From the moment the choice turns towards a heat pump system, the heat pump in question is very easily reversible and the need for heating can be satisfied as to the need for cooling. Reading
High Performance HVAC Heating and Cooling you can get more help to choose the best one.
First case: The need for air conditioning is paramount
This is undoubtedly the case for a waiting room at the doctor's office, or a dining room for a particular retirement home. The calculation must actually be done on the mass of air conditioning needs: the sum of the internal needs (number of occupants, releases of electrical equipment, lighting, TV, ...) and external needs (sunshine, thermal insulation, treatment of the outside air). Air conditioning thus calculated and dimensioned can be used for heating, using the reversibility of the cycle. It is the same air conditioning equipment that becomes a heat pump. The COPthe efficiency is between 2.5 and 3.8 depending on the quality of the material and its ability to heat even when the outside temperatures are negative. In this type of calculation based on summer loads, the heating capacity of the air conditioner is generally large and sufficient to heat the room in question.
Second case: the need for heating is paramount, cooling is a result
This should be the most common case for the habitat, which in itself has to be better and better insulated thermally and protected from sunshine.
Type of installation 1: the thermal installation will be equipped, if the need for cooling is a demand for comfort, by aso-called reversible air/water heat pump, producing hot in winter and cold in summer, hot water going through a heated and refreshing floor. The main parts to consider not to increase in addition the power of the heat pump to size in winter mode, are the living room and bedrooms. A water/water heat pump with a higher COP efficiency is also a very good energy source. The installation is then called geothermal by water/water PAC, the latter being reversible and producing "pumped" cold in the environment, ground, or external well.
Installation type 2: an air/water heat pump supplies heating and cooling to the main living rooms such as living rooms and bedrooms. Other rooms such as kitchens, bathrooms, ... are only equipped with radiators or radiant panels, mostly electric. This system is more economical than the previous one because of the simple diffusion by air. Nevertheless, the comfort is less: air movements and dust entrainment, noise level of the indoor unit, ... Note that quality air conditioners can counteract this type of inconvenience with a very high level of filtration and noise levels. extremely low.
Third case: the system is global, it also ensures the production of domestic hot water in addition to heating and air conditioning
This type of installation uses the economic operation of the heat pump which produces the heating and, in addition, the production of domestic hot water using what is its strength, that is to say its COP, Coefficient of Performance, which can go up to 4.
The domestic hot water is thus produced with an energy efficiency of the most interesting compared to a typical production hot water with a conventional electric balloon (efficiency of 1). In addition, the latest innovations in this area allow you to connect if you want a solar kit allowing you to benefit from free calories through these solar thermal panels.
In this case, the thermal system is global and complete and the air conditioning function is no longer main. The heat pump is certainly reversible, it brings its air conditioning function but above all its energy advantage in heating mode.
Heating or air conditioning?
The question is more oriented towards a priority response to heating, cooling being a complementary comfort and consumption, in addition, penalizing the energy balance of the house. The energy classification from A to G now takes into account the overall consumption of heating, hot water, and air conditioning. In addition, remember that the thermal regulation in the new and in some heavy rehabilitations in the existing integrates the needs of air conditioning to limit and find limiting measures such as masks, screens, external blinds.