han-grrl raises some very good points.

I recently read a reference to a study which showed that the amount of incidental exercise you do (laundry, housework, etc, etc) is also important for weight loss. Apparently this study showed that people who did very little incidental exercise during the day had greater difficulty losing weight.

So don't think of the vacuuming as a chore, think of it as part of your weight loss program.