"Andy Hall" wrote in message
...
On Mon, 16 Jan 2006 15:51:15 +0000, Peter Parry
wrote:

On Mon, 16 Jan 2006 13:46:07 +0000, The Natural Philosopher
wrote:


In terms of being a conveniently located heater, of attractive design (in
a
traditional setting), that is actually MORE efficient than an oil or gas
boiler,

They are not more efficient than a modern oil or gas boiler - the
range cooker industry even had to negotiate a category of their own
for water heating because they found it difficult to reach even 85%
efficiency, most still wallow around 75%.

We weren't discussing water heating. Other than as a backup in case
of electricity failure, it isn't interesting to heat water cylinders
at a rate of 3-5kW.

In terms of space heating, if one compares flue temperatures at exit
from the house it is clear that a gas Aga with conventional flue is
very efficient.


Come on Andy, The flue of an Aga has a draught break which entrains lots of
cool air so any temperature after such flu break is NOT an indicator of
efficiency
I used to laugh when I came across test point holes drilled after flue
breaks, usually with service record cards dutifully filled in with
combustion analyser results taken straight out of the manual but quite
obviously not the readings from the point :-(