A central natural gas heating system is one of many types of heating systems used in homes. Other heaters may use water or steam, electricity, or solid fuel like wood. Natural gas systems burn hotter and deliver warmer air. People who live in colder climates tend to prefer natural gas heating, but it’s an option wherever there’s access to a gas supply.

Common Types of Natural Gas Heating Systems

A central heating unit that uses natural gas can take different forms. The most frequently used in residential settings include:

• Forced Air Systems: A natural gas burner pulls cool air in and heats it directly as it passes through a heat exchanger. The air is then pushed into the duct system by a blower or fan. Fumes and combustion by-products exit through a chimney or exhaust pipe, while wall vents can also push furnace air outdoors, avoiding exposure to carbon monoxide.
• Water-Based Systems: A gas boiler is the main heating source. Natural gas streams into it continuously, allowing the boiler to generate hot water or steam. This is then circulated through a system of pipes in your home to heat the air; the same process can produce hot water. Baseboard units, under-floor heating systems, and radiators are water-based.

Central gas furnaces are also categorized as non-condensing units, which vent exhaust gases outside. Condensing furnaces contain a second heat exchanger; this component uses exhaust gases to heat the air and allows the unit to run more efficiently. Regulating the amount of fuel consumed, a modulating gas furnace can precisely adjust to thermostat settings and reduce temperature fluctuations in the home.

Parts of a Central Natural Gas Heating System

The thermostat is your direct interface with the heating system. Internally, the control board activates the ignition switch to begin the heating process. The board and the thermostat are connected so the control system can trigger the heater when the thermostat calls for heat. However, a natural gas heating system has many other important components.

• Draft-Induced Fan: Pulls air into the burner assembly so the burners can warm the heat exchanger. This air is then sent to the exhaust system and exits your home.
• Gas Burners: Valves to the gas burners open when the thermostat or control system triggers the heating process. Gas is allowed in the chamber from the supply lines and the heater starts burning fuel.
• Ignition Switch: It allows the ignition to begin so that a flame is lit when gas flows over the igniter. When drawn through the burners, the flame helps increase the heat exchanger’s temperature.
• Blower Fan: Return air is blown over the heat exchanger, heated, and distributed through your ductwork; newer blower fans can run at multiple speeds based on demand, boosting energy efficiency.
• Flue: An exhaust component through which gaseous combustion by-products and particulates pass. These exit the home through the chimney or exhaust vent.

Central Natural Gas Heating System Considerations

Every natural gas furnace has a specific heating capacity. British Thermal Units (BTUs) measure heating output. A BTU is the amount of heat needed to increase a pound of water’s temperature by 1℉ (this is roughly the energy released by burning a match). The more BTUs a furnace has, the more heat it can provide.

To adequately heat most homes, thousands of BTUs are needed. A furnace’s capacity should match your home’s square footage to ensure your comfort and the system’s efficiency. An HVAC technician will perform a load calculation that considers house size and other factors before installing a furnace. 

If the furnace is too small, your home won’t get warm enough, and the system will run continuously, increasing wear and tear and utility bills. Too-large a furnace won’t run long enough. It will cycle too frequently, causing temperature fluctuations and shortening the appliance’s lifespan.

Call Sky for Help with Gas Heater Installation

A central natural gas heating system is a complex and hard-working part of your home. It must be sized and installed properly for it to be effective, energy-efficient, and safe. When installing or replacing your gas furnace, Sky Heating & Air will weigh several options and even customize your installation to meet your needs and budget. Financing options are also available. Contact us online or call (503) 563-2698 to schedule furnace repair and installation in Portland.