CO2 Heat Pump

Energy-efficient, renewable residental CO2 heat pump

DENSO’s CO2 Air to Water Heat Pump was first introduced into Europe in 2009 and set a new standard for compact size, light weight and low noise.

Features and Benefits

  • An air to water heat pump is a very efficient device used for house heating and hot water production.
  • Its heat energy output is about three to five times as high as the electricity input.
  • The technology is similar to that of an air conditioning system: it uses a refrigerant cycle with a compressor and heat exchangers to extract heat from the ambient air and transfers this heat to water.


A CO2 Air to water heat pump is a good fit for:

  • High temperature heating demand for domestic hot water
  • Space heating for well-insulated homes (nearly-zero energy homes or passive houses)

Winner of environmental awards

DENSO first introduced CO2 refrigerant to its Air to Water Heat Pumps in 2001, in Japan. Known as ‘Eco-Cute’, the product‘s improved energy efficiency meant that less domestic electricity was required. 

As a result the innovation won six globally recognised energy and environment awards, including the 2002 EPA Environmental Climate Protection Award from the U.S. Environmental Protection Agency.

It is supplied as original equipment to heat pump manufacturers. DENSO CO2Heat Pumps are now starting to be used in homes across Europe, supplying efficient, eco-friendly under-floor heating and hot water.

DENSO World First Technology

When designing the Air to Water Heat Pump, DENSO’s engineers wanted to achieve heating comfort and efficiency in a more environmentally responsible way – echoing DENSO’s Vision 2015 of a greener and safer future society.

The first breakthrough was to change the refrigerant. Typically heat pumps use a synthetic refrigerant gas such as R410A, which has a Global Warming Potential (GWP) of 1725. 

To improve on this, DENSO’s Air to Water Heat Pump was the world’s first heat pump to feature the natural refrigerant carbon dioxide (CO2) – which has a GWP of just 1.