Many thanks for your responses. I admit I didn't provide enough information about the whole picture I was just trying to get an idea, but I see that doesn't really help, so here goes on what we are trying to achieve.
We are a small Dog Hotel business and we occupy a large building, all the rooms for the dogs have electric underfloor heating, but the rest of the building has nothing. As we live on a farm we have an abundance of wood and installing a Wood Boilers seems the right way to go.
Our immediate aim is to provide heating for the reception area ~45m2 and the main hallway ~63m2. Our secondary aim is to increase the temperatures in the dog rooms themselves in the event we have an very cold winter, currently they are at acceptable levels, but we want the option just in-case it does get extra cold.
Our long term goal (i.e. a few years) is to connect this system to the main house (about 20m away), so the idea of the accumulator has already be assumed.
Back to the Dog Hotel, pretty much the entire place is either stone or concrete.
We are still in the planning stages (planning to install it before this winter), so we can easily change things. I.e. the UFH, this was just an stab in the dark as a possible solution for heating the reception.
The boiler is planned to be housed in the store room that is adjacent to the reception and we were thinking additionally of using an extraction fan to draw warm air from the store room into the reception.
Providing heat to the dog rooms is the tricky one as we can't install anything at ground level to a level to which any dog can reach. At the moment I'm thinking of running a large pipe above the door frame, and hoping the hot water heat would cumulatively help increase the room temperature by a couple of degrees. ??? Maybe
We are looking at installing this in parts and over time to help save money, i.e. just get reception warm, then later move on to the other areas.
Hope this helps, and any help provide is very much appreciated.
Thanks