In short
The question usually comes from someone who has just bought a house with an Aga in it, or who is pricing one up and has heard the word “constant”. The short answer is that a traditional Aga is built to stay on, and most of the people who own one keep it on, because the cooker only works the way it does by staying hot. It does not have to be on. You can switch it off tonight if you want to. But switching off has a cost of its own, which is a cold kitchen and a cooker that takes most of a day to come back, and that cost is what decides the question for most owners.
Why a traditional Aga stays on
An Aga is a heat-storage cooker. A small, steady heat source, an oil burner, a gas burner or an electric element, keeps several hundred kilograms of cast iron at temperature all the time. The ovens and the hotplates draw on that stored heat. That is why the ovens have no dials: the roasting oven is at roasting temperature and the simmering oven is at simmering temperature because the iron around them is, and it stays that way whether you cook or not. Our how to use an Aga guide explains the zones.
The consequence is that there is no “on for dinner”. If the cooker is cold at six o’clock, dinner is not coming out of it. Warming the iron through from cold takes hours, which is also why switching off for a night saves nothing: the fuel saved overnight is spent heating the mass again in the morning.
What leaving it on costs
The standing cost depends on the fuel. At the prices on our running costs page in late 2026, for a 2-oven Aga:
| Cooker | A week |
|---|---|
| Oil, about 40 litres of kerosene at 118.4p | £47.36 |
| 13 amp electric, standard tariff | £57.90 |
Heating oil has risen from about 61p to over 118p a litre including VAT during 2026, so an oil Aga costs nearly double what it did in January. That is the figure that has more owners asking whether it has to be on at all.
When it is worth switching off
Summer
Roughly 4 in 10 Aga owners switch off for the summer; the rest run all year, often because the Aga also heats the kitchen and dries the washing. On oil, switching off for two months saves several hundred pounds. The trade is that you need something else to cook on, and the cooker needs a proper relight at the end of it. Our how to turn off an Aga guide covers the shutdown steps for each fuel.
Holidays
For a long weekend, leave it on. For a fortnight or more, switch an oil or gas Aga off before you go. Let it cool completely, which takes at least 12 hours, and never relight an oil burner while the cooker is still hot.
Before a service
An engineer needs the cooker cold, so switch off at least 12 hours before a service. That is the one time every owner turns the Aga off.
The alternative: an Aga that is on when you want it
This is where the question has changed in the last few years. An electric conversion replaces the oil or gas burner with independent elements in each oven and under each hotplate, each with its own control and timer. The cooker is the same cast iron Aga and cooks the same way, but it no longer has to be on all the time, because it no longer takes hours to warm up: the published heat-up time for the top oven is 35 to 45 minutes depending on the system.
From the ElectricKit figures on our running costs page, a 2-oven Aga at the Ofgem rate of 26.32p a kWh costs:
| How it is run | A day | A month |
|---|---|---|
| Always ready to cook, both hobs and both ovens on around the clock | £8.26 | £251 |
| Main oven kept hot, one hob on | £5.23 | £159 |
| Oven turned down to 100°C between meals | £4.13 | £126 |
| One timed cooking session a day | £0.73 | £22 |
A 4-oven conversion runs from £9.92 a day always on to £1.07 a day for one timed session. The point is not that everyone will run their Aga for 73p a day. It is that the choice is yours, each day, which a traditional Aga never offers. Left on around the clock, a converted 2-oven costs about the same as the 13 amp Aga it replaces; turned down between meals, it costs a fraction. Our electric conversion page explains the systems, and eControl against ElectricKit compares the two.
What “on” means on each fuel
- Oil. A burner at the base of the cooker runs continuously, regulated by a thermostat that keeps the cooker at its set heat. It uses fuel around the clock, and it must be fully cold before it is relit.
- Gas. The same arrangement with a gas burner, and the same thermostat. Gas is cheaper than oil at today’s prices, but the cooker still burns fuel whether or not anyone is cooking.
- 13 amp electric. An element on a thermostat, drawing from the mains through the day at standard rate. The simplest to switch off and on, but the dearest to leave on.
Some owners turn the thermostat down a notch in milder weather rather than switching off. The ovens run cooler and the saving is modest. If you want to try it, ask us first: a cooker run too low for long can soot up or struggle to reach roasting temperature.
The kitchen itself
Part of the honest answer is that an Aga heats the room as well as the food. In a stone farmhouse kitchen in the Dales, that background warmth from October to April is the reason the cooker is there, and it does the drying too. Owners who switch off in summer are usually the ones whose kitchens get too warm; owners who keep it on are usually the ones whose kitchens never do. If yours is a modern, well-insulated kitchen, the warmth is worth less to you and the case for switching off, or converting, is stronger.
So, does it have to be on?
- A traditional Aga: designed to stay on, and in practice it stays on from autumn to spring in nearly every home that has one. Switching off is for summer, long holidays and the day before a service.
- A converted Aga: on when you want it, off when you do not, with each oven and hotplate under its own control.
If you have inherited an Aga and the standing cost worries you, the answer is rarely to leave it cold. It is either to run it through the winter and switch off in summer, or to convert it and run it on your terms.
Frequently asked questions
Does an Aga have to be on all the time?
A traditional oil, gas or 13 amp electric Aga is designed to stay on. It is a heat-storage cooker: the burner or element keeps a large mass of cast iron at temperature, and the ovens and hotplates draw on that stored heat. It does not have to be on, and it can be switched off at any time, but once off it takes at least 12 hours to cool fully and the best part of a day to come back to cooking temperature, so it is not a cooker you turn on for dinner.
Can I turn my Aga off at night?
Not usefully, on a traditional model. The cooker would not be back to temperature by morning, and the fuel saved overnight is spent heating the iron again. A converted Aga with ElectricKit or eControl is different: each oven and hotplate has its own control, so you can switch off at night and have the top oven at roasting temperature within about 35 to 45 minutes of switching it back on.
Should I turn my Aga off in the summer?
Roughly 4 in 10 owners do, and 6 in 10 run their cooker all year for the warmth and the always-ready ovens. On an oil or gas Aga the summer saving is real: a 2-oven oil model burns about 40 litres of kerosene a week, which is £47.36 at 118.4p a litre, so two months off saves several hundred pounds. Weigh that against a kitchen with no cooker unless you have a second one.
How much does it cost to leave an Aga on?
At late 2026 prices, a 2-oven oil Aga costs about £47.36 a week and a 2-oven 13 amp electric Aga £57.90 a week on a standard tariff. A 2-oven Aga converted with ElectricKit costs from £8.26 a day with everything on around the clock down to £0.73 a day for one timed cooking session, at the Ofgem rate of 26.32p a kWh.
Should I turn my Aga off when I go on holiday?
For a long weekend, most owners leave it on; the saving is small and the cooker is ready when you return. For a fortnight or longer, switching an oil or gas Aga off is worth doing. Follow the shutdown steps for your fuel, let it cool, and never relight an oil burner while it is still hot.
Is there an Aga that is not on all the time?
Yes. An electric conversion gives every oven and hotplate its own control and its own timer, so the cooker is only on when you want it, and the published heat-up time for the top oven is 35 to 45 minutes. It is the same cast iron cooker, cooking the same way, without the standing cost.
Want your Aga on your terms?
We convert oil, gas and electric Agas to ElectricKit and eControl across Yorkshire, Cumbria and the North East, and we service and refurbish traditional models that are staying as they are. Call 01748 811030 or request a callback below.