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DECO3200 · A2 Design Opportunity Pitch
Visual Design Proposal

Beyond
the Bill

Turning household electricity totals into trustworthy explanations for student renters.

Team
Cynthia Cheng
Remaining member names and SIDs to be confirmed before submission.
Challenge area
Climate and environmental sustainability
Household electricity · student renters · Sydney
Evidence base
Exploratory questionnaire · 39 adult responses
Electricity-only scope · Selected direction: Cause Lens
Brief interpretation
Beyond the Bill · 02

Sustainability is not only cleaner technology. It is how people read their own consumption.

We read Designing for Contemporary Challenges through the everyday scene where a person meets environmental sustainability most directly: the electricity, gas and water a household uses. Bills and usage data already exist, but they rarely explain where consumption came from or which behaviours actually mattered.

01 · Broad theme
Climate and energy pressure

Resource use is framed as a global problem, but it is experienced as a monthly or quarterly cost.

02 · What people notice
Cost, not kilowatt-hours

Most residents hold a vague idea of sustainability. What they track is how much this quarter cost them.

03 · Our focus
Student renters

They must manage daily use and bills while holding only partial control over the housing they live in.

The question we are designing against

How can student renters better understand their household resource use, so they can make better-founded and more sustainable choices without giving up too much everyday comfort?

The contemporary challenge
Beyond the Bill · 03

Most student renters are already saving energy. Much of the time they are guessing.

Our questionnaire suggests awareness is not the gap. Respondents described cutting air-conditioning, switching off lights and unplugging devices. What they could not describe was cause.

When a bill rises, the questions residents cannot answer
01What actually caused this amount?
02Are the savings I am making doing anything?
03Is this my habits, or the housing and its equipment?
The challenge, stated

Student renters must control a rising cost of living while holding limited understanding of household utilities and limited control over their housing. Adding more data and more reminders introduces a new pressure rather than resolving the first one.

So the design opportunity is not to make utility use more visible. It is to make it understandable.

Questionnaire finding
n = 39 adult responses
16/39
described a confirmed, concrete electricity-reduction action already in place
2.90/5
mean confidence in identifying which appliances use the most electricity
21/39
worried that acting on more information would mean sacrificing comfort

Exploratory, student-weighted convenience sample. These figures describe reported experience, not prevalence or measured load.

Problem framing
Beyond the Bill · 04

One bill, many causes. The renter carries the cost of all of them.

A single total can carry personal use, housemate routines, a hot-water system, fixed appliances, insulation and shared building services. Those inputs are compressed into one number, and the renter has to decide which part was theirs.

Responsibility
Full

The renter pays the whole amount, on time, regardless of what produced it.

Visibility
Partial

One aggregated figure, arriving weeks or months after the use that created it.

Control
Fragmented

Portable appliances are theirs. Fixed systems, meters and tariffs are not.

Problem statement

Student renters cannot reliably attribute a change in utility use to a specific cause, so even when they are willing to cut back they cannot tell which behaviour is worth changing.

Consequence for quality of life

Uncertainty pushes people to cut the most visible use first, usually cooling and lighting. The larger load may sit in hot water, fixed equipment or dwelling efficiency. Reducing use is not the same as reducing the right use.

Design consequence: do not reduce this to careless behaviour, and do not answer it with another efficiency score.
Scope and evidence boundary
Beyond the Bill · 05

We focus on attribution and agency, not automatic diagnosis.

Three stages we design for
Notice

How a resident finds out that usage or cost has changed in a way worth attention.

Attribute

How they judge whether it came from their own behaviour, shared use or the housing itself.

Act

How they decide what to do next, and whether anyone else needs to be involved.

In scope
  • Household electricity
  • Student and young renters in apartments, student accommodation and shared rentals
  • Bill interpretation, plausible causes and control boundaries
  • Privacy, comfort, anxiety and blame as design constraints
Considered as context
  • Water, hot water and other utility systems as part of the wider household picture
  • Tenancy, metering and embedded-network arrangements as constraints on what a renter can check

Current design judgements rest on electricity-related evidence.

Not claimed
  • Exact appliance consumption without measurement
  • Gas or water findings
  • A representative sample of all Sydney renters
  • Automatic legal, tenancy or technical conclusions
  • Proven energy savings or validated user acceptance
Stakeholders, users and context
Beyond the Bill · 06

The resident experiences the cost. Control is distributed.

The person paying, the people using, the party controlling the equipment and the party holding the data are not the same actor. That separation is why a bill alone cannot settle the question.

Resident
Primary user
Portable appliances
Personal routines
Comfort choices
Household
Housemates
Shared appliances
Occupancy
Splitting agreements
Property
Landlord / agent
Fixed appliances
Repairs
Insulation
Building
Strata / management
Meter access
Shared hot water
Common systems
Billing
Retailer / metering
Tariff
Reading type
Billing period
Renter can act directly
Requires negotiation
Outside the renter's reach
19/39
report little or no control over housemate electricity use
20/39
report little or no control over shared building facilities
Design rule

Every possible cause must show who can check it, without assigning blame or implying that responsibility is legally settled.

Research method and limitations
Beyond the Bill · 07

Four evidence classes narrow the opportunity. None of them validates a product.

Each method has a defined contribution and a defined limit. We label every claim in this document by the evidence class it came from.

01
Anonymous questionnaire
Supports

Exploratory patterns, needs and concerns among student renters.

Does not prove

Prevalence, actual loads or behaviour change.

02
Secondary research
Supports

Structural renter and apartment context: hardship, efficiency, tenancy.

Does not prove

That this sample shares every reported issue.

03
Public online observation
Supports

Plausible breakdowns, renter language and real action routes.

Does not prove

Posters are not participants; replies are not diagnoses.

04
Affinity synthesis
Supports

Traceable themes and research-derived design requirements.

