Can a Generac unit be configured to ONLY power essential areas of the home rather than the entire home, ie refrigerator, minimal outlets?

I bought the 16K guardian generator. The store told me it would run the whole house. Electrician said it wasn’t big enough wattage so they wired only the essential things. Entire kitchen, loft where computer is, great room for electronics and a few essential lights and outlets. This works fine in average weather. Not big enough to include the furnace. Outlets do work in some rooms so I can use portsble heaters or ac if needed.