Andrew wrote:

On Fri, 28 Nov 2003 08:25:42 +0000, The Natural Philosopher
wrote:


I am finding blackthon quite poor unless got up to really high temperatures.


It's a minor species so I do not have a lot of experience with it. It
is often of small dimension and thus not split. Round logs take a bit
more for the fire to take a hold (vertices heat up quickly to catch
fire).


I suspect in a centrally heated house the chimney effect of the open
fire evacuates more heat from the house than it contributes.


No, I don't find that. Particularly in my house where underfloor vents
feed the fire directly with icy cold air for burning.

I would say that having the open fire both slightly ventilates the room
and draws out hot steamy air, and adds between 3 and 5Kw to the heating
of the room at full crack.


If you're happy with this I'm not tempted to dissuade you. It would
make an interesting maths problem involving the temperature difference
between room, flue gases and outside, mass flow of combustion
products, draught of chimbly and radiant energy through about pi
steradian?? from the hearth...



Actually its a lot easier. Run the CH at a given setting, and light the
fire. Room gets warmer. QED.

Prat.


Still, I'm no numbersmith

AJH