In short: In a gas oven the heat comes from a burner at the bottom; in an electric oven from elements above and below. Hence the difference: a gas oven bakes less evenly and heats the base harder, while an electric one is steadier and holds temperature more precisely.
How each one heats
Two types dominate: gas and electric. The first is heated by a gas burner, the second by electric elements. In a gas oven the heat source is usually only at the bottom, whereas an electric oven has elements above and below.
That single structural difference explains almost everything else about how they behave.
What it means in practice
Gas. The base browns first and the top lags behind. Bread and pizza benefit; delicate sponges and meringues suffer. A tray on the middle shelf with an empty tray below as a shield evens things out considerably.
Electric. More even and more accurate, with better control at low temperatures — which is what meringue and slow-baked cheesecake need.
Convection
A fan levels the temperature and speeds baking, but it also dries the surface. Turn it off for sponge; turn it on for meringue and laminated pastry, where dry heat is the point.
Trust the dial less
Built-in thermostats are frequently out by 10–30 °C, and there is no way to know without a separate oven thermometer. Measure once, note the offset and treat that as your oven’s normal.
Frequently asked questions
Why does my gas oven burn the bottom
The heat source is only at the bottom. Use the middle shelf and put an empty tray below as a shield.
Should I use convection
It evens temperature and speeds things up but dries the surface. Off for sponge, on for meringue and laminated pastry.
How far out is the oven dial
Often by 10–30 °C. Check with a separate oven thermometer and work to the offset you measure.