Reducing hot water consumption with behavioral interventions

Last registered on February 07, 2023


Trial Information

General Information

Reducing hot water consumption with behavioral interventions
Initial registration date
November 07, 2019

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
November 08, 2019, 10:11 AM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
February 07, 2023, 3:14 AM EST

Last updated is the most recent time when changes to the trial's registration were published.



Primary Investigator

University of Zurich

Other Primary Investigator(s)

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Various interventions have been shown to effectively reduce private households’ energy consumption. We evaluate a randomized controlled trial in the context of the ‘Hot Water Challenge’, an intervention focused on hot water consumption, to address three research questions. Can regret enhance the effectiveness of traditional lotteries as a tool to incentivize households? For which type of household are social comparison interventions effective? Does an intervention focused on hot water consumption lead to spillovers on cold water or heating energy consumption?
External Link(s)

Registration Citation

Mayr, Harald. 2023. "Reducing hot water consumption with behavioral interventions." AEA RCT Registry. February 07.
Experimental Details


Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Chapter 2: percent change in hot water consumption
Chapter 3: percent change in hot water consumption
Chapter 4: percent changes in hot water consumption, cold water consumption, heating energy consumption
Primary Outcomes (explanation)
"Percent change" refers to the average percent change in consumption between the baseline period (September) and the intervention periods October to January (see the attached pre-analysis plan for a formal definition).

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The field experiment addresses three distinct research questions in a cross-randomized design. The Control group (20% of the sample) does not receive any intervention. The remaining 80% of the sample receive individual hot water consumption feedback, a 5% savings target, and intervention components randomized along two dimensions:

- The type of lottery (StandardLottery vs. RegretLottery, described in detail in chapter 2 of the attached pre-analysis plan)
- Social comparison (NoComparison vs. Comparison, described in chapter 3 of the attached pre-analysis plan)

The effects of these aggregated interventions, as compared to the Control group, are subject of chapter 4 of the attached pre-analysis plan.
Experimental Design Details
Randomization Method
Randomization Unit
Chapter 2: household
Chapter 3: household
Chapter 4: building
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Chapter 2: 3,814 households
Chapter 3: 3,814 households
Chapter 4: 782 buildings
Sample size: planned number of observations
Chapter 2: 3,814 households Chapter 3: 3,814 households Chapter 4: 4,775 households
Sample size (or number of clusters) by treatment arms
Control: 961 households
A (StandardLottery & NoComparison): 953
B (RegretLottery & NoComparison): 953
C (StandardLottery & Comparison): 954
D (RegretLottery & Comparison): 954

See the attached pre-analysis plan for descriptions of group names Control, A, B, C, D.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
ETH Ethics Commission Office
IRB Approval Date
IRB Approval Number
EK 2019-N-85
Analysis Plan

Analysis Plan Documents

Pre-Analysis Plan 'Hot Water Challenge'

MD5: 4c21dcba2c198210abd79a5092f6a30b

SHA1: 28b2cbb42bc7e8a78e404da2bfe85f748b7a1c1c

Uploaded At: November 07, 2019


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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials