Many people consider converting the system in their house or condominium. Here's everything you need to know about hybrid systems.

Heat pumps are devices for taking (free renewable) energy from the environment, such as air, groundwater or underground heat, in order to produce domestic hot water and provide air conditioning for both apartments and commercial and industrial buildings. The advantages of heat pumps in terms of energy savings are undeniable, although there are certain situations in which there can be operating constraints. 
While very efficient and environmentally friendly, it can be necessary, when the weather is especially cold, to combine the heat pump with a boiler. The solution is to choose a hybrid system that combines the heat pump with a condensing boiler which can make its contribution as and when needed.

The operating logic of the heat pump

This technology consists of four separate devices, namely the compressor, condenser, expansion valve and evaporator, which allow a particular refrigerant to transfer heat.

During its evaporation, the fluid absorbs energy from the heat source (the outside air, ed.) and decreases in volume as it flows through the compressor, causing an increase in temperature and pressure.

In the condenser, the gas returns to a liquid state and transfers its stored heat to the domestic heating or hot water system, and then enters the expansion valve, which reduces its pressure and returns it to the evaporator. Thanks to the heat pump, no fossil fuels are consumed since the primary source of energy is renewable, but the process still requires the use of electricity.

The operating logic of the condensing boiler

The condensing boiler is the main system for domestic heating and the production of domestic hot water that is extremely energy efficient and consumes very little gas.

Its great efficiency is attributable to the recovery of heat from combustion smoke, part of which can be used without having to resort to new raw material, and as a result the boiler is more environmentally friendly and less polluting.

The condensing boiler also emits fewer emissions into the environment due to the presence of special pre-mix burners. Another plus of this heating system is the ability to modulate the power output of the system according to the specific needs of each individual building, and its operation is not affected by the variation in outdoor temperature (as is the case with the heat pump, ed.).

The hybrid system: the perfect combination of two configurations

We have seen how a heat pump works and what a condensing boiler is like. But how can these two devices be combined to create a system that ensures maximum efficiency and optimal living comfort in every season?

The primary heat generator in a hybrid system tends to be the heat pump, which is sized to cover up to 80 percent of the home's annual heat load (the thermal energy that is lost to the outside environment, ed.). In this way, free renewable energy is put to full use and the condensing boiler “covers” the remaining 20% of the heat load.

It is also an ideal solution in the case of renovations because it can be combined with the conventional radiators normally found in houses that are to be upgraded.

Here are a few examples based on meteorological conditions. In a hybrid system, if the outdoor temperature is not too low, only the heat pump is used, leaving the boiler off and therefore avoiding the consumption of fossil fuels. As the weather gets colder, the heat pump may not provide the required heat energy input to heat rooms and produce domestic hot water. Consequently, in case of excessively cold temperatures, the two systems will first work in parallel and then the boiler runs by itself at full load.

Clivet: hybrid systems for every need

Ideal for renovations, Clivet's hybrid systems offer seamless integration between the best heat pumps on the market and high-efficiency condensing boilers, while also providing maximum versatility in terms of installation (wall, floor and uncased). All the products, whether split or single-unit, are available in a wide range of power ratings, have an aesthetic design that makes them suitable for any room in the house, and come with an app for remote control.


SPHERA EVO 2.0 EASYHybrid is the hybrid system developed by Clivet that combines a wall-mounted air-water heat pump with a 24- or 34-kW condensing boiler that can instantly produce domestic hot water. This product ensures full compatibility with a radiator system, since it can produce water with a maximum temperature of 80 °C, and recently won the KLIMAHOUSE PRIZE as a product capable of adapting to the needs of the market.

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