Int. J. Sustainable Design, Vol. 1, No. 1, 2008
Lightbulbs and nappies: sustainable development
and customer perceptions
Tim Short*
Department of Engineering,
The University of Liverpool,
Brownlow Hill, Liverpool L69 3GH, UK
E-mail: [email protected]
*Corresponding author
Joan Harvey
School of Biology and Psychology,
Division of Psychology, Newcastle University,
Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
E-mail: [email protected]
Abstract: Recent interest in ‘green’ versions of everyday objects has led to a
market presence for energy-efficient lightbulbs and the re-emergence of
reusable nappies (diapers). Given their ease of use, one might think that ‘green’
lightbulbs would become far more popular than reusable nappies and the
associated inconvenience. However, this is not always the case. The paper takes
a novel approach to understanding consumers’ behaviour, using functional
analysis to examine ‘green’ and ‘normal’ products and demonstrating why
some refuse to use energy-efficient lightbulbs, despite using reusable nappies.
It considers how consumer perceptions have developed and the implications for
engineering designers.
Keywords: sustainable development; product design; engineering design;
consumer psychology; functional analysis; objectives tree; voice of the
customer.
Reference to this paper should be made as follows: Short, T. and Harvey, J.
(2008) ‘Lightbulbs and nappies: sustainable development and customer
perceptions’, Int. J. Sustainable Design, Vol. 1, No. 1, pp.13–28.
Biographical notes: Tim Short, Chartered Engineer and Senior Lecturer
in Engineering Design, is currently researching Design for Sustainable
Development, theory and practice. His research builds on the Brundtland
definition of Sustainable Development, considering design methodologies to
meet the needs both of today and of the future. His research therefore
recognises the requirements of today: in the UK this is particularly represented
by the need of industry to sustain itself; in developing countries the focus is
more on the Millennium Development Goals, including water and sanitation.
For such requirements to be fulfilled sustainably, their impact on the future
must be considered.
Joan Harvey, Chartered Psychologist and Senior Lecturer in Applied
Psychology at Newcastle University, is currently researching consumer
attitudes and perceptions of various product groups and health risks,
Copyright © 2008 Inderscience Enterprises Ltd.
13
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T. Short and J. Harvey
and has a particular focus upon attitudes, beliefs and perceptions of energy,
recycling, waste and sustainability. She has extensive work/consultancy
experience and is a British Psychological Society & Newcastle University
spokesman for psychology, with many TV, radio and newspaper appearances.
She is a member of the Technical Programme Committees for PSAM 2008,
and was similarly for ESREL 2006 and 2007, responsible for risk perception
and communications.
1
Introduction
The typical consumer faces a number of different pressures when choosing which product
or brand to buy. There is a plethora of brands, each making competing claims, using both
cognitive and affective appeals. Equally, however, the product designer is faced with
competing pressures – some corporate, some legislative, some simply to do with making
a product ‘commercial’. One of the pressures for both consumer and designer is the
desire to be ‘green’, to have a product that can be seen to be ‘environmentally friendly’
or ‘sustainable’. Unfortunately, consumers face a barrage of information as to what
is or is not sustainable, whilst designers believe that green implies expense and
non-competitiveness. Despite these problems, some products have appeared on the
market and are trying to succeed based on, amongst others, their green credentials.
In this paper, two products are considered – the lightbulb and the nappy (or diaper).
The standard (incandescent) lightbulb has changed little since the early twentieth century.
Recently, however, energy efficient lightbulbs (or ‘green lightbulbs’ – where ‘green’
refers to their environmental/sustainability credentials rather than their colour) have
entered the market, playing on reduced life-time costs (despite high initial costs) and
increased ‘green-ness’ for marketing ploys. To some extent, these lead consumers to feel
guilty should they not purchase such a green product. The disposable nappy, on the other
hand, appeared in the mid 20th century and was seen to be a boon to the household,
removing the need for continual washing of a particularly unpleasant item! Recent
concern has highlighted the volume of landfill taken up by nappies (Leicestershire
County Council, 2006), such that the reusable, washable, green nappy is becoming more
widespread, despite its obvious problems.
Figures 1 and 2 show examples of lightbulbs and nappies, respectively, with both
normal and green products shown next to each other. Those shown are typical examples,
bought locally.
