An electric or oil Aga???

It seems to me that an electric Aga alongside Solar Power is a smart way to go although it can only realistically supplement the power utility and reduce costs. The price of oil can only go one way.

We have an oil-fired 4 door Aga with water heating (OEB 90 in Aga speak). We have a 210 litre hot water tank.

Aga quote its consumption as about 70 litres / week, and that's about right taken as an average over the year if you run it as it is intended to be run.

Being reasonably modern (installed in 1997) the burner is thermostatically controlled with two settings: "high fire", which means blazing away, and "low fire", which means ticking over.

Under the normal Aga system the thermostat swaps between the two settings, and it probably spends about 50% of the time on each. Although obviously it is to some extent driven by the demand you place on it, ie cooking and using hot water, this high/low switching cycle holds true 24 hours a day.

The thermostatic controls are electric, so we have fitted a timer (£5 from Tesco) that turns off the mains between 10pm and 5:30am, meaning that it is on low fire for the full overnight period. This means that its heat drops off overnight, and it has to run on high fire for an extended period when it wakes up at 5:30am in the morning but, by and large, it is up to temperature in time for breakfast.

This has reduced the oil consumption from 70 litres / week to about 55 litres / week, these figures being based on several years worth of consumption, so if your oil-fired Aga has:

+ electrically driven thermostatic controls

and (this is crucial)

+ a good flue

I would recommend this approach.

If you have problems with flues, or your Aga's burner gums up easily, then don't even think about it!


So to return to the original question, "which is better: oil or electric", I hope these figures help.

Oil is still expensive, around 60p/litre at the time of writing in March 2012, so our Aga uses over £30 worth a week. But on the other hand it cooks everything, provides all our hot water and also heats about 1/3rd of the house.

From what I can make out there are two electric Aga alternatives:

(1) Night storage. People I know who have one, that doesn't heat water, give a cost of about £30+/week.

(2) Turned on when needed electric cooker. Obviously the cost depends on how much you use it. It seems to me to be a fantastically expensive solution for what is really just an electric cooker ...


Certainly in this old Devon farmhouse having a constant source of heat through the winter months keeps it dry and makes the kitchen a warm and welcoming place. Boy do we notice when it is turned off for servicing!

(On that note running on low fire at night will increase slightly the rate at which the burner gums up. Prior to doing this our Aga would do about 10 - 11 months before conking out, now it is about 8 - 9 months. A service is about £75, which needs to be added to the running cost, unless you do it yourself - it's an easy but messy job.)

There is another way of looking at the costs, and that is to consider and price the energy content of the fuel.

Aga oil is called 28 second kerosene and it contains about 10 kWh of energy per litre. An electrical "unit" is 1kWh, so a litre of kerosene produces the same amount of heat as 10 units of electricity.

At today's prices of ~60p/litre that means 1 unit of heat from oil costs about 6p. For comparison electricity is currently in the range 10p to 12p during the day, and 5p to 6p overnight if you have a white meter.

This explains why the "night storage heater" Aga costs more or less the same to run as an oil fired one.

I see the original thread was 2008, and it's now 2012, but I hope this helps anyone who has come across the original question.