Supermarkets are among the most energy intensive commercial buildings and they consume high amounts of refrigerant, thus causing significant environmental concern. Supermarkets therefore make up important targets for energy efficiency measures, one of which being heat recovery from refrigeration systems, particularly suitable for the environmentally friendly refrigerant CO<inf>2</inf>. In this work, four Swedish supermarket case studies are analyzed from a techno-economic perspective. All studied supermarkets have CO<inf>2</inf> booster systems with heat recovery and their technical efficiency are evaluated, as well as already accomplished economic savings. This study estimates the studied supermarkets are currently saving 600–6,100 € annually, which corresponds to 4–12 % of the energy costs for refrigeration and heating. Higher annual economic savings of 2,400–37,100 € (14–42 %) could be achieved if the refrigeration systems were instead controlled to cover all the heating demands in the supermarkets, or savings of 5,400–35,800 € (24–58 %) if also selling a surplus to nearby consumers. The heat recovery capacity and efficiency are parametrically explored, revealing the importance of designing systems for transcritical discharge pressures and low heating system return temperatures. The study also investigates the impact of price ratios of electricity and heat, demonstrating that recovering heat for internal use is a robust strategy under wide ranges of energy prices, while exporting surplus heat is more sensitive. Ultimately, this work shows that heat recovery solutions can significantly decrease energy costs in supermarket buildings under varying market conditions for electricity and heat, but the potential is yet to be fully realized in practice.