Parts of an Aga Cooker: A Glossary of Every Component, Plate and Oven

In Short…

The main parts of an Aga cooker are: the boiling plate (left, fast heat) and simmering plate (right, gentle heat) on top, the roasting oven (hottest), baking oven (medium), simmering oven (low) and warming oven (lowest, on 4-oven models) inside, and the lids, doors, hinges, flue, thermometer, plinth and burner or heating element as the supporting structure. This guide names every part and explains what each is for.

At a glance: every named part of a 3 or 4 oven Aga

• Top of the cooker: boiling plate, simmering plate, hot lids (chrome domed), hinges, flue collar, rail
• Front of the cooker: roasting oven door, baking oven door, simmering oven door, warming oven door (4-oven only), front panels, door surrounds, plinth
• Inside each oven: oven shelves, runners, cold shelf, oven liner, the cast-iron walls themselves
• Heat source: burner pot (oil), gas burner (gas), electric heating elements (electric or converted models), control box (oil/gas), thermostat
• Indicators: mercury thermometer, control dial, electric control panel, app on modern conversions

Key facts

• The Aga cooker was invented in 1922 by Nobel Prize-winning Swedish physicist Gustaf Dalén as a single-burner heat-storage cooker.
• The original Aga was designed to burn coal or anthracite. Modern Agas run on oil, gas, electric or solid fuel, with electric models becoming the dominant choice in the UK.
• A standard Aga has two cast-iron hotplates and between two and five ovens, depending on the model.
• The cast-iron core of an Aga can last for decades with proper care. Most refurbishment work focuses on the panels, enamel, controls and heating elements rather than the cast iron itself.

Definitions

• Cast-iron core. The structural heart of an Aga. Heat from the burner or elements is absorbed by the cast iron and radiated steadily to the ovens and hotplates.
• Hotplate. The heated cast-iron disc on top of the cooker. Always two: a high-heat boiling plate and a lower-heat simmering plate.
• Lid. The hinged chrome dome that covers each hotplate. Closed when not in use to retain heat.
• Roasting oven. The hottest oven (typically 240°C or above), positioned directly under the boiling plate.
• Simmering oven. The lowest-heat oven (around 100–135°C), used for slow cooking, casseroles and meringues.
• Plinth. The base panel at the front of the cooker, often adjustable on modern conversions.
• Flue. The chimney pipe that exhausts combustion gases on oil and gas models. Not required on electric Agas.

The top of the cooker

Boiling plate (left hotplate)

The high-temperature hotplate, used for rapid boiling, fast frying, grilling and the famous criss-cross toast. Surface temperature reaches around 240°C in operation. Always use the chrome lid to retain heat when not in use.

Simmering plate (right hotplate)

The lower-temperature hotplate at around 130°C, used for gentle simmering, sauces, milk, pancakes and toasted sandwiches (with non-stick liners). The simmering plate doubles as a flat-iron-style griddle.

Hot lids (chrome covers)

The polished chrome domes over each hotplate. Their job is to retain heat when the plate is not in use. Open lids waste energy and reduce overall cooker efficiency. The lid handles can collect grease over time and benefit from professional cleaning during a refurbishment.

Flue collar and rail

The flue collar is the visible top of the chimney pipe on oil and gas models. The brass rail across the front of the cooker is decorative and can also be used as a tea-towel rail.

Thermometer

The dial gauge usually found on the front-right corner of the cooker. It indicates whether the cooker is at the correct operating temperature. An under-reading thermometer is one of the most common causes of “my Aga is not cooking the way it used to” service calls.

The front of the cooker

Roasting oven door

The top-right oven door, with the hottest oven behind it. Heavy, hinged, with a viewing window on some models.

Baking oven door (3-oven and 4-oven only)

The bottom-right or bottom-left door, depending on model layout. The baking oven sits at moderate temperatures suitable for cakes, biscuits, fish and lighter pastry.

Simmering oven door

The bottom door, behind which the slow-cook oven sits. Used for stews, slow roasts, meringues and overnight casseroles.

Warming oven door (4-oven only)

The lowest-temperature oven (around 80°C), used for warming plates, proving dough and gentle holding of cooked food.

Front panels and door surrounds

The enamelled panels that form the visible face of the cooker. Available in over 40 colours on most modern Agas. Front panel re-enamelling is one of the most transformative refurbishments we do at John Wray. See our Aga re-enamelling service for the full colour range.

Plinth

The base panel that sits between the floor and the cast-iron body. Usually 60mm to 75mm tall on modern installations. Every John Wray conversion includes a 60mm adjustable plinth as standard.