Does not prove

Clusters are not universal, and not user validation.

Evidence labels used throughout this document
Questionnaire finding Secondary research Public online observation Design synthesis Design hypothesis — to be tested
Questionnaire · who answered
Beyond the Bill · 08

A student-weighted exploratory snapshot, not a representative renter sample.

Frozen working snapshot checked 28 August 2026. All respondents confirmed 18+.

Questionnaire finding
39
responses
Student status
Full-time student35 · 89.7%
Part-time student2 · 5.1%
Non-student2 · 5.1%
What this sample supports

Useful exploratory evidence about student and apartment electricity experiences.

What it does not support

A prevalence claim for all Sydney renters, or a claim that all respondents live in apartments.

Residence type
n = 38 valid answers (one blank)
Apartment / unit23 · 60.5%
Student accommodation11 · 28.9%
Independent residence2 · 5.3%
Townhouse1 · 2.6%
Other1 · 2.6%

Because 34 of 38 valid residence answers describe apartments or student accommodation, the findings that follow are read as apartment-weighted.

Insight 01 · The attribution gap
Beyond the Bill · 09

The breakdown is attribution, not visibility and not motivation.

Questionnaire finding
Attribution signals · n = 39
Share of respondents
Confidence ≤ 3 / 5
31/39
Household total is a barrier
22/39
Want appliance / activity information
22/39
Want timing of the increase
21/39
Cannot identify appliance or activity
19/39
2.90/5
mean self-rated confidence in identifying major electricity sources

Self-rated; not an objective knowledge test. Difficulty items were selected, not ranked.

How respondents described their reasoning
“common sense”
“past experience”
“no idea”

Open-text answers, verbatim. Reasoning rests on recall rather than evidence.

Public online observation

Renters commonly discover an anomaly only when a quarterly bill arrives, then work backwards through weeks or months they can no longer reconstruct.

Design consequence

Begin from an unexplained change. Show plausible causes, name the missing evidence, and offer one next check.

Insight 02 · Effort without a target
Beyond the Bill · 10

Residents are already acting. The question is whether the action hits the cause.

Open-text coding
16/39
described a confirmed, concrete reduction action under strict second-pass coding
Retained actions
Reduce heating / cooling time Switch off lights or appliances Unplug devices Use a fan Set a timer
Coding notes

Two ambiguous responses excluded. Intention, awareness and information-seeking were not counted as actions.

AI-assisted, rule-based second-pass audit. Not independent human coding.

The same high bill, four different verdicts
Guess A
Air-conditioner
Guess B
Clothes dryer
Guess C
Refrigerator
Guess D
Hot-water system

Observed in public online threads: several people faced with one bill, offering mutually contradictory causes.

Insight

Without attribution, saving becomes trial and error. Identical effort produces very different results, and the resident has no way to tell which happened.

Design consequence

Replace generic saving reminders with one reversible, hypothesis-specific check, and state what result would support or weaken it.

Insights 03–04 · Control, comfort and trust
Beyond the Bill · 11

Part of the bill was never personal behaviour. And more feedback can itself become a burden.

A single total mixes user-controlled and system-controlled consumption, so reading a high bill as overuse is unreliable. Where the resident cannot act, extra data produces blame, anxiety or unnecessary sacrifice instead of understanding.

Questionnaire finding
Insight 03 · Distributed control · n = 39
Little or no control over shared building facilities
20/39
Little or no control over housemate electricity use
19/39
Recurring in public online observation
Hot-water system running continuously Leaking electric water heater Locked meter rooms Embedded electricity networks Poor dwelling efficiency

The renter needs to distinguish a behaviour question from a housing-system question.

Insight 04 · Wellbeing and trust constraints · n = 39
Concerned about sacrificing comfort
21/39
Anxious about what counts as normal use
20/39
Privacy or monitoring concern
11/39

Public threads describe residents cutting cooling on hot nights even when heat was already affecting sleep, study or a pet. If a system only repeats that usage is high, data becomes pressure without understanding.

Constraints carried into design
ON-DEMAND · MINIMAL DATA · NO HOUSEMATE RANKING · NO MORALISING SCORE
Synthesis and design opportunity
Beyond the Bill · 12

Guess, act, cost. The loop that turns a sustainability theme into an interaction problem.

Design synthesis
Guess
An aggregated number arrives

Residents infer a cause from memory or from whichever appliances are visible.

Act
They cut what is easiest to see

Usually cooling and lighting, often without ever confirming the cause.

Cost
The wrong guess is paid for twice

The household loses comfort, time or trust, and the issue remains unsolved.

Questionnaire

Attribution confidence is low, but willingness to reduce use already exists.

Public online observation

A high bill is followed by guessing, elimination, housemate disputes and suspicion of the housing.

Secondary research

Rental consumption is shaped by structural factors: dwelling performance, infrastructure and billing arrangement.

How might we

help student renters turn an unexplained electricity total into a trustworthy account of what changed, what they can control, and what may require action from another stakeholder — without surveillance, false certainty or unnecessary loss of comfort?

Research-derived design requirements
Beyond the Bill · 13

Seven requirements the research already settles, before any concept is chosen.

These are constraints derived from evidence, not features. Every direction that follows is tested against them.

R1
Timely, user-controlled monitoring

Near-real-time data may serve as evidence, but the resident decides when to look, how much to see, and whether to investigate. No compulsory attention, no frequent reminders, no scores or comparisons.

R2
Explain the change

The design must help the resident understand what changed in this period, not simply restate a total.

R3
Separate evidence from assumption

Where data cannot confirm a cause, the system must not present inference as diagnosis.

R4
Show control boundaries

Each possible cause states whether it sits with the resident, the household, the property, the building or the billing system.

R5
Support a proportionate next step

Prefer small, reversible checks over instructions to cut consumption substantially.

