Extension heating options

[jack]

A single storey building in a L shape, I have planning permission to develop one leg of the L into accommodation. The other leg is accommodation (converted in 2005) as is a small part of the leg to develop, if that makes sense.
There are two outbuildings to be converted and extended, by removing the existing wall and building a new wall 2m further out.
Currently 59m square, to increase to 99m square.
Heating is currently a Worcester Heatslave 12/14 combi, which is more than adequate for the rads. Usually no more than 30% of max. Oil used per annum is 750 Litres, so not a lot.
This boiler is 82% efficient the latest regs require one which is 85% or better.

UFH has been suggested for the conversion. I have been reading up on renewables and looking at air source and or solar water. The area for the UFH is 50m sq, as the bedroom will be redeveloped.
The existing accommodation has six rads including the one in the bedroom.

How do I decide the heating system to use?
E.G. do I use a water cylinder and cold water tank in the loft and a new boiler? Or is a heat store a better system? Or would a larger combi be a better method?

How are UFH systems designed? Presumably by knowing the insulation values of the walls and floor to determine pipe spacing?

 

[Howsie]

I'd advise you to get someone in to measure up and do the calculations for you. There are many things to consider and making a decision from a few posts on this forum probably won't be the right one.

 

[chris watkins]

I'd advise you to get someone in to measure up and do the calculations for you. There are many things to consider and making a decision from a few posts on this forum probably won't be the right one.

Jack you might even want to consider paying them for this !!! shock horror :death:

but you will pay one way or the other for these skills, it is often best to pay upfront & then use this info to obtain comparable quotations.