Energy Retrofit Subsidies for Multi-Family Apartment Buildings in Finland: Lessons Learned and Best Practices

This study analyzes the renovation measures implemented in Finland for multi-family apartment buildings using ARA renovation subsidies. The measured energy data was used to calibrate the energy simulation model of the most typical renovated buildings of the 70s of the 20th century. For reference buildings, a comprehensive renovation package was adopted to evaluate the performance of the ARA grant. It has been noted that the official Energy Performance Certificate (EPC) is almost 2 times overestimated before transforming energy use and energy savings. It is important to note that in the calculated EPCs, the EP value after the retrofit is higher than the EP value before the retrofit, based on the measured energy use.

The main reason for the miscalculation of energy is the gross overestimation of the building's leakage rate and ventilation airflow rate. The retrofit program reduced the EP value by 8% to 27%, including lighting and appliances. The duration of electricity using district heating increased slightly, the curve was flat, but the peak electrical power of the ground source and exhaust air heat pumps increased by a factor of 6. Exhaust heat pumps, window replacement, and photovoltaics are the most efficient options, while the cost of additional insulated packaging is much higher than the cost of ARA support and monthly savings to cover bank loans; The need to improve the accuracy of EPCs in assessing energy performance to facilitate more effective financial support is important for any support plan to secure the necessary funding for renovations.