Figure 1
Green candle bulb (left) and normal candle bulb
Lightbulbs and nappies: sustainable development and customer perceptions
Figure 2
15
Disposable nappy (lower left) and green (re-usable) nappy with cotton insert (top)
The lightbulbs in Figure 1 are both candle-style bulbs with standard bayonet fittings and
similar intended power ratings – 7 W for the green bulb, 40 W for the normal bulb.
In many (although not all) cases, this style is designed to be seen, with no lampshade to
be used. The difference in size between the green bulb and the normal bulbs is clear and
is typical of bulbs in general, not just candle bulbs.
The two nappies in Figure 2 are both aimed at a similar age/weight of baby, around
ten months old. The normal nappy on the lower left is designed to prevent the leak of
faeces and is single use, with a flexible waist band, Velcro-style fasteners on the waist
band, and an absorbent core to capture and store urine. The green nappy on the right has
three components: a washable outer with flexible waist band and Velcro fasteners on the
waist band; a folded cotton inner which is placed inside the outer, to capture and store
urine; and a one-way, biodegradable, flushable membrane to prevent fluid remaining in
contact with the baby’s skin. It is also designed to prevent the leak of faeces and has
similar dimensions to the normal nappy, as can be seen, but is slightly bulkier in use,
because of the cotton inner. On the other hand, once wet, the super-absorbent disposable
nappy swells to many times its original size.
2
Product purchase
Before considering the products in further detail, it must first be understood why people
actually buy products. Weightman and McDonagh state:
“Individuals purchase and consume products for a variety of reasons … In most
cases in Northern countries, these purchases involve people buying
replacements for existing products. This may be due to product failure, or the
need for uneconomic repairs to existing products. Sometimes it will be to
achieve improved functionality, where the existing product has become
obsolete or obsolescent, or where the new product performs significantly better
… Of course, the reason can also be improved supra-functionality, as products
are replaced with ones that look better, have different symbolic associations,
are from more highly regarded brands, or are just cooler.” (Weightman and
McDonagh, 2004, p.93)
After deciding to replace a product, therefore, the decision on exactly what to purchase
involves a number of trade-offs, such as price-value, price-convenience, price-reliability,
16
T. Short and J. Harvey
longevity-aesthetics and many more in various combinations, each of which has different
implications for consumers. These trade-offs are complicated by the consumer
being bombarded by information and may suffer distortion from reality due to many
perceptual influences and biases. According to Statt (1997), research indicates that half of
US consumers say they are willing to change their buying or consumption patterns to take
account of environmental concerns, but the willingness and actual behaviour are two
different things, perhaps because economics can override good intentions. Statt also
suggests that there are limits to the average consumer’s green behaviour, for example in
terms of driving greener cars, or even giving up cars. So decisions about what to replace
a product by are complex, involving trade offs, willingness to pay, economics, as well as
functionality, aesthetics and comfort.
Firstly, considering nappies: when children are young, nappies are an essential,
frequently used product, of a low-involvement routine nature, according to the
classification of products by Richins and Bloch (1986). However, it could be argued that
advertisers, especially in the UK, are trying to raise the disposable nappy into being
a high-involvement product by drawing attention to the affective rather than the cognitive
issues, such as emphasising softness and flexibility of the product and by implying that
‘superior’ parents use certain named products. In addition, getting impartial information
about costs and environmental issues is not easy, as most sources may appear to have
vested interests. Examples of this include claims such as “ ... a cloth nappy system will
cost you approximately £400 from birth to potty. That’s a saving of up to £800!!! ....”
(Jewson, 2006), and the debate about water consumption in cleaning reusable nappies.
Much of the information, however, is only partial, resulting in dissonance that most
people resolve by disregarding the information altogether and making the decision based
on convenience which, in time-poor families, outweighs the cost side in the trade-off
insofar as it could be calculated (Festinger, 1957; Harvey, 2005). In terms of the analytic
framework provided by Samuelson and Biek (1991), comfort and health, low effort and
probably perceived low legitimacy of the problem all combine to reinforce the decision to
buy disposable nappies.
