How to Retrofit an Octopus Furnace

Gravity furnaces, sometimes called “octopus furnaces,” are an old type of gas-burning heater. These furnaces were used during the 1800s and 1900s. They’re referred to as octopus furnaces due to the several ducts that connect to the main heating unit. When an appliance is retrofitted, an element is added to it that it didn’t originally have. This way, an old appliance, like a gravity furnace, can be modernized and used in a contemporary household or building. When retrofitting any heating system, it’s not a case of one-size-fits-all; there are several options that need to be considered.

Heat source
Ducts
Insulation

Instructions

- 1
  Choose the heat source that will be used in the future; this depends on location and cost. Depending on the geographical area, options for gravity furnaces may include coal, oil, natural gas or wood. If the gravity furnace has been running on coal, it’s not necessary to continue using this fuel source if there are other less expensive sources available.
- 2
  Ask a contractor to look at the heating system, to check that all of the seals and joints on the system are intact. A contractor should also be able to determine if heat is escaping in any areas of the home; fixing these trouble spots will cut down on the heating bill.
- 3
  Replace any ducts that are letting heat escape.
- 4
  Replace asbestos insulation with modern insulation. The ducts and pipes of the gravity furnace should be insulated.

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