Oil more than Electric
We're all aware, painfully, how much the cost heating oil has increased but are we all aware that it is now more than electric. Current price is near 60p/l (ex VAT) where as cheapest E7 night time is 5.2p. Heating oil is 10.35 kWhr/l which means you need a condensing boiler (93% efficiency) and oil at 50p/l to beat that.
The table for oil at 60/55/50p/l in a boiler with 84% efficiency (a recent non-condensing) or 93% (a recent condensing) is:
| 84% | 93% | |
|---|---|---|
| 60p/l | 6.90p | 6.23p |
| 55p/l | 6.33p | 5.71p |
| 50p/l | 5.75p | 5.19p |
The cheapest current price of Economy 7 night time electric is 5.2p/kWhr. So oil would need to be 50p/l and the boiler be a new condensing model to equal the cost of E7 night time electric.
However, it's not quite a simple as that. E7 daytime electric is more expensive so you need to have 21% (at the moment, depends on prices and supplier) night time usage to break even. And E7 is not as controllable as oil. But there is certainly scope to reduce oil consumption by using some E7 to warm the house in the morning and heating water over night. That's before considering adding one or more storage heaters for base load. E7 night is typically 00:30 to 07:30 (01:30 to 08:30 in summertime). Oil heating could then just be used for the evening time or for topping up the base load.
Pay back is quite quick as it doesn't cost much to swap to E7 unlike more dramatic changes. Taking hot water as 1 l oil/day, 9kWhr/day, is £171 E7, £200 oil (55p/l), and that's just the hot water part.