that balances cost and rate of uptake but again some practical issues need to be resolved. Scenario 4 Here we look at an appliance exchange program for older washing machines assumed to use an average of 100 litres per wash and with a residual life of 36 years. The replacement machine is assumed to use 50 litres/wash. Particularly because of the short residual life of the old machine (it would be due for replacement anyway) the economics are not particularly good. Many consumers might jump at the chance of a new efficient machine given the incentive of a voucher but the uncertainties about default purchase and the problems of administration probably rule out this option even before we consider life cycle issues. Scenario 5 As with scenario 2, this option would require a reliable method of differentiating between the performance of available products. In order to calculate the AIC, an assumption has to be made about default purchase behaviour. If a differentiation can be made then an incentive scheme (vouchers, discounts, bulk purchase of efficient machines etc) should drive the market towards more efficient machines for purely commercial reasons. Hence even an apparently uneconomic scenario could contribute to market transformation on a wide scale. The same argument applies to other products. Scenario 6 Showering presents different problems for economic prediction as the trend is for increased use and higher flows. Insufficient data was available for us to make meaningful AIC calculations so the figures in the table should only be taken as an example.

CONCLUSIONS

This study set out to calculate the cost benefit of a number of domestic demand management measures from the perspective of householders and water companies. In the event, more questions have been raised than answered but a number of interesting and unexpected results have emerged. 1. When water efficiency is addressed at point of manufacture, this can be achieved with little or no over-cost. However, replacing or upgrading existing fittings will always incur an additional capital cost. 2. For all the original scepticism, the Energy Label does appear to have been successful in transforming the white goods market towards higher energy, and as a by-product, water efficiency. Not surprisingly, manufacturers are likely to design products to meet the label requirements and are unlikely to include features that do not earn credits or avoid penalties. It seems likely that white goods are approaching the limit of efficiency in terms of the measured parameters, but differentiation could still be measured and progress encouraged by refinement of the label. Whilst an evaluation of labelling was only incidental to this study, a number of issues have been raised that could inform the ongoing debate about a possible water efficiency label scheme. 3. From the householder's perspective the running costs of appliances are unlikely to feature heavily on a buyer's list of priorities. Water Companies can take a longer-term view and compare demand-side measures with resource development. As expected, dual-flush retrofit stood out from the crowd, being a relatively low cost measure with proven savings. Potentially greater savings could theoretically be achieved by replacing older 9-litre WCs with the most efficient models now available but the cost is higher and there are a number of risks relating to actual water saving and long-term reliability of valve mechanisms. 4. A major variable that has been highlighted when considering retrofit and product replacement programs is the life of the measure, which is used to calculate the AIC. Typically this has been the expected life of the new product but with the market moving towards water-efficiency (in terms of measured parameters) it is more reasonable to use the residual life of the old product that is being replaced. This may be a suspect prediction as products are changed because of fashion and economic trends rather than at the end of their natural life. 5. Any scheme that is to promote efficient goods, requires a best practice performance specification and a way of differentiating between products. The study shows that the accuracy of the Energy Label has been found to be questionable and that a number of real-world variables might lead to performance differences between apparently identical products. Examples include part-load efficiency of washing machines and dishwashers or the actual flush volume of WCs when connected to a water supply. A related issue is the equivalent effective flush of dual-flush WCs when compared to single flush. Currently programs such as the proposed Enhanced Capital Allowance Scheme use ratios of full to half flush based on human metabolism rather than field data of user behaviour. 6. Once 'better products' can be identified and differentiated then there is considerable potential to encourage the market to move in the right direction. Voucher and discount schemes to encourage the purchase of the most efficient technologies are likely to have an impact beyond calculated AIC benefits as manufacturers not meeting such standards would be at an economic disadvantage. 7. Whilst most product groups seem to be heading towards water efficiency, water use for personal bathing is increasing. More research is needed to identify trends and potential savings. Because of the wide range of installed technologies we have effectively dismissed 'water saver' shower head retrofits in the context of this study but would push for consideration of labelling and regulations for mains pressure and pumped showers as has happened in the US and is being considered in Australia. Whilst not considered in this study, we believe that bath sizes are also increasing. Improvements in hot water systems mean that for many modern households, virtually unlimited hot water is available on demand. 49