In the case of lightbulbs, there are issues of cost and value, convenience and
functionality, and any trade-offs operate differently compared to nappies. Light bulbs
constitute a low-frequency purchase, low involvement, rational and routine product
which is a necessity. There is little or no advertising, and no apparent move by marketers
to shift the product into a higher involvement category. The trade-offs are simple
and rational: initial cost versus reduced running costs and convenience of fewer
replacements, plus any other issues of ease of purchase and perceived performance
quality (e.g., brightness of light) and green considerations. Again, the analytic framework
of Samuelson and Biek (1991) can help: comfort and health are hardly relevant,
the situation is relatively low effort/low payoff, the role of the individual consumer has
not been emphasised as important (relative to other issues) and whilst the legitimacy of
the problem may be recognised, there is the fear (a perception of risk issue, (Statt, 1997))
that the product may fail quickly and therefore reduce its cost saving.
The ‘green’ consumer adds a further dimension beyond the normal situation and has
therefore been considered in detail. According to Harvey
“Attitudes may … be influenced by demographics, lifestyle, self identity and
social status, all of which help set the frame in which perception of ‘green’
consumer behaviour must be considered.” (Harvey, 2005)
Lightbulbs and nappies: sustainable development and customer perceptions
17
Whilst Harvey quotes Zimmer et al. (1994) as suggesting that “beliefs in green issues
(may) reflect a form of responsible citizenship”, she also notes that “altruism alone may
not be sufficient to persuade the greater majority to act in sustainable ways as good
citizens”. Indeed, Joyce et al. (2004) show that only 20% of consumers perceive
themselves to be ‘green’ in terms of proactive recycling – an issue close to green
consumerism. This is extended into a 20 : 60 : 20 model for consumers: the green 20%
are likely to allow some compensation in the trade-off by including their feel-good or
normative/moral to offset either lower quality and/or higher prices; 60% of consumers are
complacent and are most likely to wait for some action by manufacturers or suppliers or
by government rather than engage in some consideration of trade-offs of any kind;
the remaining 20% display a negative attitude towards green products. The latter two
groups, comprising 80%, may well take no action in any green direction unless they have
little or no choice but to do so; for example, reduced or ceased supplies of non-green
products or increased taxation; much better promotion of green products, when
accompanied by reduced or no promotion of comparable non-green ones might also have
an effect. Khosla et al. (2005), using a model which gauges consumers’ intention to
purchase green products, suggest that in comparison to non-green products, consumers
of green products are more strongly resistant to lower quality than to higher prices.
However, this finding may apply differentially. It should be noted that the ‘quality’ of a
product in this context includes the product’s functionality in addition to superior style,
aesthetics and comfort.
Harvey (2005) notes that “if we feel that we are carrying an unfair share of the burden
of costs … then we may act or change our beliefs in order to restore equity”. Included
within these costs are finance, time and societal. It could equally be suggested, however,
that ‘lack of function’ is a cost – if a green product does not share the same functionality
as a normal product, the purchase of the green product implies an “unfair share of the
burden of costs” on the consumer – other consumers benefit from the improved
functionality so why shouldn’t this consumer?
Referring back to the quote from Weightman and McDonagh, it is clear that the
functionality of the product is crucial, either directly, or as part of a trade-off decision.
Provision of the right functions will often only allow the product to be an ‘order
qualifier’, rather than an ‘order winner’ (Hill, 1999); on the other hand, failure to
deliver this functionality will mean that the product will not be considered. A proper
understanding of the functionality of a product is crucial if it is to be successful in the
market place, and this will therefore now be considered in more detail.
3
Analysis
The starting point of an engineering analysis of the two products is a consideration of
their key functions. For the lightbulb, the ‘top level’ function is the provision of light.
The nappy, on the other hand, can be considered to contain bodily waste. This, however,
is not sufficient and further analysis must now take place.
‘Functional Analysis’ (sometimes also known as ‘function analysis’, ‘function trees’
and so on) is a standard engineering design tool (Pugh, 1990), used to ascertain the basic
underlying functions that a product must perform, without saying anything about the
method the product should use to perform the functions. The output of the analysis – the
Function Tree – says what a product must do without saying how it will be achieved.
18
T. Short and J. Harvey
The analysis may be carried out early on in the new product design process, to begin to
turn a User Requirement Specification (URS) into an engineering product. Alternatively,
it may be used in the re-design of an old product, to stimulate the search for new
solutions by removing preconceptions of the old solution. For example, in considering the
redesign of a vacuum cleaner, a designer may well suggest a basic function of “suck dust
into bag through a filter” – this defines how the product is to achieve the goal (‘suck’,
‘into container’, ‘via filter’) which removes the potential for creative solutions.
