The easiest way is to cut the amount called for of each ingredient in half. Thus instead of one cup of chicken broth you would use one half cup of chicken broth. If you have a really small slow...
I suppose it depends on what you are comparing it to. All slow cookers are surely more efficient than my 1940s Wedgewood but a solar oven would beat a slow cooker.
Stab potatoes with fork. Wrap each in foil. Fill slow cooker with potatoes. Cover and cook on High 3--4 hours or until potatoes are tender. Do not add water.