Energy efficiency and economy with hybrid control: District heating and heat pumps in multi-family houses

In response to volatile electricity markets and recent record increases in district heating prices in Sweden, smart control strategies for heating systems have become cost-effective solutions to reduce energy costs. By shifting electricity use for space heating and domestic hot water (DHW) to hours with lower prices, significant savings can be achieved. Historically, district heating has been a low-cost standard in Sweden, but recent price surges have led to the emergence of hybrid systems combining district heating with heat pumps, controlled by smart systems. This study evaluates five multi-family buildings renovated between 2022 and 2024. Systems using smart control for space heating and DHW were assessed, focusing on load shifting based on electricity prices. Investments in exhaust air heat pumps led to total energy reductions of 15 to 32 %, and district heating use decreased by 28 to 48 %. Additionally, billing power, which affects district heating tariffs, was reduced in most cases. Case Building 1 exhibited the highest reduction of 33 kW, translating to 2,768 EUR in tariff savings in 2023. Case Building 3 achieved savings of 1,880 EUR in 2023 and 1,557 EUR in 2024, with smaller reductions observed in other cases. It is essential to comprehend local pricing models to schedule heating during off-peak times. The current investigation has provided valuable real-world performance data on smart controlled hybrid systems under the new Swedish tariff structures. This data highlights the effectiveness of these systems in reducing energy costs, showcasing their potential for widespread adoption in regions with similar tariff models.