Energy programmes often treat "the household" as a single type: give people information and an incentive, and they will respond the same way. My doctoral research in Tonga suggests otherwise. Grouping 102 households on Tongatapu by their cooking appliances and routines, using a two-step clustering method adapted from earlier New Zealand work by Lawson and Williams (2012), revealed four distinct cooking energy cultures. They were built from cooking data, but they reflect motivations, values and constraints that shape energy use across the whole home.

Energy-efficient households are working adults with stable employment and the means to cover their energy costs comfortably. They understand energy efficiency and have built habits around it. They had the lowest average monthly spending on gas, transport and electricity of any group, mostly cook with gas because they see it as convenient and cost-effective, and choose refrigerators over larger deep freezers. They are already convinced. The opportunity is to use them as visible examples and give them access to better products.

Energy Economic households are middle-aged families on moderate incomes who put family expenses first while still meeting religious and social obligations. They rely on old and inefficient stoves and deep freezers because they cannot afford to replace them, and use firewood stoves and the 'umu to keep gas and electricity bills down. They used the least energy of any group and are inventive about it, wrapping food in foil to hold heat and keeping boiled water in insulated flasks. They are careful without knowing much about efficiency as a concept. What holds them back is the cost of better equipment, not their attitude.

Energy-Altruistic households are financially stable and put social and religious obligations above everything else. They are respected for their generosity in providing food and donations for church and community events, and they own larger appliances to cater for big gatherings. Their energy use is high. They recognise that efficiency matters but it is not their priority, and their commitments can lead to debt that relatives abroad often help to cover. Saving money on electricity will not persuade them. Efficient ways of cooking for large events might.

Energy Extravagant households are middle-aged, with higher education and income, and know about efficient appliances. They choose comfort and convenience instead, partly from a desire for recognition from colleagues, and prefer electric stoves for their consistent performance. For them, efficiency competes with status, so it has to be presented as something that adds to status rather than takes from it.

One programme cannot reach all four. Information campaigns suit the first group, help with upfront costs suits the second, and the third and fourth respond to community and social standing more than price. The thesis points to some options that cut across groups. With government support, community cooking hubs could move large-scale cooking out of individual homes into efficient shared spaces that also serve as places to learn about and demonstrate efficient technologies. Community and church leaders, trusted far more than government messaging, can champion efficiency with their congregations.

The clusters in Tonga differed from those found in New Zealand, although there were some similarities. That is the wider lesson for the Pacific: the approach transfers across island nations with similar social and economic structures, but each country needs to identify its own energy cultures rather than borrow someone else's.

Dr Kakau Foliaki, Director, Teulava Consultancy. Based on the PhD thesis "Energy cultures amongst Tongan households: implications for energy efficiency policy" (University of Otago, 2024).