On 29 Sep, 17:17, "R D S" wrote:
We have a living flame gas fire in our front room. I only ever use it in
desparation and then only on low.

I am about to put a radiator in that room which will complete the central
heating I started nearly 15 years ago! I wonder how much of the heat from
the rad is simply going to dissapear up the chimney, I am guessing it will
be quite a bit.

Anyone any real life experience of this? I have looked at numbers on the net
but these are from people selling solutions.

Ta.

we fitted stoves in place of our open fires- so not direct experience
per se BUT I do remember an inflatable chimney bung that would do what
you want - can;t remember the tradename tho - sorry!

From memory you inflated it with a bike pump and it was supposed to
seal it all up nicely - when you want to use the fire let it down and
out it came. Had a red ribbon to remind you it as there...

it may help
cheers
JimK