Everything you need to know about producing hot water with a heat pump

Faced with soaring prices of fossil fuels , the choice of the heat pump for the renovation of its heating system has become obvious for many households. Efficient and running on renewable energy , the air/water heat pump also has the capacity, depending on the model, to provide two functions for the daily comfort of your home: heating and production of domestic hot water . 2-in-1 equipment that allows you to generate real savings on your energy bill while improving your well-being at home!

Operation of the air/water heat pump for heating

The air/water heat pump is made up of two elements, an outdoor unit, and an indoor module, and operates on the principle of aerothermal energy . In other words, if electricity is necessary for its operation, this heating system is powered by renewable energy, the calories present in the air, to produce heat.

The two units are connected to each other in a closed circuit, for step-by-step operation taking place as follows:

  1. The outdoor unit takes the calories to present naturally in the air, a free energy, and transmits them to the refrigerant which redirects them to the indoor unit.
  2. The liquid changes to gaseous state thanks to the compressor and increases the temperature of the heating water.
  3. The heat is released, via the condenser, to be diffused in the central heating circuit, made up of various heat emitters such as radiators or underfloor heating .
  4. The gas then drops in temperature as it passes through the expander and restarts the cycle to continue heat production.

In the case of a heat pump producing domestic hot water (DHW), the indoor unit is more massive and includes a water storage tank, with variable volume according to the household’s needs (from 170 to 300 L on average).

The calories then circulate in a serpentine tube placed inside the hot water tank and delivering the heat produced by the heat pump. This is to raise the temperature several times a day and prevent the proliferation of bacteria.

The installation of a mixed heat pump producing heating and hot water is ideal as part of an energy renovation project for your home . In this way, you reduce your electricity consumption while promoting the use of renewable energy to ensure your daily comfort.

For hot water to be called “sanitary”, it must be heated to 60°C for 30 minutes on average, before reducing the temperature to between 50 and 55°C to supply your distribution circuit. This precaution helps protect your home from the risk of legionellosis.

hot water with a heat pump

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How to have domestic hot water with a heat pump?

Several configurations are possible to produce domestic hot water with your heat pump. Indeed, in a renovation project including heating for this function, different criteria must be taken into account and influence the choice of your equipment.

Hot water production integrated into the heat pump

This 2-in-1 solution is the most practical and the easiest to install . Indeed, your air/water heat pump already has the tank needed to store the water in the indoor unit. Several liter capacities are offered to meet the hot water needs of your home.

This configuration then fully benefits from the advantages of the coefficient of performance (COP) of the heat pump. Thus, the rise in temperature of the stored water is very rapid. This is particularly noticeable during the summer season. Even if your heat pump must operate without having to supply your heating, it is used in the best thermal conditions and therefore only takes a short time to heat your water tank. Thus, you can save up to 70% on your energy bill, for the production of your DHW .

Finally, by choosing a 2-in-1 heat pump, you also save space in your home, by no longer having to use the hot water tank in addition to your old boiler. The price of a mixed heat pump fluctuates between $10,000 and $13,000 , depending on the brands of heat pumps and the capacity of the integrated tank.

You should know that the production of domestic hot water with an electric water heater alone represents between 15 and 30% of your electricity bill for the year. The use, therefore, of a heat pump offering this solution, in addition to heating, is a good compromise to greatly reduce your energy consumption!

The heat pump with remote hot water production

This configuration applies if you do not have sufficient ceiling height to place your mixed indoor unit in the chosen room. Indeed, if the models are designed to be compact, the height of the module can reach 2 m in the case of large volume storage tanks.

A tank is associated with your heat pump and depends on it to operate. You can thus choose the capacity that best suits your needs and take advantage of the performance of your heat pump for a rapid rise in temperature of your DHW . Even if your equipment operates throughout the year, to produce hot water, you minimize your energy consumption thanks to its coefficient of performance which is ultra-efficient, due to optimal climatic conditions. These allow your appliance to heat your water tank, on average, in 2 hours.

Finally, the installation of an air/water heat pump with remote tank remains quite simple and can be done quickly. Its price is generally similar to that of a mixed heat pump.

The thermodynamic water heater, for independent production

The thermodynamic water heater (CET) acts autonomously and does not depend on your heat pump to produce domestic hot water. It works according to the same principles by itself having a lower power compressor which transforms the calories taken from the air as a heat source in order to heat your storage tank via a coil. It also has an electric back-up, if the weather conditions are too harsh to achieve the correct heating power.

This model is ideal in the case of a project to replace an electric water heater , or if you do not have the necessary surface to install a balloon near your heating system. In this way, you heat your water in an environmentally responsible way while saving energy. However, its operation is more restricted than that of a mixed heat pump, which means that the production of hot water takes longer, between 5 and 7 hours, depending on the capacity of the tank. However, this device has a valuable advantage : it consumes 70% less energy compared to a conventional electric water heater !

Note, finally, that investing in a thermodynamic water heater represents an average budget of around $3,000 , depending on the models on the market. Since heat pumps providing only heating are less expensive than mixed heat pumps, the overall amount of two devices remains relatively similar to a mixed heat pump. In addition, this equipment is eligible for financial aid, subject to income conditions.

Cumulus, 2-in-1 heat pump, remote balloon or CET: what to choose?

In an energy renovation project for your home, the choice between these different pieces of equipment to provide you with hot water can be complex. The main objective of this approach is to meet two prerequisites: reduce your impact on the environment and the amount of your energy bills.

Thus, if you want to replace an old gas or oil boiler with a heat pump, the choice of an electric cumulus is not the most judicious. The same applies if your old DHW production equipment is located in a different room from your heating system. Even with a recent model, you still consume a lot of electricity because this equipment requires long hours of heating so that the contents of the tank are at the right temperature. Moreover, its energy-intensive aspect means that it is not eligible for financial aid from the State .

The thermodynamic water heater, operating on the principle of aerothermal energy, is preferred if your heating system runs on electricity, or if you have an air/air type heat pump . The latter, unlike its counterpart the air/water heat pump, cannot in fact produce DHW.

If you choose an air/water heat pump for your heating, the alternative of the 2-in-1 model or the heat pump in heating alone with a remote tank is an excellent compromise. Indeed, you benefit from a more efficient coefficient of performance. Your domestic hot water is quickly up to temperature and the different capacities in liters offered allow you to ensure optimal comfort in your home, depending on the number of occupants and the number of water points to be supplied (bath, shower, sink, etc.).

Moreover, if this investment seems significant to you at first sight, various financial aids for the purchase of a heat pump are proposed. Do not hesitate to call on a professional to find the equipment best suited to your situation.

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