On Wed, 5 May 2004 19:48:58 +0100, "G&M" wrote:


"Pete C" wrote in message
.. .
Air to air are inefficient near to 0C, they cannot provide enough heat
for
DHW, only acrting as a pre-heat.

The high efficiency ones would be about 15% less efficient at 0°C.
With a COP of 6 to 6.5 that's still pretty good

Still struggling to see how these reach that COP figure as the laws of
thermodynamics tend to get in the way. Talked to a friend who's more into
physics and he's asking Hitachi for more information.

Though his first reply was along the lines of audio amplifiers in that it
was "COP music power"
Hi,

AFAIK the theoretical limit is still some way off, give it 5 years or
so and a COP of 8 might be possible.

Still it's a better than only getting quoted only BTUs, or possibly
even watts as well if your lucky.

cheers,
Pete.