Air conditioning systems and domestic heat pumps are both a type of heat pumps. While the air conditioning systems work only on one mode, which is the cooling mode, the domestic heat pumps, can work both in cooling and heating modes. In fact, during cooling mode, there is not a big difference between the two types. Technically, air conditioning systems, are heat pumps that work in reverse.
The main characteristic that makes the difference between a heat pump and an AC unit is the operation mode. AC units operate only on cooling mode, while heat pumps can operate on both cooling and heating modes.
HOW DOES A HEAT PUMP WORK?
So, when we talk about heat pumps, it could be either a domestic heat pump or an AC unit. As previously explained, the difference between the two units, is the operation mode. Briefly, a heat pump contains two important zones: a cooling zone – (Evaporator) where the heat is extracted from the ambient, thus cooling down a desired space, and a heating zone – (Condenser) where heat is rejected to the ambient, thus heating up the desired space, like in the figure below.
WHAT ARE THE INDOOR AND OUTDOOR UNITS OF A HEAT PUMP?
Now, both the domestic heat pump and the AC units, have a component that needs to be installed inside the house, and one that needs to be installed outside. For AC units, the outdoor component is the “condenser” or the “heating zone” part. The way the AC works, is that it takes the heat inside your house (via a cooling agent named refrigerant), and it rejects it to the ambient (via the outdoor unit). For domestic heat pumps that work on cooling mode, the operation is the same. However, it can be run on heating mode, via a reverse valve inside the compressor. The compressor is used to increase the pressure of the cooling agent, to increase its temperature, so that more energy can be released in the “heating zone” of your heat pump unit.
SHOULD I GET A HEAT PUMP OR AN AC UNIT?
The answer to this question is dependent, of course, of where you live. If you live in a warm climate, where no extra heating is required throughout the year, then an AC unit is more desirable because it has lower installation and maintenance costs. However, if you live in a relative cold climate, then a domestic heat pump is more desirable. It is expected to have higher operational costs with a domestic heat pump, since its going to be used throughout the year. This will decrease to a certain degree the lifecycle of your pump. At very low temperatures, the efficiency of a heat pump starts to drop drastically, so for those who live in very cold climates, it is recommended to have an additional way of heating to go along your heat pump. One cheap solution is of course a furnace. If electricity is cheap in your country (for example Norway, where 96% of their electricity comes from hydro-power), then you could consider installing a water-based floor heating.