Thats a piece of string question,so many variables,type of boiler(yes oil I know) size of burner,ammount of use,condition of boiler etc etc,only way to find out is to measure it over a given period of average use.
Looks like I have to buy 500litres of the stuff (£250 :shock: ) and was trying to get an idea of how long it might last..
If it were down to me I'd just throw extra layers on and leave the heating off
We have an open fire in the front room too so I would imagine it'd be on low just to take the chill off the rest of the house (we all like a cool - but not cold - bedroom) and a couple of tanks of hot water a day..
we have a relatively small boiler in work uses 3000l per week but yours won't use anything like that,It really is a case of suck it andsee,also make sure it has been recenly serviced with a new nozzle in the injector and that the oil pump on the burner is ok (after being emptied,needs a new filter and properly bleeding to make sure there's no water in the line,(anyone would think I was a heating engineer)
We lived in a cottage for 18 months whilst the flood damage was repaired at home and it had oil fired heating. It was 3 bed but a recent(ish) conversion of an old barn therefore it had pretty good insulation. I'd say it was cheaper using oil than the gas we use back at home. £450 worth lasted a harsh winter and well into the following autumn.
Keep checking the levels though. We ran out on the 23rd of December and went all Christmas and new year without heating or hot water until we could get a delivery. Thank goodness for the Aga!
Finally, keep it well padlocked at all times. The pikeys will love you if you don't.
According to earlier googling, oil has been the most economic fuel for about the last 8 years..
Going to be putting 500l of the stuff in at the start of December.. hoping it lasts a fair few months.. especially since we'll be running the open fire too. .
And also going to try for a budget account with a supplier too, a few are alleged to offer them without any interest etc..