R6
Avoid blame and unnecessary pressure

Do not judge who wasted more, and never treat a sacrifice of comfort as sustainability success.

R7
Make uncertainty useful

When a cause cannot be determined, say what is currently unknown and what further information would settle it. Do not cover uncertainty with an answer that only looks precise.

Ideation process
Beyond the Bill · 14

From measurement to explanation: why we did not default to a dashboard.

We began with the familiar options — smart plugs, whole-home monitors, circuit-level sensing, automatic appliance detection, dashboards and alerts. Each solves part of the problem. None closes the gap between seeing a number and knowing what to do.

Existing approach
Strength
Gap for a renter context
Smart plug
Precise reading for one socket
Covers only plugged-in devices; cannot explain fixed or shared systems
Whole-home monitor
Live total for the dwelling
Shows that use changed, not why
Circuit-level monitor
Finer localisation by circuit
Requires switchboard installation and access a renter may not have
Appliance detection
Attempts automatic identification
Identification is incomplete and carries its own uncertainty
Dashboard / alerts
Continuous visibility
Does not clarify control boundaries or the next action
How Might We prompts that opened divergence
01Help renters understand what caused an unusual bill or usage change?
02Distinguish what residents control from what sits with household, property or building?
03Provide useful information without creating constant monitoring or anxiety?
04Support the next action while the cause is still uncertain?
Divergence, then clustering
24
ideas retained
6
morphology variables
4
affinity clusters
3
concept directions
Sensemaking Timing + wellbeing Agency + handoff
Alternative concept directions
Beyond the Bill · 15

Three directions, three different primary jobs.

Each was developed against the same fields: user need, core interaction, benefit, risk, research basis and prototype feasibility.

Design hypotheses
Direction A
Cause Lens
“Why did this change?”
Primary job

Explain an unexpected bill or usage change using bill facts plus minimal household context, marking what is fact and what is still inference.

Benefit

Direct fit with the attribution evidence.

Risk

False precision; hypotheses read as diagnoses.

FeasibilityHIGH
Direction B
Quiet Signal
“Tell me only when it matters.”
Primary job

Address information arriving too late: flag a meaningful change quietly and let the resident decide whether to look closer.

Benefit

Timely support with low attention demand.

Risk

Alerts may reintroduce the monitoring and anxiety our research warned about.

FeasibilityMEDIUM
Direction C
Renter Evidence Pathway
“Who should deal with this?”
Primary job

Move an unresolved case: collect what is known, what was checked and what remains open, so the resident can speak clearly to a landlord, agent, strata or retailer.

Benefit

Supports distributed control directly.

Risk

Incorrect responsibility guidance; premature escalation.

FeasibilityHIGH · response unknown
Concept selection rationale
Beyond the Bill · 16

Cause Lens scores highest. The matrix supports a decision, not a validation.

Decision record
Criterion
Weight
Cause Lens
Quiet Signal
Evidence Pathway
Research fit
25%
25.0
20.0
17.5
Actionability
20%
18.0
16.0
18.0
Trust and explainability
15%
12.0
9.0
12.0
Privacy and wellbeing
15%
13.5
9.0
12.0
Prototype feasibility
15%
13.5
12.0
12.0
Renter agency and equity
10%
8.0
6.0
10.0
Total
100%
90.0
72.0
81.5
Why Cause Lens

The strongest evidence we hold points at one thing: residents cannot explain why a bill changed. Cause Lens is also the only direction that can be prototyped honestly with transparent rules and fictional data, without pretending to hold appliance-level sensors.

Deferred, with reasons

Quiet Signal needs long-run usage data before “unusual” means anything, and risks the monitoring pressure we found.

Renter Evidence Pathway stays valuable for structural cases, but questionnaire demand for reporting is clearly weaker than for attribution. It becomes the follow-on route for unresolved cases.

Selected direction · Cause Lens
Beyond the Bill · 17

Cause Lens turns one unexplained period into a transparent explanation case.

On-demand, evidence-labelled, and designed to stop where the available data stops. It converts real or near-real-time usage information into an explanation the resident can act on.

Design hypothesis — to be tested
Stage 01
What changed?

Confirm what actually moved: billing period, days, kWh, cost, tariff, actual or estimated reading, and the closest comparable period.

Stage 02
What might explain it?

A small set of possible causes, each carrying its supporting evidence and its missing evidence. No percentages without measurement.

Stage 03
Who can act?

Each cause maps to a control boundary: resident, household, property, building or billing system. No automatic assignment of responsibility.

Stage 04
What next?

One low-risk, reversible check, with a statement of what result would support or weaken the hypothesis.

Uncertainty is an interaction state, not fine print
Known fact

Directly supplied by the bill or confirmed by the resident.

e.g. the meter reading is marked actual, not estimated.

Supported hypothesis

Consistent with some available evidence, but not confirmed by measurement.

e.g. cooling use changed during the hot weeks of the period.

Open question

Cannot be resolved with current information; needs more data or another stakeholder.

e.g. there is no comparable earlier reading to compare against.

Boundary. Cause Lens does not claim exact appliance measurement, and it is not an always-on efficiency score. Where evidence runs out, it says so.
Interaction sequence · screens 01–04
Beyond the Bill · 18

Maya needs orientation before she needs advice.

Fictional scenario. A quarterly bill of $487.60 arrives higher than expected. One housemate blames the air-conditioner, but the period is seven days longer than the last one and the cause is unresolved. The scenario exists to make the interaction testable; it is not a participant story.

Low-fidelity wireframe
01Start
What are you trying to understand?
A higher bill than expected
A usage change
A comfort problem
Something else
Privacy: you can continue without uploading a bill.
Start a case

Entry is a question, not a dashboard. Nothing is monitored until the resident asks.

