Re: Would this be enough?
Muffin
You only need additional bulk storage space if you have a pellet boiler which provides your central heating, hot water etc. If you just have a pellet stove which just heats the room it's in, it will have a built in hopper into which you can empty pellets by the bag. There is an increasing number of fuel merchants selling them by the bag now. We installed ours last November and have never had a problem getting pellets. This is not the cheapest way to buy pellets but that's not why we bought one.
Details for the models that qulaify for the SEI grant can be found at
If you download the product list, there will be a web address for most of the manufacturers and installers, so you can do quite a bit of research. There is in general some very useful information on pellets and sustainable technologies throughout the SEI site.
You could install a wood burning stove, most models will provide brilliant heat for your extension (Most pellet stoves can only burn pellets). However the flue installation can be quite tricky for a single storey extension to a double storey house, as it must be brought up above the eaves of the existing house. This may also be expensive. The main reason we went for a pellet stove was because of the very simple flue installation. Another disadvantage is that a traditional solid fuel stove will heat up really hot so if there are kids around, it will have to be guarded off.
I have no vested interest in pellet stoves, but ours is fab, I can't understand why more people don't have them.
Hope this helps
J2K