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 Volume 3, Number 3, Sept. 2005 (352 KB) features:

• First news of a new dehumidifier/heat pump water heater, from Oak Ridge National Lab, Western Carolina University , and A-B Tech.  All HPWHs dehumidify while they heat water; this one continues dehumidifying as needed, when the water is already hot.
• United Technologies Research Center has begun field testing their commercial-sized heat pump water heater.  It uses CO₂ as a refrigerant.
• Heat pump water heaters are becoming more popular in Australia , as state governments offer rebates and electric water heaters have been largely banned.  Further helping, HPWHs are considered a type of solar water heating.
• First news about a Federal tax incentive for heat pump water heaters.
• We update you on the Japanese “EcoCute” residential HPWH that has become immensely popular in Japan .
• We surveyed In Hot Water readers, to see how many of them actually use a HPWH in their own homes.

Volume 3, Number 2, December 2004 (474 KB) features:

•  An update on United Technologies Research Center ’s CO2-based commercial HPWH.

• A story about a water-source HPWH that was installed, as a retrofit, in a high school in Tennessee .

•  A study by Oak Ridge National Laboratory that compares the efficiencies of several residential hot water distribution systems.  It compares plastic and copper tubing, attic vs. under-slab piping, and “parallel” vs. “trunk and branch” systems.

• An update on the Japanese EcoCute CO2 HPWH.

• Several companies are building heat pump water heaters in China.  Some models are being licensed from     Quantum in Australia, some manufacturers have been developing products locally.  We report on five manufacturers, and show pictures of their products.
• We previously reported on Quantum Energy Technologies Ltd. in Australia.  There is also another similarly named company, Quantum Energy Systems International, who licenses HPWH technology in several Asian countries.
• Peter Thompson, from Auckland, New Zealand supplied us with some history of the development of the Mahana Blue dairy water heating system, for which he holds patents

Volume 2, Number 6 - July 2004, (441 KB) features:

• Quantum Energy Technologies Ltd. heat pump water heaters (HPWHs) are made and sold in Australia.  They are Australia's largest manufacturer.
• Cap-Aus Ltd. and Dux Hot Water Ltd. are Australian manufacturers and marketers of add-on heat pump water heaters.
• Rheem Australia is the newest addition to the Australian market.
• Ochsner GmbH in Austria makes several HPWH models for the European market.
• The Mahana Blue from New Zealand is a unique application for a heat pump water heater.  It is used on dairy farms to heat water for  washing and sterilizing in the milking shed.
• Some thoughts on the differences between U.S. and non-U.S. HPWHs.
• Electric (backup) heating elements: when to use them (or not).

•  Summaries of recent HPWH meetings
•  The California Energy Commission's final report on its field test of 20 EMI Watter$aver HPWHs
•  Oak Ridge National Laboratory's final report on its durability test of EMI Watter$aver and Nyletherm-110          HPWHs
•  A brief update on the AERS E-Tech R-106-K5 residential HPWH.

Volume 2, Number 4  (237KB) features:

• Some new HPWHs use CO₂ as the refrigerant, rather than a Freon-type gas.  United Technologies Research Center is developing a commercial CO₂ refrigerant HPWH system.   

• Several Japanese companies are selling residential CO₂-based HPWH systems. 

• Also, some HPWHs are keeping dolphins warm at Gulf World Marine Park.

  Volume 2, Number 3 (265KB) features:

• HPWHs are used for swimming pool heating, not just for domestic water heating. 

• We show a table comparing pool heating costs with various fuels, and list the various brands and models available. 

• There is an update on a field test of HPWHs by Connecticut Light & Power Company. 

• Oak Ridge National Lab demonstrates the electric demand savings that a residential HPWH achieves.

  Volume 2, Number 2 (1,642KB) features:

• Our lead article has basic technical information on HPWHs.  

• There is an article on NYSERDA’s HPWH program. 

• We tell about a HPWH cost-effectiveness calculator from Aspen Systems. 

• There are two articles about the Enviromaster International (EMI) Watter$aver brand residential HPWH, including an update on a field test conducted by the California Energy Commission.   

• There is an article about an Australian HPWH that includes solar collectors.

  Volume 2, Number 1 (243KB) features:

• Our first article talks about what a HPWH is. 

• There are notes about two commercial-sized HPWHs. 

• We report on a first test, by Oak Ridge National Lab, of the EMI Water$aver HPWH. 

• We tell about WATSMPL, a modeling software, that allows you to calculate the energy cost of any type of residential water heater. 

• We discuss a suggested test procedure for commercial HPWHs.

• There is a Tech Talk article about how an add-on HPWH should be connected to a storage tank.

• An article by Titu Doctor and your editor discusses some hard-won experiences with HPWHs.

  Volume 1, Number 1 (198KB) features:

• We begin with a feature that discusses a homeowner’s experience with a HPWH. 

• The EMI Watter$aver HPWH is introduced.

• We explain the difference between an “add-on” and a “drop-in” or “Integral” HPWH.

• We list the manufacturers of residential HPWHs.

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