27 Jun 2022

Differences Between AC and Heat Pumps. What Do I Need to Know?

When it comes to cooling systems for your home, do you know all the options available? Air conditioners are a well-known option, and you are likely already familiar with how they work. But during the last few years, heat pumps have been gaining popularity, and you may have heard of them, but not quite understand how they differ from air conditioners. Do they both function equally? What features do they provide?


In this article, we will try to brush away any doubts and answer some of the most common questions regarding heat pumps in contrast to air conditioners.

Differences Between Air Conditioners and Heat Pumps

Conventional air conditioners and heat pumps essentially work using the same technology. That is, by taking heat from one space and releasing it outside, leaving the indoor room cooler and more comfortable. What makes heat pumps different is that they can reverse this process and, in simple terms, can take heat from the outside and release it indoors, providing heating for our indoor spaces.

Air conditioning functions in a quite straightforward way: it uses a refrigerant that flows through a closed loop, evaporates and condenses continually to transfer heat. The indoor unit consists of an evaporator coil, while the outdoor unit consists of a condenser, a compressor, and a fan. The heat inside our homes is transferred through the coils and then dispersed outdoors through the exterior unit’s fan.

Regarding heat pumps, we can find different types, depending on the source they use, aerothermal heat pumps and geothermal heat pumps. Aerothermal heat pumps use air as their source and transfer heat from the surrounding air. On the other hand, geothermal heat pumps use heat from the ground.


In this article, we will be focusing on aerothermal or air source heat pumps. 


Air source heat pumps work much like conventional air conditioners, using a refrigerant that evaporates and condenses in a cyclic process to transfer heat from the inside to the outside. As a matter of fact, a heat pump generally has the same components as an air conditioner. But as we mentioned earlier, this process can be reversed, which is possible thanks to a reversing valve that changes the refrigerant’s direction through the coils. Heat pumps are able to collect heat from the outside, even during the colder months, and transfer it indoors to heat our home.


In the range of air source heat pumps, we can further distinguish another category, depending on how the heat is distributed into our home. As such, there are air-to-air heat pumps and air-to-water heat pumps. Here are their features:

  • Air-to-air heat pumps are functionally more similar to conventional air conditioners. We can find them in similar setups as air conditioners: split, cassette type, and console type. Air-to-air heat pumps transfer heat present in the air and release it in the form of cooled or heated air.

  • Air-to-water heat pumps transfer heat from the air into water through a piping system around the house. This type also allows domestic hot water to be stored and used for bathing, showering and domestic hot water. The indoor units of an air-to-water heat pump consist of radiators, radiant floors or fan coils, through which water circulates for heating and cooling.


Both conventional air conditioners and air source heat pumps are energy efficient, they both help contribute to humidity control and promote air circulation, creating a healthier environment in our homes. Both systems can have specialised filters incorporated in the indoor units to protect both the inside of the units and improve indoor air quality. If you want to learn more about how air conditioning can improve indoor air quality and keep allergens at bay, read our article here.



Advantages of Air Conditioners

Despite their similarities, when comparing conventional air conditioning to air source heat pumps, there are some advantages to take into account:

  • Air conditioners are specialised in cooling. As cooling experts, they are designed specifically for the purpose of cooling and so are more appropriate in places where temperatures are constantly warm. 
  • Air conditioners usually require less upfront cost to get installed than heat pumps. Although, of course, this depends on many factors, including cooling requirements, tonnage, location of the unit, and your home’s size. And although it will greatly vary depending on the home’s architecture; generally speaking, smaller homes benefit from lower installation costs.
  • Air conditioning systems can have a simpler installation than heat pumps; although, as mentioned above, this also depends on the type of air conditioner. Whether you will need ducting installed or not is also another aspect to factor in. Air conditioners come in a variety of setups to adapt to different spaces, from very small apartments to large multiple-room houses. It is possible to install multiple indoor units and only one outdoor unit, and there is a variety of styles for indoor units to choose from.

Air Conditioner Adapted to Different Spaces


Advantages of Air Source Heat Pumps

Aerothermal heat pumps offer great advantages when compared to air conditioners, which are related especially to the fact that heat pumps are two-way cooling and heating systems. Let’s take a look at these benefits:

  • A heat pump provides cooling and heating in one system. All heat pumps can be used for both cooling and heating, thanks to the reverse process we talked about above. But in the case of air-to-water systems, there is an added advantage, as they can also supply domestic hot water. It is ideal for those who want a three-in-one solution for all their HVAC needs.

  • It is a completely electric system; utility bills for heating and domestic hot water, in the case of air-to-water heat pumps, are all-electric, reducing the hassle of keeping up with different costs for each requirement.

  • As it uses clean, renewable energy, a heat pump has a lower carbon impact and is more environmentally friendly than combustion-based heating systems; such as boilers, furnaces and gas burners. In the same way, it does not contribute to greenhouse gas emissions, and it is safer for our homes, as there are no dangerous exhaust fumes to worry about.



AC or Heat Pump: Which One is Better?

As you have seen, both air conditioners and air source heat pumps have plenty of advantages, but which one is better? The answer is not as simple as you may expect, because it depends on your personal situation. Here are some factors that need to be taken into account to choose between a conventional air conditioner and a heat pump.

  • Installation
    Although both air conditioners and heat pumps are adaptable and versatile systems, your budget for initial installation can be a decisive factor depending on your home’s characteristics. Ducted and ductless options are possible for both air conditioners and air-to-air heat pumps. An air-to-water heat pump will need to incorporate radiators, radiant flooring or fan coils to function, which could indicate a significant home renovation, or could be an ideal solution if your house already has these elements installed.

  • Climate
    Do you live in a region with a moderate climate? Or do you experience extreme winter conditions? Even though heat pumps can efficiently heat an entire home, they don’t perform as well in below-freezing temperatures. When compared to combustion systems, heat pumps may need to run longer in extreme freezing temperatures to get to a comfortable indoor heating ambience. For this reason, they are excellent for more moderate climate zones. Although this does not mean that they can’t be used in freezing winter regions, they will simply need to be paired with another conventional heating system to back the heat pump up on extremely cold days for optimal heating. This dual type of heating system is known as hybrid heating and is also a much greener alternative to traditional combustion-only systems.

  • Cooling, heating and hot water requirements
    Location aside, what does your home already have installed? Does it require heating and cooling? Or maybe already have a heating system you’re happy with, and only need cooling? Depending on your answer to these questions, you can look either into air conditioners or heat pumps. Furthermore, if you require heating, and decide to opt for a heat pump, do you also want it to provide domestic hot water? Think about your household’s needs, and it will help settle the choice better.

  • Your home’s size and architecture
    Whether you live in a cosy open concept loft or in a multiple-room house with more than one floor, impacts a lot on the type of HVAC system you will need. Smaller homes can really benefit from simpler mini-split units. Meanwhile, large homes will require either multiple indoor units to be installed for each room, or radiant flooring in the case of air-to-water heat pumps. If you’re unsure about which is the best system for your home, let a trusted installer advise you based on your individual situation.



We hope to have shed some more light on the differences between conventional air conditioners and air source heat pumps. Whether it is for cooling or heating if you’d like to find which technology Hitachi Residential Air Conditioners offers for year-round comfort at home, click here to view our range of products.

ꟷ Hitachi Cooling & Heating Australia ꟷ
27 Jun 2022