Combustion appliances or mechanical systems, including fireplaces, gas stoves and gas heating systems, produce by-products that need to be removed using a system of vents or flues known as an exhaust system.
To function properly, exhaust systems must be free of holes, cracks or rust. They should be installed so that combustion products are carried out of the house before cooling and condensation occurs. (Warm gas is more easily moved from one place to another.)
Proper ventilation also requires enough fresh air entering the system to prevent backdrafting. Backdrafting occurs when the combustion gases flow back indoors instead of moving outdoors through the vent or flue. High air pressure outside the house, low air pressure inside the house or improper appliance operation can sometimes impact the effectiveness of vent systems.
Inspecting all visibly accessible parts of exhaust venting systems and testing for backdrafting is part of a general property inspection. A qualified inspector will evaluate the condition of the heating system, the location of master switches, functionality, the type of energy source used and the method of conducting heat throughout the home or business.