We are in the process of purchasing a home with a gravity furnace and are concerned about several things. We would like to clarify your response above. Are you stating that if the gravity furnace is a forced air system and not a hot water system that it definitely needs to be replaced? If we choose to replace the gravity furnace, how safe is the removal procedure by a professional? Do they test all areas of the home after removal to ensure no risk of asbestos exposure? Thank you so much for your time and response.