Iced up deep freezers

[Segilla]

I can see that icing caused by leaving door open, opening door etc is not good, but once the ice is in place how can the motor be said to have to work harder, when the contents are effectively iced up anyway

[ACtheTROLL]

because Ice is cold because it's cooled.
water releases heat (or a lack of heat) slower than air - it's effectively an insulator
and the case insulation isn't perfect (switch off and see!)

so.... the cold has to penetrate the ice (I know ... it's a little Zen!) which is being insulated by a layer of melting water caused by the external temperature and the "hot" new items.
Once the item is frozen it does try to stay that way

it's like a coat ....

[heathfield]

In other words, the reduction in temperature from the cooling coils has to further cool all that ice before passing through it to begin cooling the rest of the compartment