If the basic function is, instead, assumed to be ‘get dust into container’, any number of
alternatives may be considered, one of which would be the ‘Dyson’ vacuum cleaner
which revolutionised the market place.
Functional analysis is, therefore, an extremely useful tool for the engineering
designer. Even so, it is a tool missing from many designers’ tool boxes. The usefulness of
the tool will now be demonstrated in the context of this paper – lightbulbs and nappies.
The primary function (or ‘first level function’) of the light bulb could be assumed to be
‘provide light’. At first glance this may seem to be the only function of the product;
however further examination suggests a number of ‘second level’ functions beneath the
primary function – such as ‘provide fixing’, ‘be cheap’ and so on (Figure 3).
Figure 3
Basic function tree for light bulb
The analysis can be continued by adding more detailed third level functions, as in
Figure 4. The third level functions now begin to tell the consumer something about the
product. In this case, specifics can be added such as the absolute size, the spectrum of the
light that will be produced, how bright the light will be and how long it will take, from
the flick of the switch, for light to be provided. Interestingly, all of these are defined by
tradition – by what the market expects from a light bulb. This proves to be crucial in
evaluating performance, as will be seen later in the paper.
Figure 4
Extended function tree for light bulb
Lightbulbs and nappies: sustainable development and customer perceptions
19
Whilst this may be an accurate means for considering an incandescent light bulb, it is
clearly not appropriate for an ‘environmentally friendly’ lightbulb. Figure 5 therefore
shows the equivalent tree for a ‘green’ light bulb.
Figure 5
Function tree for green lightbulb
There are now two added second level functions: ‘Last long’ and ‘Use low energy’,
noting that the low energy is in both manufacture and in life. Similar trees are shown in
Figures 6 and 7 for disposable and re-usable nappies. It is clear that in each case, the tree
represents the subjective opinion of the authors as to what specific functions should be
achieved. Objectivity would normally be achieved by taking the combined opinions of
members of the design team, including input from the marketing representative, for
example. Whilst the trees shown in this paper are prepared by the authors, they have been
tested on a class of 30+ students and were roughly agreed upon within the class.
Figure 6
Function tree for disposable nappy
Figure 7
Function tree for green reusable nappy
20
T. Short and J. Harvey
For both the lightbulb and the nappy it can be seen that the green function tree is very
similar to that of the normal function tree; the green solution is expected to provide
all the functions of a normal product, but with a few additional functions relating to its
‘green-ness’. Thus, designing a green product is more onerous than designing a standard
product.
4
Evaluation
In order to differentiate between design solutions, some means of evaluating the solutions
is necessary. Given the structure of the function tree, the use of an objectives tree,
as described by Pahl and Beitz (1995) would seem a relevant approach. In this
methodology, each function is given a weighting as to how important it is, relative to the
other functions. Sub-functions (such as ‘cleanable’ and ‘biodegradable’ in Figure 7) are
also weighted, as part of the over-riding function. Whilst the output of this analysis can
easily be represented as a tree in the same manner as the functional analysis, slightly
easier for presentation in this paper is the use of a table as in Table 1.
Table 1
Weighting factors for green lightbulb functional analysis
1st level
2nd level
Weighting
Provide light
Provide fixing
0.3
Look right
0.3
Be cheap
0.1
Last long
0.15
Use low energy
0.15
3rd level
Weighting
Size
0.1
Colour
0.05
Shape
0.05
Brightness
0.05
Speed
0.05
Manufacture
0.05
Life
0.1
In this analysis, the sum of all the second level weightings is 1, and weightings
for each third level function are calculated to add to the total weighting of the
relevant second level function. The logic used to provide these weightings is to apply the
question “without this function, would the customer buy the product?”. Thus, if the
fixing was not provided, or the fixing was not correct, the customer would not buy
the product; the function is, therefore, given a high weighting factor. Again,
the weightings are subjective, with some level of objectivity only when they are provided
by a design team. Similar weightings can be seen in Table 2 for the green nappy
functional analysis.
