30 May 2005
In January of 2001, for the first time in the world, The Tokyo Electric Power Co., DENSO CORP.,
and Central Research Institute of Electric Power Industry have reported the practical use of the CO2
refrigerant heat pump water heater for residential use, which can save more than 30% of energy
compared to conventional combustion type water heater.
The nation has started a subsidy system in September of 2002, and at the end of March, 2003,
about 120,000 of the system have accumulatively forwarded to the whole market and now it continues
to spread around well. As the market spreads, many types of system according to their uses and
functions; such as system for apartments, for cold places, system with floor heating, have been
In this report, the present status of the spread in Japan, the improvement of performance compared
to the first model which was reported in the last conference (The 7th IEA Heat Pump Conference 2002,
Beijing), the variations, and the future view of the CO2 refrigerant heat pump water heater for
residential use are discussed.