The basic home warranty includes the main home systems and some appliances. Most companies cover sanitary, electrical, heating systems as well as refrigerators, dishwashers and microwave ovens. Some calculate additional coverage for appliances such as washing machines and dryers. A home warranty company covers the cost of repairing or replacing the system or appliance, as long as it has collapsed due to normal wear and tear. If the system or appliance is down because it has not been serviced (the water heater has not been rinsed or the evaporation coils in the refrigerator have not been cleaned), most home warranty contracts do not cover the cost of repair or replacement. There are home warranties to repair or replace old worn systems that have been properly maintained by the owner.