Some people would say the four words are synonymous. Others might distinguish in this way:
> Updating simply brings a few things up to date, such as new water-saving faucets or energy-efficient appliances, or new energy-efficient windows.
> Remodeling would be moving or removing walls, building an addition or making other major changes in a house to make it more comfortable, more functional, more energy-efficient or more marketable.
> Renovation means to make new again, thus a remodel that makes the home or some part of the home new again. You might do an electrical system renovation, for example.
> Restoring means returning the house to its original condition, usually with reference to older and historic homes.