02Known facts
First, separate facts from guesses.
Billing period98 days
Total cost$487.60
Total usage— kWh
Reading typeActual
Previous period91 days
KNOWN FACT · 4
OPEN QUESTION · 1
The period is 7 days longer. Totals are not directly comparable.

Facts and gaps are shown together, so the resident sees what the bill cannot tell them.

03Context
What changed during this period?
People at home
MoreSameLess
Heating or cooling
MoreSameLess
Hot water behaviour
ChangedUnsure
Unusual appliance or building event?
Skip this questionWhy we ask

Four short questions. Every one is skippable and explains why it is being asked.

04Cause cards
These explanations fit some evidence.
KNOWN FACT
Longer billing period
Resident · billing
SUPPORTED HYPOTHESIS
Increased cooling in hot weeks
Resident · household
SUPPORTED HYPOTHESIS
Hot-water system running longer
Property · building
OPEN QUESTION
Shared or common-area load
Building · billing
No exact percentages are shown. None can be measured from this bill.

Each card carries its evidence state, its supporting and missing evidence, and who can check it.

Interaction sequence · screens 05–08
Beyond the Bill · 19

Control, then one reversible check, then a recorded outcome.

The case ends in a state, not a verdict: resolved, revised, or carried forward as a private summary the resident chooses whether to share.

Low-fidelity wireframe
05Control map
What can be checked, and by whom?
I CAN CHECK
Cooling hours · appliance timers
WE CAN DISCUSS
Shared appliance use · occupancy
PROPERTY MAY CHECK
Hot-water system · fixed appliances
RETAILER MAY CHECK
Tariff · reading · billing period
Who can check is not the same as who is responsible. No legal conclusion is drawn.

Boundaries are described as capability to check, never as fault.

06Next step
Try one reversible check.
Note hot-water heating times for one week
EffortLow
Comfort impactNone
ReversibleYes
WHAT THE RESULT WOULD MEAN
Continuous heating supports the hot-water hypothesis. Short cycles weaken it.
Start this check
Choose a different cause

One check at a time, chosen for low effort and no comfort cost.

07Follow-up
What happened after the check?
The pattern changed
No meaningful change
Could not complete the check
New information appeared
CASE UPDATED
Hot-water hypothesis weakened. Shared-load question remains open.
Record outcome

A negative result is information. Recording it is what makes the next guess better.

08Resolve / export
What should happen next?
Close the case
Revise and try another cause
Save a private summary
Prepare a summary for someone else
SUMMARY WOULD INCLUDE
Period facts · checks attempted · outcomes · what is still open
Nothing is sent anywhere. Sharing remains under the resident's control.

Export exists for unresolved cases only, and is never the default path.

Direction moving forward
Beyond the Bill · 20

The next phase tests comprehension and usefulness, not energy savings.

The interaction hypothesis to falsify: that a resident can understand an explanation carrying evidence and uncertainty, and make a better-founded decision about what to do next.

Not yet conducted
To build
Clickable prototype

A low- to mid-fidelity Cause Lens flow built on a fictional but plausible high-bill scenario: bill facts, a few contextual questions, cause cards, control boundaries and one reversible next action.

To observe
Human evaluation focus
  • Can they distinguish fact, hypothesis and open question?
  • Do they understand why a cause was proposed?
  • Can they identify what sits inside their control?
  • Does it read as help, or as monitoring and blame?
  • What information feels necessary, intrusive or unavailable?
Decision rule
What each result means
CONTINUE
People understand the uncertainty and choose a proportionate action.
REVISE
Hypotheses are mistaken for diagnoses, or advice feels like a demand to sacrifice comfort.
RECONSIDER
Attribution is not seen as useful, or the minimum data required is unacceptable.
What this proposal does not claim

No participant walkthrough, expert walkthrough, tutor feedback or user-acceptance evidence has been collected. Human evaluation is deliberately left for the team to conduct with the required permissions.

Evidence the next phase must return

Approved participant boundary · task script · consented anonymised observations · prototype version · a feedback-to-change record · evidence storage location.

References · APA 7
Beyond the Bill · 21

Sources used in the main proposal

Australian Energy Regulator. (n.d.). Embedded networks customers.

Chalal, M. L., Medjdoub, B., Bezai, N., Bull, R., & Zune, M. (2022). Visualisation in energy eco-feedback systems: A systematic review of good practice. Renewable and Sustainable Energy Reviews, 162, 112447.

Chatzigeorgiou, I. M., & Andreou, G. T. (2021). A systematic review on feedback research for residential energy behavior change through mobile and web interfaces. Renewable and Sustainable Energy Reviews, 135, 110187.

Daniel, L., Moore, T., Baker, E., Beer, A., Willand, N., Horne, R., & Hamilton, C. (2020). Warm, cool and energy-affordable housing policy solutions for low-income renters (AHURI Final Report No. 338). Australian Housing and Urban Research Institute.

Department of Climate Change, Energy, the Environment and Water. (2024). Aligning home energy ratings: Research report.

Dritsa, D., & Houben, S. (2024). How design researchers make sense of data visualizations in data-driven design: An uncertainty-aware sensemaking model. ACM Transactions on Computer-Human Interaction, 31(6), Article 72.

Easthope, H., Palmer, J., Sharam, A., Nethercote, M., Pignatta, G., & Crommelin, L. (2023). Delivering sustainable apartment housing: New build and retrofit (AHURI Final Report No. 400). Australian Housing and Urban Research Institute.

Energy Consumers Australia. (2025). Understanding and measuring energy hardship in Australia.

Franzke, A. S., Bechmann, A., Ess, C. M., Zimmer, M., & Association of Internet Researchers. (2020). Internet research: Ethical guidelines 3.0.

NSW Government. (n.d.). Connection and supply of electricity and gas in rental properties.

Project team. (2026). Anonymous household electricity questionnaire [Unpublished raw data]. Live data checked 28 August 2026, n = 39.

