Barn or old cottage conversion - Insulation/Heating

JDB1 wrote: »

Have found a barn I would love to convert (and an old cottage as plan b). Have been told that if I put in cavity walls to insulate then the stone behind will start weeping at some point in the future as it won't be able to breathe (sea sand used in construction?) but if I leave it open to breathe then the place will be freezing! Would like to leave some stone exposed to keep the character but would also like a toasty home. Can anyone advise how best to insulate? Also best method for heating? Thanks

Hemplime or a host of natural hydroscpic materials available on the market, maybe ewi of cork or mineral wool with lime render. Breathable wall doesn't mean ventilation or have anything to do with thermal performance.
Deal with insulation, air-tighness and ventilation, 'breathabile wall' and weather tight detailing and solar gain layout then heating. Have you wood available? Can afford ground source heat pump, or solar thermal store, how many is the house catering for? do you care about co2 emissions or just The cheapest option? It may be gas..