Cold reality for poorest households
The Northern Ireland Assembly has been told that a growing number of households have no choice but to purchase 20 litre drums of oil that are significantly more expensive per litre than buying in bulk.
BBC's consumer correspondent Martin Cassidy has been calculating what that means at today's home heating oil prices.
So what are the relative costs?
A cash and carry fuel supplier in Belfast is currently selling 20 litre drums of home heating oil at £20. Our first calculation is a nice simple one.
Buying oil in drums works out at an even £1 per litre.
The same company will also make a bulk delivery of oil to your home. The minimum delivery is 200 litres and the price is currently £157.50. That works out at 78p a litre.
For consumers who can afford to buy larger quantities the savings are even bigger.
A delivery of 500 litres is currently available at just over 60p a litre while a householder ordering 900 litres can expect to pay just over 58p per litre.
Now lets compare the annual heating oil cost for a household which relies on buying 20 litre oil drums with homes which can afford to purchase oil in larger volumes.
Assuming annual oil usage of 2760 litres, the relative annual costs look like this:
The comparison shows a yawning gap in annual heating costs.
Not surprisingly the household relying on buying its heating oil in 20 litre drums is paying a lot more for fuel.
Compared to buying in 200 litre amounts, the extra annual cost works out at £608 a year or almost £12 per week.
And as the ability of the household to afford to order larger volumes increases, so the savings increase for the more affluent consumers.
At its most stark, the annual difference is £1160 which works out at over £22 a week.