Project team. (2026). Beyond the Bill data and coding audit workbook [Unpublished internal document].

Extended verification notes, the public online observation record and the generative-AI provenance ledger appear in the appendix.

Sources rechecked 28 Aug 2026

Beyond the Bill · DECO3200 A2

Appendix

Supporting evidence, method boundaries, the full ideation record, concept sheets, prototype specification and the generative-AI provenance ledger.

A · Method and coverage
B · Data cutoff and coding
C1 · Aggregate results
C2 · Control and first actions
D · Affinity synthesis
E1 · Secondary research table
E2 · Research shaping interaction
F · Online observation corpus
G1 · Evidence ledger
G2 · Open assumptions
H1 · HMW derivation
H2 · Raw idea bank
I1–I3 · Ideation sheets
J · Morphological exploration
K1–K3 · Concept sheets
L · Selection matrix
M1–M3 · Journey and flow
N1–N2 · Prototype content
O · Critique and risk log
P · Provenance and AI ledger
Appendix A · Research method and questionnaire coverage
Supporting evidence

Anonymous online questionnaire, secondary research, public observation and affinity synthesis.

The questionnaire explored living context, bill access, attribution confidence, saving actions, perceived control, information needs, and privacy, anxiety and comfort concerns.

Questionnaire purpose

Explore how student renters access, read and respond to household electricity information, and what constraints shape their response.

Participant boundary

Adults aged 18 and over. Convenience sample, strongly student-weighted. No bill upload, address or account information was required.

Evidence limit

Self-report supports exploratory needs and concerns. It does not measure appliance loads, diagnose building faults, prove prevalence or validate a concept.

Question coverage
Living context
Student status · residence type · household composition
Access + interpretation
Bill access · understanding totals · attribution confidence
Attribution + action
Likely sources · reduction actions · first action routes
Control + concerns
Housemates · building facilities · comfort · anxiety · privacy
Appendix B · Data cutoff, denominator and coding rules
Supporting evidence

Frozen working snapshot: 28 August 2026.

39
response rows retained
38
valid residence responses
16
confirmed concrete reduction actions
2
ambiguous actions excluded
Inclusion rule

Count only a concrete action reasonably expected to reduce electricity use: reducing heating or cooling time, switching off or unplugging devices, using a fan, or setting a timer.

Exclusion rule

Do not count intention, awareness, information seeking, paying the bill, contacting a stakeholder, using an app, buying a monitor without a reduction action, “nothing”, or unclear language.

Audit status

AI-assisted, rule-based second-pass audit. No discrepancy was found against the strict 16 / 39 result. This is not an independent human coding check and does not replace one, should the team choose to perform it.

Appendix C1 · Anonymised aggregate questionnaire results
Supporting evidence

All figures use n = 39 unless marked otherwise.

Metric
Count
Denom.
Interpretation boundary
Confidence ≤ 3 / 5
31
39
Self-rated; not an objective knowledge test
Household total is difficult
22
39
Selected difficulty; not ranked
Cannot identify appliance or activity
19
39
Does not validate automated diagnosis
Want appliance or activity information
22
39
Does not establish an interface preference
Want timing information
21
39
Does not validate always-on monitoring
Confirmed reduction action
16
39
No measured savings or effectiveness
Comfort sacrifice concern
21
39
Hypothetical concern, not product feedback
Anxiety about normal use
20
39
Hypothetical concern, not product feedback
Privacy or monitoring concern
11
39
Checkbox selection, not a severity scale
Appendix C2 · Control and first-action distributions
Supporting evidence

The questionnaire points to several possible actors rather than one universal route.

Perceived control · n = 39
Little or no control: public building facilities
20/39
Little or no control: housemate use
19/39
Design implication

Attach every cause hypothesis to a control boundary and an appropriate next check. Do not assign automatic legal responsibility, and do not guarantee a stakeholder response.

First action for a suspected appliance or facility problem
Supplier / retailer
9
Household / housemates
8
Landlord / agent
7
Property / strata
4
Do not know
3
Self-investigation
tbc

The self-investigation count is not yet confirmed in the frozen snapshot and must be filled from the source workbook before submission. All other counts are as recorded.

First actions are distributed across supplier, household, landlord or agent, strata or property, self-investigation and “do not know”. There is no single action route.

Appendix D · Affinity synthesis and design clusters
Supporting evidence

Questionnaire, secondary and public-observation evidence converged around six breakdowns.

Clusters are traceable to source evidence, but they are not universal and they are not user validation.

Visibility

Information arrives delayed or aggregated.

Attribution

The total cannot be connected to a cause or a moment.

Agency

The resident may not control the relevant system.

Action

The next check or contact route is unclear.

Comfort

Saving can conflict with health, study and sleep.

Equity

Structural constraints can be mistaken for carelessness.

Synthesis

The strongest opportunity is not “make people use less”. It is helping renters turn incomplete information into an explanation and a proportionate action, while preserving comfort.

Appendix E1 · Secondary research evidence table
Supporting evidence

What each source supports, and what it does not prove.

Source
Evidence used
Supports
Does not prove
Energy Consumers Australia (2025)
Renters disproportionately affected; hardship indicators and an insulation gap
Structural context and comfort risk
The cause in any specific home
Daniel et al. (2020)
Limited rental control and split incentives
Agency and property constraints
That this sample has identical barriers
Easthope et al. (2023)
Apartment sustainability spans dwelling, building and governance
Multiple system levels in one bill
That a digital product is the best response
DCCEEW (2024)
Dwelling and apartment-complex ratings describe different levels
System-level clarity matters
That ratings explain a bill

Verification date: 28 August 2026 · primary or recognised research sources only for the claims used.

Appendix E2 · Research that shapes the interaction
Supporting evidence

Feedback design, network arrangements and uncertainty boundaries.

