It is baking hot in Portofino, but the atmosphere has turned decidedly chilly among residents of the exclusive Italian coastal village since a crackdown was imposed on air-conditioning units. With a year-round population of just 379, Portofino has emerged as Italy’s wealthiest municipality and is well known for being a magnet for the rich and famous. Madonna arrived on Sunday, reportedly for a party hosted by the fashion designers Dolce & Gabbana, but the talk of the village has been the hunt by local police for air conditioners illegally installed by residents seeking respite from the stifling heat. Portofino has been part of a regional national park since 1935, and up until a few years ago, the installation of AC units on its pastel-coloured buildings was entirely banned. As summers became hotter, the rules were loosened to allow use of the appliances, so long as the homeowner asked permission and ensured that the units were discreetly placed and did not sully Portofino’s natural beauty. Police have been scouring the narrow streets for unauthorised units poking out over the terraces of the village’s homes. There were reports of 22 illegally installed units spotted on various rooftops and terraces between January and May, and a further 15 since June as temperatures soared. Matteo Viacava, the mayor of Portofino, denied reports in the Italian press that police had deployed drones as part of their investigation. “It all began last winter when someone put in an air conditioning unit that covered a big part of a very narrow street,” he told the Guardian. “The summers have been getting much hotter and July and August have been sweltering and very humid. It’s not that we want people to suffer and have their sleep disrupted by the heat … We all depend on AC now. But Portofino is located in a regional park and there are rules that need to be respected.” As the intrigue heated up along with the temperature, Corriere della Sera reported a “vendetta” among residents involving tit-for-tat denunciations between neighbours. Some culprits have attempted to hide their AC unit or disguise the appliance by painting it to blend in with the local surroundings. In some cases, people have reportedly accepted an invitation into the home of a neighbour, only to secretly take a photo of a unit that they have then passed on to police. Those who flout the rules risk fines of as much as €43,000 (£36,800) if prosecuted in court, although Viacava said most cases to date had been resolved and that the goal was not to fine people. “We just want to ensure that the constraints are respected and beauty of Portofino is maintained,” he said. “They need to be put in places that are not visible. Slowly, slowly, we are getting it all in order.” A police officer in Porfofino declined to reveal details of the ongoing checks. Earlier this summer, Portofino was sealed off to host 800 guests at a pre-wedding party for the Indian billionaires Anant Ambani and Radhika Merchant, costing a reported €139m. Italy has been engulfed by consecutive heatwaves since around the middle of June. Some central and southern areas are expected to record temperatures of above 40C in the coming days. On Monday, the health ministry placed 17 cities on red alert, meaning it is expected that even healthy people could be at risk from the heat. People living in or visiting places on red alert are advised to avoid direct sunlight between 11am and 6pm. The demand for AC in Italy has shot up in recent years. A report in 2022 by Istat, the national statistics agency, found that half of all Italian households had an AC unit.