Why is the heat pump bivalent point so important?

Heat pumps are a green and very popular solution for heating homes and public buildings, providing energy efficiency and promoting sustainability. One of the key aspects to consider when selecting and designing a heat pump system is the so-called bivalent point. In the following article, we will try to explain why it is so important and how it affects the performance of the entire heating system. Check it out!

Bivalent point - what is it?

The bivalent point is the outdoor temperature at which the capacity of the heat pump becomes insufficient to meet the total heat demand of the building. In other words, it is the point at which the heat pump ceases to be the only source of heat and the system begins to need support from an additional source.

Why is the bivalent point important?

  1. Optimisation of operating costs

The bivalent point has a direct impact on the economic efficiency of the heat pump. If the bivalent point is set correctly, the system can maximise the use of the heat pump, which is usually cheaper to operate than traditional heating systems. If the point is set too high, heating costs can increase because auxiliary heat sources will be used more frequently.

  1. Ensuring thermal comfort

During periods of extremely low temperatures, when the heat pump's output drops, the system must be able to quickly switch to an alternative heat source to maintain an adequate indoor temperature. A correctly determined bivalent point ensures that this switchover occurs smoothly before the internal temperature starts to fall below a comfortable level.

  1. Increasing the sustainability of the system

Heating systems operating within the limits of their maximum efficiency are usually less likely to fail. By backing up the heat pump with another heat source under extreme conditions, the whole system can operate more efficiently and for longer.

How do you determine the bivalent point?

The bivalent point is usually determined by a number of factors, such as the climate of the region, the insulation of the building, as well as the specific heat demand. Determining the bivalent point for a heat pump is key to ensuring the energy and economic efficiency of the heating system. This process requires the analysis of several important factors that influence the optimal performance of the heat pump under different climatic conditions. Here are the four main steps to consider when determining the bivalent point:

  1. Regional climate analysis

The first step is to understand the typical range of temperatures the system will have to cope with. Regions with mild winters will have a different optimum bivalent point than areas with very harsh winters. Historical data on minimum temperatures can help determine how low the outdoor temperatures the heat pump should be able to operate effectively.

  1. Assessment of insulation and building performance

Good thermal insulation of a building significantly affects the efficiency of the heating system. Better insulated buildings require less energy for heating, which means that the heat pump can be effective at lower outdoor temperatures. In such cases, the bivalent point can be set at a lower outside temperature.

  1. Heat demand analysis

The next important step is to calculate the total heat demand of the building. This includes not only space heating, but also hot water needs. The higher the demand, the earlier it may be necessary to introduce an additional heat source.

  1. Heat pump efficiency

Different heat pump models have different performance characteristics depending on the outside temperature. The thermal efficiency of a heat pump usually decreases as the outside temperature drops. It is important to study the performance curves available in the technical specifications of the unit to understand at which temperatures the performance decreases.


The bivalent point in a heat pump system is key to ensuring the cost and energy efficiency of the heating system. By properly defining and using this point, the comfort of the building can be significantly improved, operating costs can be reduced and the life of the entire system can be extended. When selecting


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