In a residential building in Alicante, Spain, an old and defective booster set, gives problems related to uneven pressure, low energy efficiency and noise. The solution? To install 2 KCV booster set with VFD inside the technical machine room: together with water tanks and boiler, this system perfectly satisfies the needs of the building. The 2KCV are equipped with electronics, specifically with one Active Driver Plus each, a Variable Frequency Drive, which keeps the pressure constant no matter the changing in the flow. This system ensures high energy efficiency and a longer life not only of the pump. Moreover, being the VFD water cooled, the system is also quite silent.