Domestic Appliance Forum

MY fridge freezer is using around 900 kw/year when it should be around 500Kwh. Although not running conituously it does seem to run alot even when temperature are steady at -18C (freezer), 5C for fridge.
I have checked all the fridge/freezer and condensor fans are working. All defrosts heaters work and no ice build up. door seals are in good condition.
There are no fault codes.
Also I have cleaned all the condensor coils of dust no improvement. Could it be gas is low if so how to check?
What else can I check