Source
Finding used
Design implication
Boundary
Chatzigeorgiou & Andreou (2021)
Digital feedback is promising, with no single reliable average effect
Test explanation quality, not assumed savings
Does not validate Cause Lens
Chalal et al. (2022)
Visualisation should fit information purpose, user profile and scenario
Case-based explanation; avoid decorative data density
Does not prescribe this interface
AER (n.d.)
Embedded-network seller arrangements and protections may differ
Ask for network or provider context before suggesting a contact route
Not individual legal advice
NSW Government (n.d.)
Responsibility depends on metering, tenancy and supply arrangement
Do not assign automatic responsibility
Not case-specific legal advice
Dritsa & Houben (2024)
Data quality, visuals and viewer background shape how uncertainty is read
Expose evidence quality and missing data
The three-state model remains to be tested

Franzke et al. (2020) informs the public-observation ethics boundary recorded in Appendix F.

Appendix F · Public online observation corpus and ethics boundary
Supporting evidence

Observed 21 August 2026; paraphrased and anonymised for analysis.

Threads were read only as publicly posted. No contact was made, no comments or private messages were sent, and no bill images or addresses were copied.

OE-01
Whirlpool · unexpectedly high hot-water usage
meter access · hot water · escalation
OE-02
Whirlpool · embedded-network billing question
reading history · embedded network · baseline
OE-03
Whirlpool · embedded network arrangement
hidden arrangement · choice · trust
OE-04
Reddit · high apartment power usage
comparison · locked meter · shared load
OE-05
Reddit · who pays for an electrician?
responsibility · investigation cost · action route
OE-06
Reddit · high electricity bill advice
units · period · context · comparison
Ethics boundary

Public posters are not project participants. Their replies are hypotheses circulating in a forum, not verified diagnoses, and are used here only to identify plausible breakdowns, renter language and real-world action routes. Approach follows Franzke et al. (2020).

Appendix G1 · Evidence, assumption and unknown ledger
Supporting evidence

Questionnaire evidence IDs QD-01 to QD-10.

ID
Current evidence
Design implication
What it cannot prove
QD-01
22 / 39: household total is difficult
Explain the change, not another total
That every bill lacks useful information
QD-02
19 / 39: cannot identify the source
Show hypotheses and evidence gaps
Automated appliance diagnosis
QD-03
Mean confidence 2.90 / 5
Plain language and clear provenance
An objective knowledge level
QD-04
22 want source; 21 want timing
Prioritise cause and change over totals
A preferred interface or alert model
QD-05
16 / 39 concrete actions
Improve targeting, not motivation
Savings magnitude or success
QD-06
Comfort 21; anxiety 20; privacy 11
Avoid surveillance and pressure
Reaction to a tested product
QD-07
Control limits: building 20; housemates 19
Show control boundaries explicitly
An identical interpretation of control
QD-08
First actions spread across actors
Connect each explanation to an actor
Which route succeeds
QD-09
4 raised an issue; 5 want reporting evidence
Keep export secondary
Handoff as the primary demand
QD-10
11 / 39: information arrives too late
Timing is a future variable
Always-on monitoring
Appendix G2 · Open assumptions and falsifiable unknowns
Supporting evidence

These items move into future human evaluation. They are not treated as findings.

Design assumptions
  • Residents will understand and trust known, supported and open states.
  • Four short context questions can improve orientation without excessive burden.
  • A reversible next check will feel more useful than a generic saving tip.
  • Residents can recognise when an issue sits outside their control.
  • A private evidence summary can help unresolved cases without encouraging premature escalation.
Open questions
  • Which information source is trusted first?
  • What is the most important breakdown: noticing, understanding, acting or responsibility?
  • How do renters balance cost against comfort, health, study and household fairness?
  • Does clearer attribution change a decision, or support a repair request?
  • What minimum data feels necessary, intrusive or unavailable?
Status · untested

Requires real participant evidence before any claim of comprehension, usefulness or acceptance.

Appendix H1 · How Might We derivation
Supporting evidence

Evidence pattern → insight → generative question.

Evidence pattern
Insight
How might we
Aggregated totals with low confidence
Residents need explanation, not only visibility
Move from a total to plausible causes?
Demand for source and timing information
Cause and change are the high-priority needs
Explain what changed, and when?
Saving actions without attribution
Motivation exists; action may be poorly targeted
Test a cause before sacrificing comfort?
Distributed control
A resident cannot act on every cause
Show who can check or change each part?
Anxiety, privacy and misleading information
More data may create harm
Support without surveillance or false certainty?
Appendix H2 · Raw idea bank
Supporting evidence

24 ideas retained before clustering and selection.

Generated through brainwriting against the five How Might We prompts. Cluster colour indicates the primary job each idea addresses.

01
Bill Decoder
02
Change Timeline
03
Cause Cards
04
Actual / Estimated Check
05
One-Question Diagnosis
06
Reversible Experiment Planner
07
Comfort Boundary
08
Household Context Snapshot
09
Appliance Use Diary
10
Hot-Water Pathway
11
Control Boundary Map
12
Who Can Check This?
13
Quiet Anomaly Alert
14
No-Score Mode
15
Notification Budget
16
Own-History Comparison
17
Shared-House Discussion Card
18
Evidence Pack
19
Contact Route Finder
20
Missing Data Checklist
21
Confidence Legend
22
Privacy Preview
23
Resolution Log
24
Stop Rule
Sensemaking
Timing + wellbeing
Agency + handoff
Appendix I1 · Ideation sheet A — Sensemaking
Supporting evidence

Ideas 01–06, 20–21 · explaining an unexpected total

Sketch slots below are reserved for the team's hand thumbnails. Idea IDs and captions are final.

