to have neighbours to come on board with you to have that neighbours to come on board with you to have that kind of shared ground loop system. if that s not feasible and it loop system. if that s not feasible and it is quite difficult if you are privately and it is quite difficult if you are privately owning a flat your option then privately owning a flat your option than is privately owning a flat your option than is to privately owning a flat your option then is to have an air source heat uumo then is to have an air source heat pump. that then is to have an air source heat pump. that then comes down to whether pump. that then comes down to whether you ve got space outdoors. it whether you ve got space outdoors. it can whether you ve got space outdoors. it can be whether you ve got space outdoors. it can be mounted on the wall and they don t it can be mounted on the wall and they don t have to sit on the floor on the they don t have to sit on the floor on the balcon