Dave Liquorice wrote:

"Since changing to Cleanburn I find the house much warmer and have had
to turn the temperature down making it more economical - even the
boiler needs less servicing".

Classic!

I reckon it's probably low sulphur, which means low sulphur
dioxide in the exhaust, and less corrosion of the baffle
plates/heat exchanger. But enough to make a difference? I don't
know.

--
Grunff