Sketch to insert
01
Bill Decoder — plain-language reading of the total
02
Change Timeline — before and after comparison
03
Cause Cards — evidence-labelled possible causes
04
Actual / Estimated Check — is the reading real?
05
One-Question Diagnosis — guided, one step at a time
06
Reversible Experiment Planner — test one cause safely
20
Missing Data Checklist — what we still do not know
21
Confidence Legend — three-state evidence key
Appendix I2 · Ideation sheet B — Agency and handoff
Supporting evidence

Ideas 11–12, 17–19, 22–24 · renter agency and unresolved cases

Sketch slots reserved for the team's hand thumbnails.

Sketch to insert
11
Control Boundary Map — resident to retailer
12
Who Can Check This? — route by actor
17
Shared-House Discussion Card — no ranking
18
Evidence Pack — what was checked, what is open
19
Contact Route Finder — official links only
22
Privacy Preview — see exactly what is shared
23
Resolution Log — outcomes over time
24
Stop Rule — where the system must not proceed
Appendix I3 · Ideation sheet C — Timing and wellbeing
Supporting evidence

Ideas 07–09, 13–16 and the on-demand case

Sketch slots reserved for the team's hand thumbnails.

Sketch to insert
07
Comfort Boundary — a floor the system will not push past
08
Household Context Snapshot — minimal input
09
Appliance Use Diary — temporary, opt-in
13
Quiet Anomaly Alert — low-pressure flag
14
No-Score Mode — no rating, no comparison
15
Notification Budget — a hard cap the user sets
16
Own-History Comparison — never against neighbours
→ SELECTED
On-demand explanation case — became Cause Lens
Appendix J · Morphological exploration and clustering
Supporting evidence

Six variables were recombined to avoid defaulting to a dashboard.

Variable
Option 1
Option 2
Option 3
Option 4
Trigger
Bill arrival
Unusual change
Comfort problem
User question
Input
Bill history
Retailer interval data
Household context
Optional device data
Explanation
Timeline
Cause cards
Control map
Guided questions
Action
Self-check
Household discussion
Retailer query
Property escalation
Uncertainty
Known fact
Supported hypothesis
Open question
Conflicting evidence
Delivery
On-demand case
Opt-in alert
Periodic review
Exportable summary
Cause Lens

User question + bill/context + cause cards + self-check + explicit uncertainty + on-demand case

Quiet Signal

Unusual change + interval data + timeline + investigate or dismiss + uncertainty + opt-in alert

Renter Evidence Pathway

Unresolved problem + bill/context evidence + control map + escalation + missing-data statement + export

Appendix K1 · Concept sheet — Cause Lens
Supporting evidence

Cause Lens

Selected direction
User need

“Tell me what may have changed, how strong the evidence is, and what I can check next.”

Core interaction

Select period → confirm known facts → answer minimal context → review evidence-labelled cause hypotheses → see the control map → try one reversible check.

Expected benefit

Closest fit with the attribution evidence and with the stated need for source and timing information.

Main risk

False precision, household sensitivity and interface complexity.

Risk response

Three uncertainty states, minimal data collection, no appliance percentages without measurement, and an on-demand case rather than continuous monitoring.

Research basis

QD-01–05 · OE-01 / 02 / 04 · secondary research

Prototype feasibility

High, for a fictional-data low- to mid-fidelity prototype.

Appendix K2 · Concept sheet — Quiet Signal
Supporting evidence

Quiet Signal

Deferred
User need

“Tell me when something genuinely changes, without making me monitor electricity every day.”

Core interaction

Opt in → set sensitivity and quiet periods → receive a low-pressure flag → see why it appeared → investigate, dismiss or mute.

Expected benefit

Responds to the timing need with a low attention demand.

Main risk

Anxiety, false alerts, a sense of surveillance, and unavailable longitudinal data.

Risk response

Optional and infrequent, compared only against the household's own history, with transparent data requirements and mute controls.

Research basis

QD-04 / 06 / 10 · secondary research

Prototype feasibility

Medium. The interaction can be prototyped; the detection cannot yet be validated.

Appendix K3 · Concept sheet — Renter Evidence Pathway
Supporting evidence

Renter Evidence Pathway

Follow-on route
User need

“Help me explain what happened, what I checked, and who may be able to respond.”

Core interaction

Build a timeline → check evidence → map control and responsibility uncertainty → see official contact routes → export a resident-controlled summary.

Expected benefit

Reduces the effort of carrying an unresolved case across several actors.

Main risk

Incorrect legal or technical guidance, premature escalation, and handling sensitive account data.

Risk response

No legal conclusions, official links only, wording that depends on the actual arrangement, and export controlled entirely by the resident.

Research basis

QD-07–09 · OE-01 / 03 / 05 · secondary research

Prototype feasibility

High for the case-building flow. Stakeholder response remains external and untestable here.

Appendix L · Selection matrix and decision record
Supporting evidence

Five-point ratings converted through six evidence-derived weights.

Criterion
Weight
Cause Lens
Quiet Signal
Evidence Pathway
Research fit
25%
5 · 25.0
4 · 20.0
3.5 · 17.5
Actionability
20%
4.5 · 18.0
4 · 16.0
4.5 · 18.0
Trust and explainability
15%
4 · 12.0
3 · 9.0
4 · 12.0
Privacy and wellbeing
15%
4.5 · 13.5
3 · 9.0
4 · 12.0
Prototype feasibility
15%
4.5 · 13.5
4 · 12.0
4 · 12.0
Renter agency and equity
10%
4 · 8.0
3 · 6.0
5 · 10.0
Total
100%
90.0
72.0
81.5
Selected

Cause Lens — closest evidence fit, and honest to prototype with fictional data.

Deferred

Quiet Signal needs longitudinal data. Renter Evidence Pathway has weaker demand as the primary job. Also deferred: longitudinal anomaly detection, automatic appliance percentages, default escalation.