The ovens explained

Roasting oven

• Position: top, under the boiling plate
• Temperature: approximately 240°C
• Best for: roasting meat, baking potatoes, Yorkshire puddings, pizza, pastry, scones, anything that needs a hot, fast oven

Baking oven (3-oven and 4-oven models)

• Position: bottom-left or bottom-right depending on model
• Temperature: approximately 180°C
• Best for: cakes, biscuits, muffins, soufflés, crumbles and fish

Simmering oven

• Position: bottom right (3-oven) or middle (4-oven)
• Temperature: approximately 100–135°C
• Best for: casseroles, slow-roasting, steaming vegetables, fruit cake, cheesecakes and meringues

Warming oven (4-oven only)

• Position: lowest in 4-oven layouts
• Temperature: approximately 80°C
• Best for: warming plates, proving bread dough, holding cooked food

For full temperature charts and recipe conversions, see our Aga oven temperature guide.

Inside each oven

Oven shelves

Heavy, perforated cast-iron racks that slot into the oven runners. Aga shelves are heavier than conventional oven shelves and have specific cooking properties.

Runners

The rails along each side of the oven cavity that hold the shelves at fixed heights. Most Aga ovens have four runner positions.

Cold shelf

A thicker shelf used as a physical barrier to slow heat at the top of the roasting oven. Useful when the top of the oven would over-brown an item.

Oven liner

The flat enamelled or aluminium tray that protects the floor of each oven from spills. Easier to remove and clean than the cast-iron oven floor itself.

The heat source

Oil burner pot (oil models)

The cast-iron pot beneath the cooker where vaporising oil burns. The burner is housed behind the inner door and accessed for lighting and cleaning. See our oil-fired Aga lighting guide for the full burner layout.

Gas burner (gas models)

A natural-gas or LPG burner with a pilot light system. Controlled by the front-mounted thermostat.

Electric heating elements (electric and converted models)

Modern electric Agas use independent elements per oven and per hotplate, allowing zoned, programmable control that the original heat-storage models cannot offer. Conversion systems include ElectricKit Classic, ElectricKit Advanced, eControl Series X and eControl Series X-Squared, all of which we fit at John Wray. Compare them on our ElectricKit Advanced vs eControl Series X-Squared page.

Control box (oil and gas)

The wall-mounted unit that manages oil or gas flow to the burner. Includes a reset lever and, on oil models, a fire valve.

Thermostat

The component that regulates burner output to maintain operating temperature. Located behind the front panel on oil and gas models, integrated into the touchscreen on electric conversions.

Common accessories often called “parts”

• Roasting tin sized to the oven runners
• Bain-marie for water-bath cooking
• Toaster for the criss-cross toast trick
• Bake-O-Glide non-stick liner sheets
• Kettle designed to sit flat on the simmering plate
• Hob covers that protect lids when in use
• Drying rack that fits across the lid surfaces

These are not technically cooker parts but live alongside the cooker and are often listed in spare-parts catalogues.

Frequently asked questions

How many ovens does a standard Aga have?
Two, three, four or five. The 2-oven model has a roasting oven and a simmering oven. The 4-oven adds a baking oven and a warming oven. The 5-oven adds a second baking or warming oven.

What is the cold shelf for?
The cold shelf is a heavy cast-iron shelf used as a heat barrier in the roasting oven, slowing browning at the top so items lower down can finish cooking.

Why are the ovens different temperatures?
The Aga’s heat-storage core radiates heat from a single source. Oven temperatures are designed to suit different cooking tasks rather than being independently set. Modern electric conversions break this rule and allow each oven to be set independently.

What’s the difference between the boiling plate and the simmering plate?
The boiling plate runs at around 240°C for fast boiling and high-heat cooking. The simmering plate runs at around 130°C for gentler cooking. Both are cast iron, both have chrome lids, but their internal heating differs.

Can I replace individual parts of an Aga?
Yes. Doors, hinges, lids, thermometers, oven liners, plinths, panels and burners can all be replaced or restored. A full Aga refurbishment covers the lot.

What’s the part of the Aga most likely to need attention?
The thermometer (small, common service item), the oil burner pot on oil models (carbon build-up), the lid handles (grease accumulation) and the front enamel (chips and crazing on older cookers).

How often does an Aga need servicing?
Annually for oil and gas models. Electric conversions need no scheduled servicing, only periodic checks if performance changes.

Where can I see the parts in person?
Our showroom at Swale Lodge, Scorton Road, Brompton on Swale, Richmond, North Yorkshire DL10 7EQ has cookers running and cookers stripped to their cast iron, all by appointment. Call 01748 811030 or book a showroom appointment.