KAESER Know How blog post: Reduce your energy costs with compressed air heat recovery
KAESER Know How Blog

In this blog post we discuss what compressed air heat recovery is, the applications and how it can save you money.

A lot of hot air?
KAESER Know How Blog

In this blog post we discuss what compressed air heat recovery is, the applications and how it can save you money.

A lot of hot air?

A lot of hot air?

How to reduce your energy costs with compressed air heat recovery

We’ve all seen fuel prices surge at the pump in recent weeks and no doubt we’ll see the knock-on effect over the coming months with other associated prices going up too - not least electricity. So how can you minimise the impact? With winter around the corner and cooler weather ahead - one option may be to consider implementing a compressed air heat recovery system. In this blog post we discuss what compressed air heat recovery is, the applications and how it can save you money.

What is compressed air heat recovery?

Whether you operate rotary screw compressors, boosters or blowers - all of these technologies convert almost 100% of the electrical drive energy supplied to them into heat. Whilst 2% of the energy input remains in the compressed air and another 2% is dissipated into the ambient surroundings, approximately 96% of the energy input can be theoretically recovered for reuse!

Heat flow diagram
Heat flow diagram

But, where does the usable energy in compressed air come from?

The answer is actually quite simple and perhaps surprising. During the compression process, the compressor converts electrical drive energy into heat energy. At the same time, it charges the intake air with energy potential. This corresponds to approximately 25% of the compressor’s electrical power consumption. However, this energy only becomes usable when the compressed air expands again at its point of consumption and, in doing so, absorbs heat energy from the ambient surroundings. Of course, the amount of energy available for reuse depends on the pressure and leakage losses within the compressed air system.

What can the heat recovered from a compressor, booster or blower be used for?

Recovered heat can be used for a number of purposes; 

  • Hot air can be used for the purposes of heating space. Possible applications include drying processes, heating of buildings and warehouses, air curtain systems and the preheating of burner air. It can also be used to supply heat to a central heating system, laundry facilities, electroplating and general process air.
  • Hot water. You might be thinking that heating is not necessary at all or just for very short periods of time during Winter. However, heat recovery can also be used to a greater or lesser extent throughout the year for heating water. This can be used to provide heating and service water on demand at temperatures up to +70oC or even 85oC if required.

How do you implement compressed air heat recovery?

Hot air

As self-contained complete systems, modern rotary screw compressors, boosters and blowers are especially well suited for heat recovery systems. Neighbouring spaces can be heated simply and effectively via exhaust air ducting. When the recovered compressor exhaust heat is being used for space heating purposes, exhaust air ducting simply feeds the heated cooling air to wherever it is needed, thereby allowing such spaces as storage areas or workshops to be heated free of charge. A ventilation flap allows the heated cooling air to be conveyed outside during summer operation or to the areas that require heating during winter operation.

Heating with hot air
Heating with hot air

Hot water

PTG plate-type heat exchangers are used for standard applications using heat recovery systems for the production of hot water and service water. Special, fail-safe heat exchangers are used in the case of operations without an interconnected water circuit, or for applications with the highest demands of purity for the heated water, such as with cleaning water in the food industry. Up to 76% of the electrical power originally supplied to a compressor can be recovered for use in hot water heating systems and service water installations.

Heat recovery process for hot water
Heat recovery process for potable water applications (only possible in conjunction with special, safety heat exchanger).

What is the savings potential of compressed air heat recovery?

Here’s an example of the savings potential per year of implementing heat recovery.

Plate-type heat exchanger systems Compressor size
"Small" "Medium" "Large"
Compressor model SM 16 BSD 83 FSD 475
Drive motor rated power 9 kW 45 kW 250 kW
Potential savings per year: Heating oil $857 $9,037 $45,522
4,671 kg CO2 49,285 kg CO2 248,274 kg CO2

If you operate rotary screw compressors and you want to see what their usable heating energy volume is - then just click here to use our heat recovery calculator.


Heat recovery is a smart way to reduce your energy costs by putting to work heat that is being made by compressors, boosters or blowers that would otherwise simply disappear into thin air. Not only can it reduce your primary energy consumption, but it can also significantly improve your overall energy balance. And, by reducing your energy costs you are not only saving money but also reducing your carbon footprint - good for the bottom line and good for the environment.

Enquire today!

Reduce your energy costs with a heat recovery system

Find out more about compressed air heat recovery with Kaeser Compressors and discover your energy savings potential! Just phone 0800 447 820 or fill in the form below and we will get back to you.

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