A home warranty is a one year service contract, which helps protect homeowners against the cost of unexpected repair or replacement of major systems and appliances that break down due to normal wear and tear. A home warranty is a one year service contract, which helps protect homeowners against the cost of unexpected repair or replacement of major systems and appliances that break down due to normal wear and tear. A home warranty is a one year service contract, which helps protect homeowners against the cost of unexpected repair or replacement of major systems and appliances that break down due to normal wear and tear.