When choosing which stove you will require we must take into account;

The square footage
The season of use (winter/spring and fall)
The ceiling height
How well or not the space is insulated

Square footage

The Cub is designed for spaces up to 100-200 sq ft.
The Grizzly is designed to heat up to 200-400 sq ft.

Season

The Grizzly is more of our winter model
The Cub is best suited for spring and fall

Ceiling height

The higher the ceilings the more volume you have to heat, which will play a role in which stove should be selected.

Insulation

Heat retention is another important factor. Spaces that are very well insulated will keep the heat much better than a place that is poorly insulated. Windows can also play a role in how much heat is lost. Vans for example which are not terribly well sealed can lose heat through the cracks of the doors and window. And a school bus would have a similar issue due to the amount of windows they normally have.

The Grizzly stove is the stove suited for most applications, unless used in spring and fall only, with a space that is very well insulated and has low ceilings.