IMVHO you can't get other answer than: try it an measure...
Energy consumption does not depend ONLY by the target temp but ALSO by the external temp, or the Δt between them, the level of insulation of your house, how airtight (and eventually with what kind of VMC you have) etc even approximated answers can't be much meaningful.
What I can testify having switched from a "classic" (low insulation, no good vent etc) home to a new "class A" (french BBC to be more precise) one is that insulation, ventilation, good passive heating (windows on south, well exposed to the low winter Sun, but covered for the high summer Sun) does work enormously well. Or, the "Green New Deal" do have some tangible basis, unfortunately it's not much practical in most of the EU, at least in cities and in general in dense area, to rebuild anything accordingly, especially in a short term.
If you want to save money and have a better life, my real suggestion is: flee the city, looking for a home you can afford, one in a reasonably served place and do your best to telework. You like it or not that's the direction we heading, so the better you can get in this direction the batter you'll get paid off in the future... Other "emergency gimmick" do not really work, if they it's too little for too much effort, or they are simple raw cuts like "to save money do not go on holidays" witch might work in some short term terms, but are not much sustainable in the long run...
Energy consumption does not depend ONLY by the target temp but ALSO by the external temp, or the Δt between them, the level of insulation of your house, how airtight (and eventually with what kind of VMC you have) etc even approximated answers can't be much meaningful.
What I can testify having switched from a "classic" (low insulation, no good vent etc) home to a new "class A" (french BBC to be more precise) one is that insulation, ventilation, good passive heating (windows on south, well exposed to the low winter Sun, but covered for the high summer Sun) does work enormously well. Or, the "Green New Deal" do have some tangible basis, unfortunately it's not much practical in most of the EU, at least in cities and in general in dense area, to rebuild anything accordingly, especially in a short term.
If you want to save money and have a better life, my real suggestion is: flee the city, looking for a home you can afford, one in a reasonably served place and do your best to telework. You like it or not that's the direction we heading, so the better you can get in this direction the batter you'll get paid off in the future... Other "emergency gimmick" do not really work, if they it's too little for too much effort, or they are simple raw cuts like "to save money do not go on holidays" witch might work in some short term terms, but are not much sustainable in the long run...