To provide the evaluation of each solution against these criteria, an assessment is
made as to how well the solution meets the criteria. This can be done as a simple binary
“does the solution meet the criteria? – yes or no”; if the answer is ‘yes’, the value of the
weighting is used, if ‘no’, a value of 0 is given. The sum of all these values will then give
a score out of 1 for that particular solution. An alternative is to use the German guideline
Lightbulbs and nappies: sustainable development and customer perceptions
21
VDI 2225 (1997); here, a mark out of 4 is given as to how well the solutions meet each
function, according to the descriptors in Table 3.
Table 2
Weighting factors for green nappy functional analysis
1st level
2nd level
Contain
waste
Remove waste
0.3
Be convenient
0.2
Table 3
Mark
Weighting
Be cheap
0.15
Be reusable
0.2
Use low energy
0.15
3rd level
Fixing
Weighting
0.08
On/Off
0.08
Disposal
0.04
Cleanable
0.1
Biodegradable
0.1
Manufacture
0.05
Cleaning
0.1
Evaluation according to VDI2225
Equivalent descriptor
0
Unsatisfactory
1
Just tolerable
2
Adequate
3
Good
4
Ideal solution
Source: Adapted from Pahl and Beitz (1995)
For example, consider the cost of a lightbulb, with a weighting of 0.1; the normal
lightbulb might be thought of as being ‘good’ against this function, thus receives a mark
of 0.1 (weighting) multiplied by 3 (mark for ‘good’) = 0.3. This is carried out for all
functions and a total mark out of 4 is thereby achieved for each solution provided.
Table 4 shows the results for evaluating a normal and a green bulb against the green bulb
weighting criteria. For example, both bulbs are given 4/4 for providing a fixing, but
whereas the normal bulb is given 4/4 in all criteria under ‘look right’ (as this is the
standard, the tradition, against which all bulbs are measured), the green bulb scores
poorly.
A justification for each of the scores above is provided in the appendix, but is
unnecessary for the continued analysis. Table 5 shows the equivalent evaluation of the
nappies. Again, justification of these scores is provided in the Appendix.
It is interesting to note the main points of contribution to the total weightings for both
the lightbulbs and the nappies in Tables 4 and 5. The normal lightbulb scores better on
looks and price, losing out heavily on the use of low energy; the normal nappy fares
better on price and convenience but loses on reusability and energy. In both cases, there
are differences centred on price and energy; therefore if the price issue can be resolved,
the relative advantages and disadvantages are altered. For lightbulbs especially, the price
issue may be reinterpreted and this is considered in the discussion.
22
T. Short and J. Harvey
Table 4
Evaluation of normal and green lightbulbs against green weighting criteria
Normal bulb
1st level
2nd level
Weighting
Provide
light
Provide
fixing
0.3
Look
right
0.3
Be cheap
0.1
Last long
0.15
Use low
energy
0.15
3rd level
Weighting
/4
Total
/4
Total
4
1.2
4
1.2
Size
0.1
4
0.4
1
0.1
Colour
0.05
4
0.2
2
0.1
Shape
0.05
4
0.2
1
0.05
Brightness
0.05
4
0.2
2
0.1
Speed
0.05
4
0.2
1
0.05
3
0.3
0
0
0
0
3
0.45
Manufacture
0.05
2
0.1
1
0.05
Life
0.1
0
0
3
0.3
Total
Table 5
Green bulb
2.80
2.40
Evaluation of normal and green nappies against green weighting criteria
Normal nappy Green nappy
1st level 2nd level
Contain Remove waste
waste
Be convenient
Weighting 3rd level
Weighting
/4
3
0.9
3
0.9
0.08
4
0.32
3
0.24
0.3
0.2
Be cheap
0.15
Be reusable
0.2
Use low
energy
0.15
Fixing
/4
Total
On/Off
0.08
4
0.32
4
0.32
Disposal
0.04
3
0.12
2
0.08
3
0.45
2
0.3
Cleanable
0.1
0
0
4
0.4
Biodegradable
0.1
0
0
4
0.4
Manufacture
0.05
1
0.05
3
0.15
0.1
0
0
2
0.2
Cleaning
Total
5
Total
2.16
2.99
Discussion
Before considering the numerical results, it should be recognised that, whilst the authors’
scoring of the products is subjective, a measure of objectivity is added from more
independent results. A number of students carried out an identical analysis as part of their
final year undergraduate engineering exams. Contrary to the authors’ expectations the
students all produced similar results to those above and, thus, it can be suggested that
the results presented are fair.
