Members of households lacking ACs with a heating function warmed themselves using electric blankets and/or oil heaters. In Long An, the corresponding period of AC use in light-use households was two to six months (March–August), but heavy-use households used their AC all year round. Also, the period of use tended to be longer in households with higher incomes. Fig. 3 Daily usage patterns of air conditioning for cooling by households in Hanoi. To understand more about the daily use of ACs, we asked each household to tell us who switched the AC on or off and how many hours they used the AC in each room. In Hanoi, eight households said that they used the AC while they slept (10 pm to 6 am). In Hanoi, children/grandchildren tended to use ACs for longer hours than did their parents (Fig. 3); the average daily usage time for children/grandchildren was 8.1 h, whereas that for their parents it was 5.3 h. In Long An, four out of six households also said that they used the AC while they slept and the period of usage was one to two hours earlier than that in Hanoi (i.e., 8 pm to 5 am). Regarding the temperature setting, 12 households said that they used a setting of 25°C–26°C, but some households used a setting 2°C–3°C higher or lower. It should be noted that older family members (grandparents) reported simply turning off the AC rather than adjusting the temperature because they could not read the English on the remote control for the AC unit, whereas the younger family members (parents in their 30s and 40s and their children) reported being able to read the English and understand how to control the AC. In response to the multiple-choice question, “What do you usually do to reduce electricity consumption when using the AC unit to cool a room?” most people in Hanoi chose “close windows/doors” followed by “limit the time/hours of use,” “clean the filter” and “do not turn on/off frequently” (Fig. 4). In Long An, most people chose “clean the filter” and “close windows/doors.” No one in either location chose “set air flow direction to horizontal.” Only one respondent in Long An chose “do other things,” which was to use an energy-saving mode. Regarding simultaneous use of a fan and AC, more households in Hanoi than in Long An said that they used both at the same time. Household Survey on Air Conditioner Use and Energy Consumption in Vietnam Regarding alternative methods of cooling, in Hanoi most people chose “open a window and let the wind in” and “do other things” (e.g., use a hand fan), followed by “have a cold drink,” “take a shower” and “go to a public space, shopping mall, cafe, etc.” (Fig. 5). In Long An, most people chose “have a cold drink,” “take a shower,” “open a window and let the wind in” and “sprinkle water,” meaning sprinkling water over the roads and pavement to lower the temperature via evaporation. No one chose “go to a public space, shopping mall, cafe, etc.” Due to the increased ownership of electric home appliances, electricity consumption by low-income households in urban areas and high- and middle-income households in rural areas of Hanoi had reached about 160–280 kWh per month (300–500 thousand VND; 14–23 and USD). Electricity middle-income and high-income households in rural areas in Hanoi had reached 330–670 kWh per month (600–1200 thousand VND; 27–55 USD), approximately twice that of the other groups. In Hanoi, monthly electricity consumption data were obtained from monthly electricity bills provided by several respondents. The electricity consumption of the households with ACs was highest summer (May–October) followed by spring (March–April) and winter (November– December) was the lowest season. In contrast, the electricity consumption of the households without ACs remained almost the same throughout the year. In rural areas of Hanoi, electricity consumption was highest in summer followed by winter and spring. Electricity consumption in rural areas of Hanoi was highest in winter when they turned heaters on for their livestock. In Long An, the electricity consumption of the low- and middle-income households without ACs in urban areas and low- and middle-income households in rural areas without ACs was a maximum of 140 kWh per month (250,000 VND; 11 USD). In contrast, the electricity consumption of middle-income households with ACs in urban areas and high-income households with ACs in rural areas was about 200 kWh per month (400,000 VND; 18 USD). The electricity consumption of high-income households with ACs in urban areas reached 1,000 kWh per month (2 million VND; 91 USD). In response to a question about the household’s intention to save energy, 80% of the respondents in Hanoi and 100% of the respondents in Long An said that they tried to save energy, and almost all of these respondents chose “economic reasons” as the trigger for wanting to save energy. With regard to energy-saving labels on electric appliances, the majority of respondents said that they did not remember seeing the labels, which suggests consumption in households (January–February); of urban high- areas in autumn 81 3.5 Alternative Methods of Cooling 3.6 Energy Saving
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