"Neil Jones" wrote in message
...

"IMM" wrote in message
...

"Neil Jones" wrote in message
...

I read this document as a simplistic attempt to estimate the payback
of
the installation. Long flues can be used but they will incur extra
expense and so impact the payback period.

Not necessessily. I recommended to install a Keston boiler in a loft
in a
knocked up ply or MDF cupboard at a end gable, with some insulation
over,
and run the flue the length of the loft to the other gable using cheap
plastic waste pipe. The heat of the flue pipe will assist in keeping
the
loft slightly warmer. Feedback was that the loft is far warmer in the
recent cold snap. Plastic pipe is cheap enough to buy and a benefit
too.

Of course, but if you start saying "extended flue +200 points unless you
can use twin plastic pipes in which case +50" it starts getting more and
more complicated

This form assumes the person filling it in knows the market and what is
available. That is a poor assumption when taking into account and industry
that has only just accepted non-cast iron boilers.