I have a large 4 bedroom dormer bungalow built in 1989. I was wondering how I go about improving the energy rating to A standard.The cavity walls have 2 inch insulation, Attic is insulated.I have double glazed teak windows with oil fired heating and open fireplace with back boiler.As the front of the house is sandstone external insulation on the front is not an option,Though the back and sides of the house could be insulated externally. I also have the option of dry lining internally also.Was considering installing heat pump and maybe solar panels.Just wondering is it possible to bring this house to A level given that there is no floor insulation.If anybody has done a similiar job any advice with regards to the above.Can one combine external insulation with dry lining. ?Trying to figure estimated cost with use of possible grants.