175 households were recruited through door-to-door contact; they were randomly assigned into five groups. The first group was prompted by a letter and phone call to watch the TV programme. In addition to these prompts, the second group received a weekly form related to household comfort issues (like clothing worn in the home). The third group received the prompts, the weekly form, as well as a home visit, which explained conservation strategies in a more detailed way. A fourth group, which received only the weekly form, served as a control group. Finally, another control group did not receive any forms, but had their electricity meters read. Electricity meters were read three times per week during the baseline and five-week intervention phases, and once per week during the first follow-up, booster, and second follow-up phases. Gas meters were read once per week and only during the booster phase.

A 12-item multiple-choice questionnaire was distributed to measure how well participants were informed about energy conservation issues before and after viewing the TV programme. A strategy questionnaire, administered during the first follow-up phase, included 11 strategies presented during the TV programme to assess what kind of energy substitution strategies were used before and after the programme.

Short-term increase in knowledge about the energy issues and substitution strategies was observed (there was no test for long-term impacts). Whereas before viewing the programme, participants were correct 44% of the time when answering questions related to energy use, they were correct about 74% the time after viewing.

The following new behavioural strategies were adopted after the viewing of the programme:

• Opening the house at night: 46%
• Turning the air conditioning off at night or 82F (27.7C) before sleep: 44.6%
• Using natural ventilation: 40.5%
• Using air conditioning in the afternoon only if it is very hot and setting it at 78F(25.5C): 35.1%
• Using fans: 33.8%
• Closing the house down in the mornings: 29.8%
• Turning the air conditioning off to 82F (27.7C) when gone for 2 or more hours: 29.7%
• Setting the air conditioning thermostat at 78F (25.5C) in the evening: 25.7%
• Turning the air conditioning off in the morning: 24.3%
• Setting the water heater at 130F (54.4C): 20.3%
• Insulating the water heater: 8.1%

Overall Results:

Exposure to the TV programme, and not personal contact, was the most important element. In fact, contact with participants was not beneficial. The first follow-up indicated that the participants who viewed the programme, but who were not contacted by the project (no phone call, no home visit), reduced their energy use by 17%, while the participants who were contacted reduced their energy use by only 6%.

When the participants were employing energy substitution techniques, the temperature, humidity, level of comfort and typical clothing worn inside of the house did not change.

The results show that even a single viewing of the programme resulted in the adoption of some simple, no-cost cooling strategies that yielded overall electricity savings of 10% (yielding a 23% savings on electricity used for cooling). However, the following summer, residents returned to their pre-programme energy usage. One explanation is that the participants' low-budget share for energy moderated the effectiveness of the media intervention.

‘Personal reasons', such as saving money were found to be more persuasive than ‘environmental protection' reasons for energy conservation. It cost about US$1 per home to encourage viewing via phone and written prompts.

Tools of Change website.