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Adrian

HI

wrote:
The Wiki strikes again... another one for review

This article compares the various types of electric space heating.

big snip

==Heat pump==
There's only one type of electric heating that can beat 100%
efficiency, and that's a heat pump. These can give equivalent to 300%
efficiency by using the leccy to pump heat in from outdoors. Since all
heat pumps take heat from outdoors, they must be installed one way or
another.

===Air source heat pump===
Air source heat pumps are the cheapest heat pump. These use a coil and
fan to extract heat from the outdoor air.

The downside of air source heat pumps is that efficiency and hence
energy delivery falls as outdoor temp falls. When the outdoor coil
freezes, which happens somewhere in the region of 5C and below,
efficiency drops much further, making them ineffective heaters at such
times.

Sometimes the units are reversable, also able to operate as air
conditioning in summer.

===Ground source heat pump===
The downsides of ground source heat pumps are that a huge and costly
layer of ground tubing needs to be laid. This takes a large area of
ground.

IT's not so much the tube that's costly - but burying it in the
ground... - especially if you already have a nicely-landscaped garden!

Over here (South-West Ireland), lots of new-build houses require
significant amounts of earth to be moved around at the initial stages to
create a level plot - and if the collector tubes can be installed while
the other ground works are being carried out then it's only an extra
day's 'digger time'.

You can also collect heat from a decent-sized pool or river - in which
case the installation costs are minimal...

Adrian