Mon 30 May 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, and 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.


We can further distinguish another category in the range of air source heat pumps, 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: wall-mounted 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 the water through a piping system around the house. This type also allows domestic hot water to be stored and used for washing, bathing or showering. 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-to-air source heat pumps can have specialized filters incorporated in the indoor units to 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.



Air Conditioner Adapted to Different Spaces



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 specialized in cooling, so are more appropriate in places where temperatures are constantly warm and the heating function will not be useful.
  • 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.



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:

  • An air-to-air heat pump provides cooling and heating in one system thanks to the reverse process we talked about above. But in the case of air-to-water systems, they can also heat your rooms through radiators or underfloor heating, provide with refrigeration and even supply domestic hot water. It is ideal for those who want a all-in-one solution for their homes.
  • With heat pumps, no other source of fossil fuel is needed, resulting in a significant reduction in the monthly bill. The heat pump captures thermal energy from the environment, free of charge, consuming only electricity to operate the unit. For example, an aerothermal heat pump delivers 4 kW of thermal energy and consumes only 1 kW of electricity, capturing the remaining 3 kW from the environment for free. Performance will always depend on the unit and local ambient conditions. Learn more about the benefits of a fully electric cooling and heating system here.
  • In addition to using renewable energy sources, heat pumps contribute to reducing indirect CO2 emissions compared to other systems thanks to their efficient performance, 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? It is always necessary to choose the right heat pump for the climatic conditions of the region where you live. Some of the Hitachi air-to-water heat pumps are capable of maintaining their performance down to -25 °C outside. In these extreme situations, an electrical backup resistance comes into operation to maintain comfort.
  • 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.


Air-to-water Heat Pumps Hitachi Yutaki



Hitachi Heat Pumps for Efficient Cooling and Heating


As you have seen, what defines air source heat pumps is the versatility to cool your home in warmer months, and provide heating from renewable energy through the same system during colder months.


Within the Hitachi Air Conditioning product ranges, you will find a wide range of air-to-air heat pumps, among which you can find different models such as wall units, consoles or ceiling units.

Also, the Yutaki air-to-water heat pump system, which offers heating, cooling and/or domestic hot water all in one. The name Yutaki isn’t mentioned without being followed by the word efficient, as the range has been praised for having the best COP and best EER on the market.


You can find more detailed information about the Yutaki range in our article – Heat Pumps Explained: The Electrification of Heating, here.


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, check this link to see our ranges.


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