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Do Energy Efficiency Investments Deliver? Evidence from the Weatherization Assistance Program
Last registered on January 27, 2015


Trial Information
General Information
Do Energy Efficiency Investments Deliver? Evidence from the Weatherization Assistance Program
Initial registration date
January 27, 2015
Last updated
January 27, 2015 11:14 PM EST
Primary Investigator
UC Berkeley
Other Primary Investigator(s)
PI Affiliation
University of Chicago
PI Affiliation
University of California, Berkeley
Additional Trial Information
Start date
End date
Secondary IDs
Conventional wisdom suggests that individuals and firms fail to undertake energy efficiency investments that are predicted by engineering models to have private returns greatly in excess of their costs. Policymakers have seized on this so-called "energy efficiency gap" with a wide variety of interventions that promise both private benefits and reductions in environmental damages, especially declines in the greenhouse gases that cause climate change. This study applies experimental and quasi-experimental techniques to assess the private and social returns to energy efficiency investments using detailed data from the application of the nation’s largest residential energy efficiency program, the Federal Weatherization Assistance Program (WAP), in Michigan. We find that participating households’ energy consumption declined significantly. We also present suggestive evidence that households modestly increased indoor temperatures by about 0.6 degrees F, providing some of the first direct evidence on compensatory response to a reduction in the price of energy services (i.e., the “rebound” effect) in the building sector. Accounting for the energy savings and consumers’ valuations of the higher indoor temperatures, the data indicate that these investments have negative annual returns both privately and socially (i.e., when the monteized value of the greenhouse gas savings are included).
External Link(s)
Registration Citation
Fowlie, Meredith, Michael Greenstone and Catherine Wolfram. 2015. "Do Energy Efficiency Investments Deliver? Evidence from the Weatherization Assistance Program." AEA RCT Registry. January 27. https://doi.org/10.1257/rct.416-1.0.
Former Citation
Fowlie, Meredith et al. 2015. "Do Energy Efficiency Investments Deliver? Evidence from the Weatherization Assistance Program." AEA RCT Registry. January 27. http://www.socialscienceregistry.org/trials/416/history/3446.
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Experimental Details
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
Take up of free energy audits, changes in energy consumption, greenhouse gases abated, difference between predicted energy savings and actual energy savings.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
We follow a randomized encouragement design to encourage treatment group households eligible for the Federal Weatherization Assistance Program (WAP) in Michigan. Since 1976 WAP has been helping low-income households manage their energy costs. Participating households receive free energy audits and several thousand dollars worth of free energy-efficiency retrofits.

The encouragements for treated households - carried out by a canvassing firm- include a combination of house visits, phone calls and in-person follow up appointments that provide the treated households with additional information about the WAP program and help them with the application process. Control group household are not encouraged in any fashion.
Experimental Design Details
Randomization Method
Randomization done in an office by a computer.
Randomization Unit
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
34,110 Households
Sample size: planned number of observations
34,110 households
Sample size (or number of clusters) by treatment arms
8,645 households encouraged, 25,465 households control
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
MIT Committee on the Use of Humans as Experimental Subjects
IRB Approval Date
IRB Approval Number
Protocol # o 1107004576
IRB Name
UC Berkeley Committee for Protection of Human Subjects
IRB Approval Date
IRB Approval Number
Post Trial Information
Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports, Papers & Other Materials
Relevant Paper(s)