Returning to the results of the analysis, these can be seen in the total score for each
product. The lightbulbs score 2.80 and 2.40 for normal and green bulbs, respectively,
whilst the nappies score 2.16 and 2.99 for disposable and green versions, respectively.
Lightbulbs and nappies: sustainable development and customer perceptions
23
Bearing in mind the prevalence of the energy efficient lightbulb in comparison to the
re-usable nappy and the latter’s high capital cost, it might be expected that green
lightbulbs would perform better than green nappies.
The results reflect each product’s functionality: if a product is to score highly in this
analysis, it must carry out the required functions. The reusable nappy carries out all its
functions in a similar manner to a disposable nappy, but also benefits from green
functions beyond those of the disposable. The green bulb, on the other hand, fails to
match the functionality of the normal bulb and, therefore, fails to be even an ‘order
qualifier’, let alone a ‘winner’.
Despite this analysis, Harvey et al. (2003) show a relatively high take up of green
lightbulbs – in Harvey’s case around 56%, although this may well be skewed by the high
percentage of students in the sample. It is not expected that 56% of parents use reusable
nappies, so why does such a difference exist?
The fact that these findings appear counterintuitive is potentially explained by
consumers’ perception of price and cheapness in relation to their perception of time.
The traditional life-cycle model assumes that people work out an optimum consumption
plan and then stick to it as far as possible (Furnham and Argyle, 1998). There is now
considerable evidence, however, that delayed gratification, such as saving money through
lower in-use energy consumption, causes many people great difficulty (Furnham and
Argyle, 1998). Liebermann and Ungar (2002) suggest that many decisions made by
consumers are intertemporal and that life-cycle costs represent a specific type of this,
involving two components: a present purchase price and future maintenance costs.
Thus, when green lightbulbs cost up to seven times the price of normal lightbulbs
but last more than ten times longer and running costs are substantially reduced,
it would seem rational to use green lightbulbs. However, the time horizon is relatively
undefined – people may be able to count in years when they last bought white goods such
as a washing machine, but when did they last buy a lightbulb? This, combined with the
large multiplier in purchase price, mitigates the choice to buy green. The case for nappies
is slightly different in that at every nappy change, the customer sees one less disposable
nappy and therefore an immediate financial saving – an in-use saving that is not as
apparent with green lightbulbs.
The consideration of the functionality of the bulbs therefore clarifies some of the
reasoning for a consumer’s choice not to buy green lightbulbs, in showing green light
bulbs as not cheap. For the 20% of consumers who define themselves as ‘green’, green
lightbulbs are, in fact, cheap when costs are distributed over the life-time of the bulb.
Whilst this is accounted for in the function tree as ‘use low energy’, it perhaps goes
beyond this for the consumer, and affects perception of the capital cost as well.
In essence, the total score for green lightbulbs is superior if the cheapness score reflects
that for the green consumer, and the scores hinge on how cheapness is defined in rational
(total cost) or affective (purchase cost) terms. For people who find changing lightbulbs to
be a particular problem (shorter people, elderly and those who do not like even small
heights), then the convenience associated with less frequent bulb-changing may also
affect perceived functionality. For nappies, where changing and disposal are, for some
reluctant people, rather unsavoury, the least smelly or unpleasant mode of operation may
figure as part of functionality, thus altering the total scores again.
It is noteworthy that some of the lightbulb scoring above will be influenced by
very recent developments. Even during the review process of this paper, suggestions
have been made in California, Australia, Canada and the UK/EU that incandescent
24
T. Short and J. Harvey
lightbulbs be banned (California State Assembly, 2007; Hamilton, 2007; Walker and
Macrae, 2007). Alongside the growing debate, prices of bulbs at popular stores (such as
IKEA and Tesco) appear to have fallen. Closer inspection of this latter phenomenon,
however, reveals the same function-related problems already quoted. A search of
www.lightbulbs-direct.com (a UK based lightbulb supplier, prices correct at 30th May
2007) will allow the purchase of a standard, bayonet fit, 40W candle bulb (length 90 mm,
similar to that shown on the right in Figure 1) at £0.45 each. The cheapest green
equivalent is the ‘Economy Energy Saver 8W’ at £3.95; this, however, does not look like
the candle bulb, and is 20 mm longer and has a larger diameter. The “Micro Helix Energy
Saver 7W”, at £4.25, features ‘instant start electronic circuitry’, is only 10 mm longer,
but still does not look like a candle bulb. The ‘Energy Saver Candle 7W’ does look like a
candle bulb, but is 25 mm longer and 15 times the price, at £6.95. Whilst other stores
may provide some of these at a cheaper cost (www.tesco.com shows their equivalent
to the ‘Economy Energy Saver’ at £1.37) the same principle applies: similar functionality
to a normal bulb requires a significant penalty in the form of the purchase price.
Different consumer audiences clearly see the same product in different ways, and rate
it accordingly. Green consumers may rate the cheapness differently in relation to how it
is discounted over time; older or shorter people may define greater convenience as having
to change bulbs less often, and reluctant carers may define the removal of smell and not
seeing faeces as of primary importance. This suggests that an objectives tree intended to
represent all consumers may be flawed – trees with different weightings may be required
for different audiences, representing, for example, the green or the complacent consumer.
Perhaps even the scoring of the same product using the objectives tree would change
depending on the perception of the individual consumer.
Consumers operate in a complex world, much of which is beyond the scope of this
paper. Products, product types, brands and also other completely unrelated products are
all competing for the purchase decision, a decision itself inherently limited by available
money and circumstances, and constrained by psychological factors such as perception of
risk, motivation and personality. Decision making for the consumer is often complex, and
the complexity of a product choice task has been shown to be inversely related to the
extent of the consumer’s external information search (Hu et al., 2007), as well as to
the levels of affect and involvement, attention to marketing communications, product
presentation, perceived costs and benefits (Darke et al., 2006; Tanner, 2006; Wood and
Moreau, 2006; Grimes and Kitchen, 2007).
Tradition is a further influence on the consumer. Consumer psychology would
classify traditionalism-modernism as a form of personality trait that determines consumer
choices, and many customers have become used to ‘traditional’ solutions, however old
that tradition may be. For lightbulbs, it goes back to the 19th century, with little change in
appearance for the electric lightbulb occurring since. The tradition for disposable nappies,
on the other hand, has covered only the last 30 years. According to Cooper (1998), most
successful new products meet the requirements of traditional solutions, but have
something extra. The green lightbulbs in this analysis do not have this extra – in fact their
functionality is significantly less than that of a normal lightbulb, making them accessible
only to the green 20% of consumers. Interestingly, however, one might suggest that,
despite their failings, green lightbulbs are becoming more and more ‘traditional’ – for
many consumers, the slow speed of lighting and the larger appearance are more
acceptable than they used to be. Equally, reusable nappies are becoming increasingly
accepted, with some of the hassle being removed through ‘nappy laundry’ services.
Lightbulbs and nappies: sustainable development and customer perceptions
25
Whether this will be sufficient to generate a new tradition is unclear – reusable nappies
are not new and are not seen as ‘high-technology’, so have no status attached to them
as such. They carry out the same functions, but even with a nappy laundry service, there
is some additional unwanted – and often unpleasant – work.
It can be assumed that, if a green and a normal product appear identical in all ways to
the normal product, the green 20% of the population would value philanthropic idealism
sufficiently to buy the green product. For these identical products, an additional gain for
green would come from a difference in convenience of purchase, in which case the
complacent 60% might buy green. Similarly, if there was Government endorsement of
always buying green where a choice of similar or identical alternatives exists, then the
complacent majority would probably do this. However, if the products are, in effect,
identical, a simpler and less legislative approach might be to persuade or require shops
to give more prominence to the green alternative and make it less easy to select the
non-green option (Harvey, 2005). The two products in this study do not have apparently
identical green and normal versions, and it is likely that more compulsion by the
government in the form of legislation may be required (Harvey, 2005); such legislation
need not directly affect consumers per se, but oblige retailers to change in the first
instance, possibly reducing the choices for normal non-green products. If that is not
effective, the government can have a more direct effect by changing the tax incentives for
the product choices. In the identical and non-identical cases, it is likely that persuasion
(of retailers or consumers) alone will convince the green 20% but have only limited
impact on the complacent 60%, so campaigns of attitude change plus legislation (such as
worked with seat belts in the UK) are likely to be the answer.
