New Freezer v old appliances

champ_de_porter

I currently have a standard freezer 4' and an under counter fridge both very old at least 15 years infact the fridge is about 20, the fridge isnt big enough so we are also using a beer fridge, my question is if I replaced all these with say a side by side american style fridge freezer would I expect to reduce my monthy electricity output and if so by approx how much? As all are working well enough I need to be convinced I will something by buying new thanks