An apparatus for controlling conditions in a plant cultivation facility is provided, said apparatus comprising at least: a lighting system arranged in connection with plants present in an environmentally sealable and closable cultivation facility; a hydronic cooling arrangement for lowering or impeding the rise of temperature in the cultivation facility, said cooling arrangement comprising a cooling manifold present in connection with plants in the cultivation facility and a heat recovery arrangement for utilizing excess heat generated in the cultivation facility, said heat recovery arrangement including a heat storing system. The apparatus has its heat recovery arrangement including one or more condenser dryers/coolers for collecting water and/or heat absorbed in the indoor air of a cultivation facility and a heat pump assembly for transferring the heat, accumulated in the heat storing system by way of the cooling arrangement's circulation water and/or the condenser dryer's/cooler's circulation water, into a secondary circuit independent, with respect to its one or more water circulation loops.