Restored a grade 2 listed stone ruin including a (prototype) biomass boiler and spent many hours taking it apart and putting it back together! Also explored the (then available) means of insulating stone houses. Now moved to another stone house that needs improving. Considering both biomass and ground source heat pump and exploring insulation. I am single, retired and short so manageability is important to me!
Unless you have a huge hopper, a biomass boiler can be a complete pain as they need filling so frequently. If you go away then you have a cold house. They can also need dashing and cleaning frequently.
Questions to ask:
How often does it need filling?
How often does it need de-ashing or cleaning?
Can you actually loft the bags of pellets into the hopper? Will you still be able to in 10/15 years?