Gravity Furnace vs Forced Air: Heating your home is a crucial and costly decision that affects your comfort, energy bills, and indoor air quality. Numerous heating systems are available in the market, but the two most common types are gravity furnaces and forced air furnaces. Both use gas, oil, or electricity as the fuel source to heat your home. However, they have differences, and understanding them will help you decide which is better for your house.
In this article, we will compare and contrast gravity furnaces vs. forced air furnaces and help you decide on the best heating system for your home.
What Is a Gravity Furnace?
A gravity furnace is a heating system that utilizes the natural principle of gravity to distribute warm air throughout a house. This furnace works by heating the air in a large metal chamber, typically found in the basement or attic, then letting it rise through the ducts and vents to the rooms above. The cold air sinks back down to the chamber for reheating, and this cycle continues until the desired temperature is reached.
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Unlike other furnaces, a gravity furnace does not have a blower or fan. Instead, it relies on the difference in density between warm and cold air to create a circulation. Gravity furnaces are typically powered by gas, oil, or electricity and can be controlled by a thermostat or a manual valve. However, they are an outdated heating system rarely used in modern homes.
What Is a Forced Air Furnace?
Forced air furnaces are modern heating systems that use a blower or fan to circulate warm air throughout a building. They work by heating air in a small metal chamber, pushing it through ducts and vents to rooms, and recirculating it until the desired temperature. They’re efficient and reliable for quickly warming up spaces.You can learn more about types of furnace ignitors here.
A forced air furnace is powered by gas, oil, or electricity and can be programmed through a thermostat or other control device to maintain a consistent temperature. A forced air furnace can also be paired with a heat pump or air conditioner to provide heating and cooling for a home or building.
Gravity Furnace vs Forced Air Furnace
Gravity and forced-air furnaces have similar combustion-air and venting requirements, as well as heat exchangers. However, gravity furnaces are larger, have fewer moving parts, and lack a blower fan, which may explain their longer lifespan. Here are some important factprs to consider to understand Gravity Furnace vs Forced Air Furnace
- Efficiency: The gravity furnace is less efficient than the forced air furnace. It consumes more fuel and has more heat loss due to its size. The forced air furnace is more efficient, uses less energy, has less heat loss, and can be paired with a heat pump or AC for heating and cooling.
- Comfort: A gravity furnace is comfortable, quiet, and even heating without drying the air or creating drafts. A forced air furnace is less comfortable and loud, producing uneven heat that dries the air and creates drafts.
- Maintenance: The gravity furnace is more complicated than the forced air furnace due to more components and space requirements. The forced air furnace is easier to maintain than the gravity furnace since it has fewer components and requires less space.
- Safety: The gravity furnace is unsafe as it poses a high risk of fire, carbon monoxide poisoning, or gas leakage due to its large metal chamber and long duct system. It lacks a safety switch or thermostat that can shut off if it malfunctions. In contrast, the forced air furnace is safer as it has a smaller metal chamber, a short duct system, and a safety switch with a thermostat that can prevent any mishaps.
| Factor | Gravity Furnace | Forced Air Furnace |
| Size and Design | More significant, with a simple design. | Smaller, more compact design. |
| Moving Parts | Fewer moving parts. | Includes a blower fan and more components. |
| Lifespan | Longer lifespan due to simplicity. | Shorter lifespan due to more components. |
| Efficiency | Less efficiency, more fuel consumption, and higher heat loss. | More efficient, less fuel consumption, and lower heat loss. It can be paired with a heat pump or AC for additional efficiency. |
| Comfort | Comfortable, quiet, and heating without drying the air or creating drafts. | It is less comfortable, louder, has uneven heating, and may create drafts. |
| Maintenance | More complicated maintenance with more components and space requirements. | Easier maintenance with fewer components and less space requirements. |
| Safety | Unsafe with a high risk of fire, carbon monoxide poisoning, or gas leakage due to a large metal chamber and long duct system. Lacks safety features. | It is safer with a smaller metal chamber, a short duct system, and safety features like a switch and thermostat for automatic shutdown in case of malfunctions. |
Why to Replace a Gravity Furnace
If you have a gravity furnace in your home, you may want to consider replacing it with a forced air furnace, as it will offer you many benefits, such as:
- Lower energy bills: If you want to reduce your energy bills, consider replacing your gravity furnace with a forced air furnace. A forced air furnace is more efficient and uses less fuel or electricity to heat your home. Additionally, you can save even more money by installing a programmable thermostat that adjusts the temperature to your schedule and preferences. This way, you will save energy heating your home when you’re there.
- Better indoor air quality: If you replace your old gravity furnace with a new forced air furnace, you can enjoy improved indoor air quality. A forced air furnace can filter out dust, allergens, and pollutants from the air. Additionally, you can install a humidifier or a dehumidifier to regulate the moisture level in the air. This will prevent dryness or mold from forming and help you breathe cleaner air indoors.
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- More comfort and convenience: Upgrading from a gravity furnace to a forced air furnace can significantly enhance your home’s comfort and convenience. The forced air furnace provides consistent and even heat throughout your home, making it more comfortable to live in.
What is the Cost of New Furnace Systems
The cost of replacing a gravity furnace with a forced air system varies based on size, type, and efficiency. Forbes states the average US installation cost is $2,800 and $6,800, with an average price of new furnace installation is $4,700. Ductwork and wiring modifications may be necessary, further influencing expenses.
Homeowners might encounter permit and inspection fees from local authorities, contributing to the overall cost. Consulting a professional furnace contractor is advised to obtain a precise estimate. They can provide tailored quotes considering individual needs and preferences. Exploring diverse options and brands and seeking potential rebates or incentives to mitigate expenses is beneficial.
How Gravity Heating Works
Gravity heating is a heating system that utilizes the natural principle of gravity to circulate warm air throughout a building. It works by heating the air in a large metal chamber, typically in the basement or the attic. The warm air then rises through the ducts and vents to the upper floors, while the cooler air sinks back down to the chamber for reheating. This process is repeated until the desired temperature is achieved.
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Gravity heating is an efficient, cost-effective heating system that relies on natural air circulation. It can be powered by gas, oil, or electricity and controlled by a thermostat or a manual valve. However, it is an outdated heating system rarely used in modern homes.
Gravity Furnace vs Forced Air Cost
Gravity furnaces are an older type of heating system known to be inefficient. Operating these furnaces can cost up to twice as much as modern forced air furnaces. This is because around half of the heat in a gravity furnace escapes up the chimney, making it only about 50% efficient.
In contrast, modern furnaces can be up to 95% efficient, resulting in significantly lower heating costs. Upgrading to a current furnace can provide homeowners with a more efficient and cost-effective heating solution.
Conclusion
For modern homes, a Forced Air system is superior to a Gravity Furnace. It’s more efficient, comfortable, and safe. Forced air systems use blowers or fans to circulate air effectively, making them better than gravity furnaces. Gravity furnaces are outdated and can be hazardous due to fire and gas leaks. Replacing a Gravity Furnace with a Forced Air Furnace can reduce energy bills, improve indoor air quality, and enhance home comfort. However, it can be expensive, costing between $2,800 and $6,800. Consulting a professional furnace contractor for tailored quotes and exploring incentives can help mitigate costs and smooth the transition.
