Manual kilns have similar controls to ovens, with a dial you turn yourself to heat the kiln up. This means that you have to watch manual kilns during the firing process to ensure they remain at the right temperature for the process you are trying to achieve. You will also need to use an external timer to ensure you don't leave the contents of the kiln firing for too long or turn down the temperature before your items are ready. Digital kilns, on the other hand, allow users to pre-program time and temperature settings so you can leave the contents firing while you get on with something else.
Just as you have to monitor a manually controlled kiln, you will also have to adjust the temperature every few minutes as the internal heat rises and cools. Digital kilns can regulate the internal temperature using their electrical monitoring and adjustment systems.
Manual kilns require users to monitor and initiate the cooling process themselves, whereas digital kilns will begin the cooling and annealing process once the pre-set time is up. However, according to online magazine Ceramic Industry, all kilns, whether manual or digital, need someone to monitor their shut-off at the end of the firing process. Although you can specify a shut-off time with digital kilns, this isn't always reliable and it is safer to supervise it yourself.
Kiln manufacturer Cress Kilns reports that digital kilns cost around $200 more than manual kilns. You might also need to repair digital kilns more often, as their electrical circuitry can be exposed to the heat from the kiln. However, digital kilns can save users a lot of time and effort compared to the monitoring that is involved with using a manual kiln.