Jo wrote:

this doesn't seem like a radical request but I want to use the big
fireplaces that I have in my house for the primary heat source so that
I can discard the central heating system and especially the radiators
that stop me putting furniture against the walls they blot. Coal is
out - I want something that maintains the apartment heating with a
thermostat - and I want it to be warm in the morning, So no coal, no
coal!

I have explored flame effect gas fires but apparently no useful heat
output is generated. And flueless devices, it seems cause excessive
condensation.

How can I usefully use the vacant space in my big fireplaces to
generate heat from a gas supply. I want the answer to be aesthetically
pleasingly as well as efficient as possible.

My only other option is to install a combi heater and keep the
radiators.


If these fire places are big 'inglenook' types they are never going to
be efficien.
The most efficient form of (non boiler) gas space heating is the bog
standard outset radient/convector gas fire (about 75% efficient), but
very ugly.
The inset live fuel effect types are in the 40-60% range.
Neither type is suitable for automatic operation to the best of my
knowledge.
In all cases you would have to reduce the opening to fit the 'normal'
sized appliances.

The display type (grate burners etc. ) are very very inefficient (even
negative - ie. they make the place colder when used). And would likely
need to have a partial restiction in the size of the opening.

There are lots of ways of using a boiler to heat a house without useing
bog standard rads - at a cost.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html