KUALA LUMPUR – In March, a few weeks after the war in Iran began jolting energy markets, Heidi Mendoza had solar panels installed on the roof of her three-storey house in Marikina, Philippines, from where she teaches financial literacy classes online.

“I got scared that we might lose electricity,” she said.

In May, Ming Kuang Chai, an architect in Kuala Lumpur, Malaysia, made a similar addition to his home.

“The Iran war, and the fact that I drive an electric car, pushed me to install the panels quickly to manage my living costs,” he said.

Adiana Julia hopes to add her parents’ house in Yogyakarta, Indonesia, to the solar-powered ranks early next year. “It’s better if we can find ways to reduce our dependence on the grid,” she said.

This shift is occurring in many parts of South-east Asia, a region whose energy sector is heavily reliant on oil imported via the Strait of Hormuz, which has been effectively closed since the war began.

The United States and Iran have announced a preliminary agreement to end the war and the strait may reopen soon. But the economic fallout from the conflict will last much longer, and in some cases may change consumer behavior for good.

Days after US-Israeli strikes on Iran started the war on Feb 28, the Philippines declared a nat...