Prefabricated fireplaces
are usually made of metal and have metal vents (chimneys). Prefab units
(fire box and chimney) which were cast of cement type materials and
trucked to the site, were available at one time in some areas of the
country. These have been found to be quite durable if installed
correctly. The heat exchanger in the heater on the left is not possible
to review. Insufficient visibility is the major reason heat exchangers
are not generally inspected by inspection companies.