As far as I can tell your boiler has a low efficiency rating 65-68% and modern boilers are 90% efficient or more. All new Boilers are by law of the Condensing type which means that waste heat is used to heat incoming water.
I believe the regulations now require the incoming gas pipe to the boiler to be 22mm rather than 15mm - this may mean extra expense for you with the cost of running in a bigger supply pipe.
Reading through trade discussions I notice that the "experts" generally have only good things to say about Worcester Bosch boilers.
A combi (combination) boiler has advantages for small properties particularly in a new-build property. With a combi you have no stored hot water - no airing cupboard - no emergency backup from an immersion heater - and filling a bath can take a long time and more so in the winter.
Combis are a little more complex and therefore prone to fail more often. A combi delivers hot water at mains pressure so no pump is required for a shower.
I am no expert but would expect the cost of a new boiler and installation to be in the order of £3000 or more - unless you engage British Gas in which case it will likely be much more.
I have no specialist knowledge, skills or experience. My advice is worthless.
The summer is a good time to have a new boiler installed - Gas Engineers are often very busy in the winter months.
I also notice on here from time to time that some spare parts for some Neataheat boilers are difficult / impossible to find.
Good luck...
Peccavi
May 2010
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