Consider every plug-in device that is on 24x7 (smoke detectors, central vac, battery chargers, clocks, ...) sucks about 5W or $5/yr. I've not found old fridges bad. My 20 year old all-fridge only uses about 30% more energy than a modern all fridge. My 20 year old fridge and freezer use the same power as most "energy star" fridges at the time did. Now we use an upright freezer converted to a fridge - with 1/2 of the energy draw of the best energy star fridge all done for the cost of a $30 thermostat. Pay particular attention to the vampire/standby energy use of appliances at purchase time. EU spec ones are 1W or less. Microwave ovens are 2W to 10W - when not being used and that power draw will exceed, over a year, the actual power used to heat foods.
What's can a family of 4 do with a 1991 vintage home? We're around $35/mo electricity, $400/yr in gas for heating and around 3.5 cu-meters of water per year. My experience is that changing your habits will make things like solar/on-demand water heaters uneconomical. We spend $80/yr (19 gallon electric water tank) heating water ($20/yr of that is keeping the tank warm). Paying $2500 for a solar water heater AND then still needing to save perhaps $50 per year is insane.