Using air conditioning systems for heating as well as cooling

Most modern air conditioners not only cool but also have a heating function. This makes sense, especially in cold seasons. You will learn how heating works with air conditioners, the advantages and disadvantages of it and how you can even save money with air conditioner heating.


  • With efficient air conditioning, you can quickly heat up your rooms
  • Save money on heating when relying on highly efficient air conditioners
  • Split air conditioners are the first choice for heating-climate units

Your mobile air conditioning does not have to be in the storage room in winter. Your split air conditioning system also has a benefit in winter. We will tell you how to optimally heat with your air conditioning in the cold seasons. This is how you use your air conditioning all season.


How air conditioning heating works

How air conditioning heating works

Heating with air conditioning works in the same way as cooling. The only thing is that no warm air is carried out of the room, but the circuit works exactly the other way around.

The outer unit of a split air conditioning system recovers heat from the surrounding air and releases it inside. The compressor technology then works like this:

  • the refrigerant evaporates in the outdoor unit and absorbs heat
  • In the indoor unit, the refrigerant is liquefied. It releases the heat.

In this process, it is called an air/air heat pump. The heat of the outside air is transferred to the indoor air.

Reading tip: How does air conditioning cooling work?


Advantages and disadvantages when heating with air conditioning

There are advantages and disadvantages when heating with air conditioning.


  • compared to gas or electric heating, more energy-efficient
  • The temperature rises faster as opposed to water heating (generates heat immediately)
  • The air conditioner is used and is not standing around
  • Heating for a low purchase price
  • Air is cleaned at the same time
  • other heating costs (such as oil or gas) are eliminated


  • higher noise development in the living area than water heating
  • Efficiency decreases the more you heat
  • the more you heat, the more electricity you use
  • there is draught

Especially in rooms that are only used in a certain season, the use makes sense, and you do not need an extra heater in winter.

These are, for example:

  • Apartments
  • Garden foliage
  • Caravans and motorhomes (reading tip: Mobile air conditioning in caravans)
  • Cellar rooms without connected heating
  • Boats and houseboats

Another disadvantage of heating is the installed split devices, which are located on the wall under the ceiling. In summer, this is a strong advantage, as the cool air drops downwards (it is heavier than warm air).

In winter, however, this is a disadvantage. The warm air does not sink down where you need it. There is a temperature gradient between the upper and lower air layers. However, this disadvantage can be counteracted by optimally placing the cooling units. There is also the possibility to install ground-level flat consoles.

Flat console air conditioners distribute the heat during heating even near the ground


Regular cleaning in continuous use

If you use your air conditioning all year round, don’t forget regular maintenance and cleaning. Due to continuous use, the filter must be cleaned more often. The air conditioning expert recommends cleaning twice a year.

Reading tip: Who installs and maintains mobile air conditioners and split devices?


A word about humidity in winter

In summer, a lower humidity is optimal. Because high humidity creates sultry air, and you sweat more.

In the cold seasons, however, low humidity is not optimal, so it is best to adjust your air conditioning in such a way that the humidity is not lowered. Too dry air by air conditioners allows your mucous membranes to dry out, increasing the risk of infection due to germs. The result: you get sick.

Reading tip: Do air conditioners make you sick? – myth or reality?


Purchasing guide for air conditioning systems with heating

You want to use your air conditioning all year round and also heat it with it? Then you should especially check these properties on the air conditioner:

What type of device do you want?

There are three common types of air conditioners that can heat.

  • Split air conditioning
  • mobile air conditioning (monoblock)
  • Air cooler (with heating function)

All three species have their advantages and disadvantages.

Split air conditioning

  • consists of two modules (interior and outer part)
  • must be permanently installed by a specialist (approx. 250 – 600 €)
  • Acquisition costs high
  • lower electricity costs, as very efficient cooling and heating

mobile air conditioning

  • no installation, ready for immediate use
  • Acquisition costs medium
  • medium electricity costs, as very efficient cooling and heating

Air cooler

  • no installation, ready for immediate use
  • Acquisition costs low
  • low electricity costs, but also only low heating options
  • only to be used as an additional device

If you have found the right device, ask yourself the following questions:

  • What is the power in Watts? How much can the device heat?
  • How much electricity does the air conditioning system consume?
  • Is the noise level appropriate for them?
  • How intensive is regular maintenance?

Use our calculator to calculate the cooling/heating requirements in advance!

Calculate your cooling requirements in watts and BTU

How much watts and BTU do you need for your apartment, your rooms or your house? Our cooling requirements calculator helps, which makes a recommendation for the watt number to be searched as well as the BTU.

Calculating cooling requirements


They will save money, but their power consumption will increase.

If you use your air conditioning for heating, you will save costs. Keep in mind, however, that you will only save if high-efficiency air conditioning systems are used. An air cooler is not a highly efficient device. For very efficient heating, you need to use split air conditioning systems. Unfortunately, mobile air conditioners are not as efficient as split devices.

Calculation example: You spend 2000 euros on heating oil. Now you have a mobile air conditioning system with 2900 watts of heating power. These operate from November to March (roughly 150 days) every day for 8 hours.

The following costs are incurred: • Electricity consumption per year: 3480.00 kWh– electricity costs per year: 1044.00 Euro Savings: approx. 956 Euro per year.

That sounds good at first, doesn’t it? Keep in mind, however, that you will certainly need to heat not only a one-room apartment but several rooms. Therefore, you need multiple devices.

Calculate your electricity consumption in euros and kWh

How much electricity will your desired model consume on the day and year? Just make it happen now, and they won’t have any surprises.

Calculating electricity costs


Recommendation for air conditioning with heating

Below we have selected common and popular devices from the three categories:

  • Split air conditioner
  • mobile air conditioning and
  • Air cooler

Questions and answers

 Can any air conditioner heat?

No, not every air conditioner has a heating function. Look into the product data-sheet if you have chosen an air conditioner to see if this device can also heat.

What temperature must be set at least during heating?

Most manufacturers equip their air conditioners in such a way that they have to heat at least 16 degrees.

 When does the air conditioning turn off and can no longer heat?

Many devices have no problems with outside temperatures around 0 degrees. However, some manufacturers recommend at least 0 to 5 degrees. Underneath, the system switches off. However, there are also split air conditioners that are functional up to -10 or -15 degrees. If the temperature falls below, the outdoor unit thaws by itself.

 Which energy class should be chosen for heating, at least for an air conditioner?

The lower the energy class, the more electricity you use for operation. Especially when it is really cold, the system needs a lot of electricity. Therefore, it is better not to buy an air conditioner that does not have at least the energy efficiency class A.



Even if many owners of air conditioners do not know: heating with air conditioners is possible. And you’ll even save costs if you opt for highly efficient air conditioning.

Air conditioners that combine cooling and heating are particularly useful. This allows you to control your room temperature with just one device all year round. And not only that: you can still enjoy air purification and dehumidification.

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