On Mon, 16 Jan 2006 14:54:15 +0000, Andy Wade wrote:

The Natural Philosopher wrote:

But what energy costs? Agas are MORE efficient than CH boilers.

That's complete nonsense, surely? How can an open-flued non-condensing
appliance possibly compete with a modern condensing gas boiler?


Quite easily. It uses a long flue path to extract the heat down to an
effkux temperature up the flue of about 35C.

With CH water running at higher than that, even in a codensinng boiler,
more heat has to go out of the boiler flue than the aga flue.

The ONLY thing that marks boiler efficiency is how hot the exhaust gases
are when they leave the house and go through the insulation.

That and the initial combustion temperatures, which are fairly similar in
both cases.