What is an octopus furnace?

Author: Jay Gerlach MD  |  Last update: Friday, August 22, 2025

An octopus furnace is an older type of heating system that was common in homes built before the mid-20th century. These furnaces are usually large, with a central furnace body and multiple ducts resembling tentacles, which is how they got their “octopus” nickname.

What kind of furnace was in Home Alone?

The official name for it is a coal-fired gravity hot air furnace—or, as we often call it, an “octopus furnace.” This furnace is pretty rare in homes today (and it's definitely not the best or most efficient way to heat your home).

What are the three types of furnaces?

In case of combustion type furnace, depending upon the kind of combustion, it can be broadly classified as oil fired, coal fired or gas fired.

Do octopus furnaces have filters?

They don't filter the air

A filter would prevent the air from circulating properly and drastically affect already-low efficiency. So octopus furnaces don't have filters.

What category is an octopus furnace?

Gravity Based Furnaces – Are they an issue? Although it does not happen very frequently, every once in a while, I run into an old gravity-based furnace when completing a home inspection. These furnaces are also referred to “Octopus” furnaces, because of how the ducting come out of the unit.

Gravity Furnace aka Octopus Furnace still in use!

When did octopus furnaces stop being used?

An octopus furnace is an older type of heating system that was common in homes built before the mid-20th century.

What category does octopus fall under?

What is an octopus classified as? An octopus is classified under the phylum Mollusca and class Cephalopoda. They are invertebrate cephalopods with a high degree of intelligence and excellent visual acuity.

What is the inside of the octopus furnace?

The octopus furnace was a coal burning gravity hot air type. A gravity furnace heats the air and the hot air slowly rises through a duct system as hot air always rises. There was no fan to force the air on this model. Just blasts of very hot air naturally rising through the ducts.

When did they stop making gravity furnaces?

These antiquated furnaces were installed from the late 1800s to the mid-20th century and are still found in use in some older buildings.

Do octopus do boilers?

Still, it is possible to receive a completely free boiler with Octopus Energy, if you qualify for enough support under a scheme that they're a part of.

What is the best furnace brand?

The 5 Best Furnace Brands
  • Carrier Furnace: Best Warranty.
  • Lennox Furnace: Best Company Reputation.
  • Bryant Furnace: Best for Durability.
  • Trane Furnace: Most Years of Experience.
  • Amana Furnace: Best for Efficiency.

What kind of heater uses the least electricity?

If you want to save money on your heating costs, then an infrared heater is the best type of heater to choose. An infrared heater will use less electricity than any other type of heater, and so it will be cheaper to run. Not only that, but an infrared heater will also provide you with a more efficient form of heat.

What is an old furnace called?

Gravity Air Furnace Systems

Cool air returns to the furnace via a system of cold-air return ducts. The so-called "octopus" furnaces found in many older homes are gravity air furnaces. Gravity air systems are no longer installed, and the cost of maintaining them should be minimal.

Was Home Alone filmed inside a real house?

“Film sets must be large enough to have room for the camera, as well as the actors, in addition to the furniture,” explains Cauley, the movie's set decorator. The set team ultimately decided to build the entire interior of the home in the gymnasium of New Trier High School, also in Winnetka.

What did Kevin use to heat the doorknob?

What Kevin used was the heating element for an Electric Hibachi, which was used by sticking it in coals to heat them up for grilling. Kevin simply looped this around the inside doorknob, and due to conduction, the outside knob was also super-heated.

What is the heater in the basement called?

Furnace. Commonly referred to as “forced air systems,” furnaces are the most common heating systems found in homes. Air is heated in the furnace using gas, electric, propane or oil and then distributed throughout your home using ductwork and vents. You can find your furnace in the basement, attic, crawl space or closet ...

Are gas furnaces being phased out?

By 2030, the California Air Resources Board (CARB) has banned the sale of new gas furnaces and water heaters. This is an effort to push homeowners toward zero-emissions alternatives like electric furnaces, heat pumps, and electric water heaters. This initiative shows California's commitment to combating climate change.

What is the history of the octopus furnace?

Gravity furnaces are often nicknamed 'octopus' furnaces because of their multiple 'arms'. They date back to the late 1800's and early 1900's and were originally designed to burn coal but later switched to burn oil or natural gas.

Are floor furnaces still made?

They can still be fixed, but once the heat exchanger of this floor furnace (firebox) is ruptured, it must be converted to another type of heating unit. Floor furnaces are still manufactured, but they are the style that only serves a single room.

What is the black stuff inside octopus?

Their ink! Cephalopods use their ink to scare or distract predators so they can escape before being seen (or eaten). The ink is ejected from the ink sac within the cephalopod's body. The ink is made of melanin and mucus.

Do they still make fuel oil furnaces?

While natural gas models have become the most common type of furnace used in the United States, oil furnaces are still available and commonly found in the Northeast. An oil system heats your home in much the same way as a natural gas model.

Is the glass octopus real?

The glass octopus (Vitreledonella richardi) is a very rarely seen cephalopod found in tropical and subtropical waters around the world. The species gets its name from its nearly-transparent body—you can see straight through to the optic nerve, eyes and digestive tract.

How intelligent are octopuses?

They can complete puzzles, untie knots, open jars and toddler proof cases, and are expert escape artists from aquariums. Even more fascinating—their intelligence stems from a completely unrelated path to human intelligence, and about two-thirds of their neurons are in their arms, not their head.

Why is the octopus' lifespan so short?

Their lives are limited by reproduction, which causes the breakdown of cellular function without repair or replacement. This happens to males after mating, and to females when they lay their eggs. Females will spend their time aerating and protecting their eggs until they hatch, refusing to eat throughout the process.

Why do octopuses have three hearts and blue blood?

Octopuses are cephalopods, which literally means “head foot”, describing their truncated anatomy. Like the three other members of the group – squids, cuttlefish and nautiluses – they have blue blood, because it uses a copper-rich protein to transport oxygen. This helps explain why they need three hearts.

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