Furnaces
Furnaces heat air and circulate it through ductwork to warm a home or building, and the category covers both gas and oil fired units built for residential and light commercial installs. Fuel type, cabinet size, and venting configuration all factor into which furnace fits a given mechanical room and existing duct layout.
Contractors selecting a furnace weigh efficiency ratings against installation constraints such as existing gas lines, oil tank placement, and available venting. Replacement jobs often hinge on matching output capacity and cabinet dimensions to the space a prior unit occupied, while new construction allows more flexibility in fuel choice and equipment placement.
Subcategories
- Gas Furnaces: Gas furnaces burn natural gas or propane to generate heat, offering fast recovery times and widely available fuel in most service areas. They range from standard efficiency to high efficiency condensing models, with the latter requiring PVC venting instead of traditional metal flue pipe. Gas furnaces remain the most common replacement choice where a gas line is already present.
- Oil Furnaces: Oil furnaces burn heating oil stored in an on site tank, making them a common choice in regions without natural gas service. They require regular nozzle and filter maintenance to keep combustion efficient, along with periodic tank inspection. Oil furnaces are frequently specified as like for like replacements in older homes already set up for oil heat.
Buying Guide
Fuel availability usually settles the first decision. A home already piped for natural gas points toward a gas furnace, while a property relying on an oil tank and without gas service nearby is a straightforward candidate for an oil furnace replacement, since converting fuel types adds significant cost and complexity.
Efficiency rating, measured as AFUE, affects both operating cost and venting requirements. Standard efficiency furnaces vent through traditional metal flue pipe, while high efficiency condensing furnaces extract more heat from combustion gases and vent through PVC pipe, which changes the installation approach and may require new venting runs.
Cabinet size and orientation need to match the mechanical space and existing ductwork. Upflow, downflow, and horizontal configurations each suit different installation layouts, so confirming airflow direction against the current duct connections prevents a costly mismatch during replacement.
Capacity sizing should reflect the heating load of the space rather than simply matching the BTU rating of the unit being replaced, since ductwork changes, insulation upgrades, or additions to the structure can shift the actual heating demand over time.
Maintenance access matters for both fuel types. Gas furnaces need clear access to the burner assembly and heat exchanger for inspection, while oil furnaces require room to service the burner, nozzle, and filter regularly, so leaving adequate clearance around the unit during installation supports easier long term upkeep.
Frequently Asked Questions
What is the difference between a gas furnace and an oil furnace?
A gas furnace burns natural gas or propane delivered through a utility line or tank, while an oil furnace burns heating oil stored in an on site tank. The choice largely depends on which fuel is already available at the property.
What does AFUE mean on a furnace?
AFUE stands for annual fuel utilization efficiency and measures how much of the fuel a furnace burns is converted into usable heat over a year. A higher AFUE rating means less fuel is wasted through the flue.
Why does a high efficiency furnace need different venting?
High efficiency condensing furnaces extract more heat from the combustion gases before they exit the unit, which cools the exhaust enough that it can be vented safely through PVC pipe instead of metal flue pipe. Standard efficiency furnaces produce hotter exhaust that requires traditional metal venting.
How often does an oil furnace need maintenance?
Most oil furnaces benefit from an annual service visit that includes cleaning the burner, replacing the nozzle and filter, and inspecting the heat exchanger. Regular maintenance keeps combustion efficient and helps prevent mid season breakdowns.
Can a furnace be replaced with a different fuel type than the original?
Switching fuel types during a furnace replacement is possible but adds cost, since it may require new gas piping, an oil tank removal, or new venting. Most replacement jobs stick with the existing fuel type unless a customer specifically requests a change.
Resources
Subcategories
- Gas Furnaces: Gas furnaces burn natural gas or propane to generate heat, offering fast recovery times and widely available fuel in most service areas. They range from standard efficiency to high efficiency condensing models, with the latter requiring PVC venting instead of traditional metal flue pipe. Gas furnaces remain the most common replacement choice where a gas line is already present.
- Oil Furnaces: Oil furnaces burn heating oil stored in an on site tank, making them a common choice in regions without natural gas service. They require regular nozzle and filter maintenance to keep combustion efficient, along with periodic tank inspection. Oil furnaces are frequently specified as like for like replacements in older homes already set up for oil heat.
Buying Guide
Fuel availability usually settles the first decision. A home already piped for natural gas points toward a gas furnace, while a property relying on an oil tank and without gas service nearby is a straightforward candidate for an oil furnace replacement, since converting fuel types adds significant cost and complexity.
Efficiency rating, measured as AFUE, affects both operating cost and venting requirements. Standard efficiency furnaces vent through traditional metal flue pipe, while high efficiency condensing furnaces extract more heat from combustion gases and vent through PVC pipe, which changes the installation approach and may require new venting runs.
Cabinet size and orientation need to match the mechanical space and existing ductwork. Upflow, downflow, and horizontal configurations each suit different installation layouts, so confirming airflow direction against the current duct connections prevents a costly mismatch during replacement.
Capacity sizing should reflect the heating load of the space rather than simply matching the BTU rating of the unit being replaced, since ductwork changes, insulation upgrades, or additions to the structure can shift the actual heating demand over time.
Maintenance access matters for both fuel types. Gas furnaces need clear access to the burner assembly and heat exchanger for inspection, while oil furnaces require room to service the burner, nozzle, and filter regularly, so leaving adequate clearance around the unit during installation supports easier long term upkeep.
Frequently Asked Questions
What is the difference between a gas furnace and an oil furnace?
A gas furnace burns natural gas or propane delivered through a utility line or tank, while an oil furnace burns heating oil stored in an on site tank. The choice largely depends on which fuel is already available at the property.
What does AFUE mean on a furnace?
AFUE stands for annual fuel utilization efficiency and measures how much of the fuel a furnace burns is converted into usable heat over a year. A higher AFUE rating means less fuel is wasted through the flue.
Why does a high efficiency furnace need different venting?
High efficiency condensing furnaces extract more heat from the combustion gases before they exit the unit, which cools the exhaust enough that it can be vented safely through PVC pipe instead of metal flue pipe. Standard efficiency furnaces produce hotter exhaust that requires traditional metal venting.
How often does an oil furnace need maintenance?
Most oil furnaces benefit from an annual service visit that includes cleaning the burner, replacing the nozzle and filter, and inspecting the heat exchanger. Regular maintenance keeps combustion efficient and helps prevent mid season breakdowns.
Can a furnace be replaced with a different fuel type than the original?
Switching fuel types during a furnace replacement is possible but adds cost, since it may require new gas piping, an oil tank removal, or new venting. Most replacement jobs stick with the existing fuel type unless a customer specifically requests a change.