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COP claims for heat pumps are controversial and consequently need good references. I don't see a reference for the claim "The EcoCute derives two units of energy from ambient air temperature for every unit of electrical power it requires. Each of these one unit plus two cost free units ..."
The comparison of the COP against a gas boiler is also misleading for two reasons. Firstly, modern gas boilers don't have a pilot light loss for the simple reason that they no longer have a pilot light! Secondly, and more important, when comparing electrically powered devices against direct use of primary fuels it is necessary to consider the carbon emissions of the electricity generating stations. This varies hugely from country to country. 188.8.131.52 (talk) 15:44, 7 January 2009 (UTC)
"The EcoCute's COP is 3.8 in industrial use, while electric power water heating is 1.0, and gas boiler is 0.88 including pilot light loss." Comparing COP and efficiencies (in this case for water heater and boiler) is misleading at best, false in most cases. For such comparisons (especially next to carbon footprint claims), it is probably better to compare primary energy usage. Laurentsavaete (talk) 18:38, 17 January 2009 (UTC)
COP of gas boilers varies widely from around 65% to almost 100%, depending on design. Its simply incorrect to attribute it any one fixed figure.
Also a heat pumps claimed figure doesn' equal real life performance, since the real world COP varies very widely depending on input and output temps. So to compare a manufacturer's spec, which will always be for optimistic conditions, as if it were a fixed figure, with other heating options is really very misleading. 184.108.40.206 (talk) 22:03, 3 July 2009 (UTC)