6
Conclusion
This paper has taken a novel approach to considering the success or failure of
‘sustainable’ products, by investigating their performance using the simple Functional
Analysis technique. The technique has highlighted the weaknesses inherent in the
engineering design of the energy-efficient lightbulb, whilst also showing the reusable
nappy to be a potential winning product. It has also been put in the context of consumer
psychology to show quite clearly why energy efficient lightbulbs have not taken off in the
way that might have been expected.
The engineering and product designs of a new product are fraught with difficulties,
even for a normal product. Crucial within the design process is the consideration of the
customer – consideration of the customer’s wants and needs; their traditions; and their
likes and dislikes. The simple method of functional analysis, as applied in this paper to
the two products, presents one way of ensuring that both the customers’ needs and the
engineer’s designs are able to match. The successful green product, whilst aided by
Government initiative, will be one that meets the functional needs of all consumers, and
will, therefore, score highly in an objectives tree, irrespective of the specific perceptions
on which that objective tree is based.
For green products to be successful the engineering designer requires a way of
thinking that does not solely apply to the 20% of consumers who consider themselves to
be green – engineers must, at minimum, be targeting the combined green/complacent
80% of the market. In doing so, an enormous commercial opportunity is presented for
companies that are able to design products to meet the expected, traditional, normal
26
T. Short and J. Harvey
functionality but with added green functionality. The green lightbulb has not made use of
this opportunity – whether the reusable nappy has is yet to be seen.
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Appendix
Justification of normal and green lightbulb evaluation
•
Provide fixing. Both bulbs fit standard fixings and therefore gain the full 4/4.
•
Look right. Normal bulbs are the ‘standard’ by which all bulbs are judged, and for
which the vast majority of light shades etc., are designed. Most green bulbs are far
bigger than their normal equivalent (see Figure 1), to the extent that they can stick
out of the top of a light fitting. They produce a different spectrum of light from
normal bulbs, which can be very off-putting to consumers. Some are a completely
different shape in order to restrict the size to that of normal bulbs. ‘Equivalent’ green
bulbs (e.g., 7 W green bulb = 40 W normal bulb) do not appear to provide equivalent
lighting. Most green bulbs do not provide the instant light that normal bulbs provide,
requiring a warm up period.
•
Cheap. This is the purchase price, as ‘running costs’ are effectively covered by the
final two functions. Normal lightbulbs are extremely cheap – e.g., £1 for 3. Green
bulbs are considerably more expensive – e.g., £4 for the cheapest, and more for bulbs
that closer match the look of normal bulbs.
•
Last long. Green bulbs last considerably longer than normal bulbs, but still need
replacing perhaps once a year, depending on usage and number of switches.
•
Use low energy. Relative costs of manufacture are assumed, based on number
of normal lightbulbs sold against number of green bulbs. Use in practice has
a clear distinction – e.g., 40 W as opposed to 7 W, as mentioned earlier. (However,
anecdotal evidence suggests that users of green lightbulbs actually leave the bulbs
on longer, so the situation may be worse than shown).
28
T. Short and J. Harvey
Justification of normal and green nappy evaluation
•
Remove waste. Both are very similar (bearing in mind this analysis is of a specific
reusable nappy), but both can lead to contact with waste material, hence hygiene
can be an issue. Neither is, therefore, the ‘ideal’ solution.
•
Be convenient. The fixing of both is similar, using velcro or something similar,
although the reusable nappy requires assembly first, and so, is a bit more
tricky; on/off is identical; disposal of a disposable nappy is straight into the bin
(which can lead to odour issues), the reusable must be stored ready for washing.
•
Be cheap. Disposable nappies are relatively cheap, but the required frequency of
purchase – typically weekly – sets them apart from, for example, the lightbulbs
discussed earlier. Reusable nappies require a much higher initial outlay, but can
be overtly seen to be saving money on every use.
•
Be reusable. The disposable nappy is not reusable and gains zero, whereas the
reusable nappy gains full marks.
•
Use low energy. The manufacture of disposable nappies requires relatively high
amounts of energy per nappy-use (due to being only single use and containing
super-absorbent crystals) whereas reusable cotton nappies have a much lower energy
requirement. Disposable nappies cannot be cleaned so gain zero for energy in
washing; reusable nappies need washing at relatively high temperatures for proper
cleaning so only gain 2 out of 4.