Upgrading heating system / energy - best option

Reed_Richards

I can't see that the boiler itself will lose a lot of heat but the pipes to and from might.  Well maybe not a lot either but heat lost in the loft is wasted heat whereas heat lost from exposed pipes in rooms or pipes embedded in the interior walls will find its way into the rooms and so is not wasted.

(Okay @matelodave, you've convinced me).

Screwdriva

Been down this road myself and found the following:

1) A Vaillant gas boiler is the most efficient and reliable heating solution today
2) Radiator Reflectors really do work
3) As do tripple glazed windows
4) Solar panels work throughout the year but will only cover all of your usage for 9 months. Batteries don't make financial sense. Avoid only if your roof faces North.
5) Insulating wrap on your hot water pipes is a great idea. As is underfloor heating!