Appendix M1 · Current and proposed journey
Supporting evidence

Fictional scenario: Maya receives an unexpectedly high bill.

The scenario exists to make the interaction testable. It is not a participant story.

Stage
Current experience
Cause Lens experience
Trigger
An unexpected total arrives
Start an on-demand explanation case
Orientation
Ask whether the total is normal
Check period length, tariff, reading type and baseline
Attribution
Guess from visible appliances or memory
Review a small set of evidence-labelled hypotheses
Control
Cut whatever is easiest to control
Map each cause to resident, household, property, building or billing
Action
Search, ask others, or reduce comfort
Try one reversible check, or an appropriate contact route
Follow-up
The result is rarely recorded
Record the outcome; resolve, revise or export

Fictional data throughout. No diagnosis is claimed at any stage.

Appendix M2 · Eight-frame storyboard
Supporting evidence

Maya moves from a visible total to evidence, control and one next check.

Frame slots reserved for the team's illustrations. Captions are final.

Illustration to insert
1The bill arrives
2The household starts guessing
3She starts a case
4Facts are separated from gaps
5She adds a little context
6She reviews the hypotheses
7She maps who can check what
8She records the outcome
Appendix M3 · Interaction flow and decision points
Supporting evidence

The system must stop, or expose uncertainty, when evidence is missing.

START
Bill, usage or comfort question
FACTS
Period · reading type · comparable baseline
CONTEXT
Occupancy · comfort · hot water · unusual events
HYPOTHESES
Known · supported · open
CONTROL
I · household · property · building · retailer
NEXT CHECK
One reversible action, plus what its result would mean
OUTCOME
Changed · unchanged · unable · new evidence
END
Resolve · revise · save or export
Stop states
Insufficient data Safety concern Requires authorised meter or building access Legal or technical uncertainty

In any stop state the case does not proceed to a conclusion. It states what is unknown and what would be needed to continue.

Appendix N1 · Prototype content specification, screens 01–04
Supporting evidence

Copy and evidence-state rules for the clickable prototype.

01 · START
What are you trying to understand?
Higher bill · usage change · comfort problem · other
Privacy rule: the resident can continue without uploading a bill.
02 · KNOWN FACTS
First, separate facts from guesses.
Billing period · total cost · total kWh · actual or estimated reading · previous comparable period
Any field the resident cannot supply is shown as an open question, not silently omitted.
03 · CONTEXT
What changed during this period?
Residents · time at home · heating and cooling · hot water · unusual appliance or building event
Questions are skippable and each explains why it is asked.
04 · CAUSE CARDS
These explanations fit some evidence.
Each card carries: evidence state · possible cause · supporting evidence · missing evidence · who can check it
No exact percentages without measurement.
Appendix N2 · Prototype content specification, screens 05–08
Supporting evidence

Control, action, follow-up and resident-controlled export.

05 · CONTROL MAP
What can be checked, and by whom?
I can check · we can discuss · property may check · retailer may check
No automatic responsibility assignment.
06 · NEXT STEP
Try one reversible check.
Action · effort · comfort impact · what result would support or weaken the hypothesis
Only one check is offered at a time.
07 · FOLLOW-UP
What happened after the check?
Pattern changed · no meaningful change · could not complete · new information appeared
A negative result updates the case rather than closing it.
08 · RESOLVE / EXPORT
What should happen next?
Close · revise · save a private summary · prepare a summary for another stakeholder
Sharing remains under resident control.
Appendix O · Critique, iteration and risk log
Supporting evidence

Version 0.1 to 0.2: what the evidence removed.

Internal evidence-led critique only. No human feedback has been collected.

Version 0.1 issue
Evidence / risk
Version 0.2 change
Unresolved risk
Continuous dashboard and alerts
Anxiety, privacy and comfort concerns
On-demand explanation case
May still feel burdensome
Exact appliance breakdown
No appliance-level measurement exists
Evidence-labelled hypotheses
Hypotheses may be mistaken for diagnoses
Many competing features
Attribution, timing and handoff were mixed
Attribution becomes the primary job
Scope may still expand
Escalation on the main screen
Direct reporting demand is secondary
Export only for unresolved cases
May still prompt premature contact
Household score or comparison
Blame and moral judgement
No ranking; own history only
Household conflict remains possible
Generic saving tips
Residents already act
One reversible, hypothesis-specific check
The check may not reduce uncertainty
Next human evidence needed
Comprehension of uncertainty Perceived blame or pressure Data burden Usefulness of the control map Interpretation of stop states
Appendix P · Research log, provenance and generative-AI acknowledgement
Supporting evidence

Conservative disclosure: assistance, generated assets and human evidence are recorded separately.

The team remains responsible for accuracy, course compliance, final concept decisions and submission.

Overall assistance

Generative AI assisted ideation, evidence organisation, draft interaction content, concept comparison and visual production of this document.

Generated visual assets in this version

None. All figures in this document are drawn from questionnaire data or authored as diagrams and wireframes. The ideation sheets (I1–I3) and the storyboard (M2) carry reserved slots labelled for the team's own sketches.

What AI output does not represent

No participant feedback, expert walkthrough, tutor feedback, workshop photograph, team consensus, user acceptance, measured energy saving, legal advice, or proof that Cause Lens works.

Source verification

Questionnaire exported and re-audited 28 August 2026. Official and academic sources rechecked 28 August 2026. Public online observation recorded 21 August 2026.

Image-prompt ledger — to attach if generated assets are added

Four prompts (P01 sensemaking ideation sheet, P02 agency and handoff ideation sheet, P03 timing and wellbeing ideation sheet, P04 eight-frame storyboard) are held verbatim in AI_Prompt_Ledger.txt. If the team inserts generated images into I1–I3 or M2, paste the exact prompt text and the file's SHA-256 hash onto a page per asset here before submission.