Single ovens can be fitted under a bench, but models with separate warming drawers or double ovens are too tall and have to be fitted into a wall unit.

If you need extra oven volume, consider a 900mm wide single oven. If you do a lot of single-shelf cooking (cakes and delicate items like quiches and custard tarts) these extra-wide ovens are useful because they let you fit two cake tins side-by-side. But they have wider and larger trays that become very heavy when fully loaded. The trays and shelves are also awkward to clean in a standard-sized kitchen sink.

Double ovens are perfect for people who like to cook different things at the same time. They’re two separate ovens stacked on top of one another, each with its own door and cooking controls. The secondary oven is usually about half the height and volume of the main oven.

You can bake in one oven and grill in the other, or bake two things that require different temperatures and functions. You won’t usually save time heating a secondary oven instead of the main one. But you may save a little energy: most secondary ovens use a little less energy.

Door openings

Side-opening doors can be really useful if your oven is positioned above bench height – you can reach in easily to take out food. Even at a lower position, it means you avoid having to lean over a hot oven door. And it's also more convenient for wheelchair users (provided the oven's placed at a sensible height).

Your kitchen layout may leave you no option but to install a side-opening oven at below hob or bench height. If so, check how the door locks into place. One central attachment point can mean you'll pull on the top of the door to open it, and the door may eventually distort. Attachment points at the top and bottom of the door are better as they force you to pull the door from the middle.

Ovens with a side-opening door need to be installed dead level, otherwise the door can swing back on to you and maybe give you a serious burn.

A downward-opening door is more suitable for under-bench ovens, as the door prevents your legs coming in contact with the hot oven shelves at this level. Some people might prefer a downward-opening door as it can be used for resting heavier baking dishes on.

Also, for doors

Check it's light and easy to open, and that it stays open in any position (without falling/swinging fully open or slamming shut).
Look for a large enough window that gives a clear view inside.

The oven

Is usable space important? Then measure the usable internal dimensions yourself - don't rely on the stated capacity. Take along your largest baking dish with you to the store and check whether it will fit.
Make sure the bulbs for the interior lights are easy to replace (some require a service call).
Check that the shelves have safety stops to prevent them being pulled out accidentally. And make sure the shelves don't slope down when pulled out – especially with the weight of a heavy dish. Sloping down can make food spill; the container may even go sailing off.
Look for a good range of shelf positions. Three or more shelves may be handy, especially if you often cook several items at the same time.
Aim for moulded runners rather than detachable ones – they're easier to clean.

Grill

Look for a "smokeless" grill tray that traps fat and oil below it (this reduces the amount of burning and spattering from the fat or oil). Also make sure that the tray slides easily, with a safety mechanism that stops it from pulling right out – but that it comes out far enough to let you deal with food at the back of it.
Aim for an element that's set high into the ceiling or has a shield in front, so that it can't easily come into contact with your fingers (this is particularly important if the oven's under the bench).
Check there are at least two grill-tray heights.

Functions

Multifunction ovens allow you to use the oven with or without the fan, or use a combination of fan and elements.

Fan baking distributes heat evenly, so is good when cooking on several racks. Using the fan should allow food to cook faster and at a lower temperature setting. But some dishes will not necessarily cook better in fan mode. Foods like baked puddings are sensitive to the air movement caused by the fan.
Fan-forced is where there is a fan and concealed heating element in the rear of the oven which blows hot air into the oven cavity. The top and bottom elements may also be used to speed heat-up times. Fan-forced baking is good for multi-shelf cooking.
Fan-assisted uses the fan to circulate heat from the top and bottom elements. It's good for single shelf cooking.
Fan grilling circulates heat from the grill element, achieving a result rather like rotisserie cooking. It's suitable for foods you might otherwise fry, such as sausages, and also for chicken pieces and kebabs.
Defrosting uses the fan without any heat, or at a low temperature. However, defrosting food slowly at a low heat is not recommended for food safety reasons – you're better to use a microwave or defrost food overnight in the fridge.
Part grill is an option on some wall ovens. This allows you to use only a small section of the grill for small servings.

Hassle-free cleaning?

For easy cleaning, a pyrolytic self-cleaning function is best – although catalytic liners also make cleaning easier.

Think about how often you use your oven and what you like to cook in it: an oven with pyrolytic self-cleaning will make life easier for those who often cook dishes that splatter oils or fats around the oven.

Pyrolytic cleaning

Ovens with pyrolytic cleaning have a special setting: the oven heats up to around 500°C, converting food residues into ash that you then wipe away. Most of the ovens have a light soil-clean (1.5 to 2 hours) and a heavy soil-clean (2.5 to 3 hours).

For safety reasons, the door automatically locks during the pyrolytic clean and is released only when the oven gets down to about 280°C. The outside of the oven is much hotter than usual while cleaning, so keep children out of the kitchen.

While pyrolytic cleaning sounds great, not all the hard work is done for you. All runners, shelves and other accessories need to be removed beforehand and cleaned separately – which can be difficult in some models. It's also worth cleaning off any coarse dirt first, and thoroughly cleaning the inside glass. And of course afterwards you have to remove the ash from the oven.

But while you still have to get your hands dirty, the pyrolytic function is chemical-free and it does thoroughly clean your oven – particularly in hard-to-reach places. We'd recommend it to anyone who can afford these types of ovens.

Catalytic liners

Some ovens have a self-cleaning surface known as a catalytic liner. This microporous coating absorbs fat splatters while the oven is cooking. While the liners protect the walls from fat splashes you still have to clean the doors, shelf supports, racks, and floor – but liners certainly make the job easier.

To get the best out of catalytic liners, regularly heat the empty oven for between 30 minutes to an hour (depending on the manufacturer's instructions). Then, when the oven’s cooled down, wipe it out with a damp cloth.

If they're properly cared for, the liners should last a long time – but they may eventually need replacing.