Heating in a well insulated house

Robwiz

A pellet boiler can be a good solution – it depends on the competence of the system designer and installer. The capital cost can be high – depending on the degree of sophistication/automation – with bulk storage hoppers and feeders. Otherwise, it's a similar way of life to using oil (except that keeping the pellets dry is vitally important). And you'll need a large boiler room and pellet storage area.

I suspect your heat demand will be quite low, so choosing a boiler that's the right size and that modulates will be critical.

When I researched biomass (and if you search this forum for 'pellet stove' there are some long discussions) it appeared that there is more to go wrong on pellet boilers than log boilers and that owners of the latter tended to be more satisfied with their installation. The combo of pellet boiler with underfloor emitters is probably the most complex heating system design imaginable!

Selecting the right contractor appears to be critical. As biomass is part of the renewable heat incentive bonanza, there are many installers who may not be around to provide long term support and service. There are accounts online written by people who took great care in selecting the right manufacturer and pellet boiler but have been let down on maintenance which has turned out to be very costly and traumatic.

Have you decided what your priorities are? Which of these are most important for you: low energy bills, low initial capital cost, easy maintenance, reliability, minimal space utilisation, instantaneous response to temperature changes?

Johnandabby

BT problems so I lost internet for a week - first world problems eh!

You would need a good size thermal store as the pellet boiler wouldn't be operating for any real length of time with a very well insulated house. Good luck getting that sized correctly!

Storage is difficult to prevent the pellets getting moist.

Capital costs are ridiculous for self feeding MCS accredited pellet boilers, even with the renewable heat incentive paybacks taken into account - RHI payments are for 7 years, so you need to look at what year 8 is going to cost.

And the RHI paybacks will be based on you continuing to use pellets, which are much more expensive to purchase than logs. The govt is also looking to introduce responsible sourcing targets for pellets in autumn, which is likely to increase supply costs.

Biomass would be far down on my list of options...