Runaway electrons (RE) can carry a significant part of the pre-disruptive plasma energy. If they strike the plasma-facing components (PFC), they deposit their energy in the form of high heat loads, which can lead to serious damage [1]. To study the RE heat loads on the most affected PFC (LFS limiter) in reaction to various mitigation strategies, a new diagnostic - a calorimetry probe - was developed at the COMPASS tokamak [2]. The temperature measurements of the graphite head before, during, and after a discharge were used for the identification of plasma and RE impacts. From the temperature increase, the total deposited energy was estimated. Using the surface temperature measurements by an IR camera, it was also possible to estimate the incident heat loads. A unique experimental scenario [3] allowed to study the effects of various mitigation strategies and RE control techniques, such as impurity injection and the RE beam position control. The results of these measurements will be presented in this contribution. The maximum energy deposited to the probe was (15 ± 1) kJ during a discharge with an additional acceleration by a positive loop voltage. Positive effects of lowering the deposited energy were observed mainly after injection of neon and deuterium by the secondary gas puff into the RE beam. Lower heat loads were also observed during discharges with an active radial position control of the RE beam. [1] J Mlynar et al, Plasma Phys. Control. Fusion 61, 014010 (2019) [2] R Panek et al, Plasma Phys. Control. Fusion 58, 014015 (2016) [3] O. Ficker et al, Nucl. Fusion 59, 096036 (2019)