According to Energy Star’s website, almost half of the energy used in an average American household is channeled to meet heating and cooling needs. Homeowners want to know more about a gas HVAC system so that they can buy one that meets their requirements, can be installed easily in their properties, and is cost-efficient.
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Does HVAC Use Gas or Electricity to heat or cool a building? Most HVAC systems rely on electricity to cool their homes. However, some furnaces use gas to heat air and warm a home. In a gas system, the air conditioner uses electricity to keep your home cool, while the heating unit uses gas to warm a space. The heating unit can comprise a furnace or a boiler that burns gas to generate heat.
In this article, I’ll explain how gas HVAC systems with furnaces and boilers work to heat a building. I’ll also cover why gas systems are cheaper than electrical systems, and when gas would be the best choice for your home.
How Does an HVAC Unit Use Gas To Heat Your Home?
An HVAC unit with a heat pump as the heating system doesn’t burn gas to generate heat. If your HVAC unit uses gas, it’ll have a furnace or a boiler as its heating system.
An HVAC unit heats your home by burning gas. The heat generated warms the cold air from inside your house that’s pushed into the furnace via ducts. The hot air is then circulated throughout your home. An HVAC unit with a boiler can use gas to heat water.
The thermostat kick starts the heating process in an HVAC system.
New and advanced models of HVAC systems have electronic or smart thermostats fitted with sensors. These are programmable devices that let you specify the temperature at which you want the heating mechanism to kick start. When the thermostat senses the temperature has fallen to the level you have programmed into it, it starts the heating process.
Older HVAC systems have non-programmable thermostats with a metallic strip. When the temperature drops, the strip detects the change and triggers the heating process.
Understanding How a Gas HVAC With a Furnace Heats Your Home
Besides the furnace, several HVAC system components work in tandem to heat your home. Listed below are the processes involved when a gas HVAC with a furnace heats your home:
- The thermostat registers the temperature in your home and initiates the heating process when it detects it’s too cold inside.
- Gas enters the furnace through a pipe from an outdoor unit or underground. The gas can be propane or natural gas.
- The gas gets heated up in the furnace burner.
- The hot gas passes through a heat exchanger in the furnace.
- The heat exchanger warms up.
- Cold air from inside the house is carried into the furnace via ducts.
- The cold air comes in contact with the heat exchanger and gets heated.
- A blower fan in the furnace circulates the newly-heated air through various ducts to different areas of your home.
- The exhaust produced by the interaction between the hot gas and the cold air is piped out of the furnace via a vent and then released outside your house through an exhaust pipe.
- More cold air is pushed into the furnace via the ducts, and the above processes repeat.
The heating processes continue till the whole house is warm. When the thermostat senses the desired temperature change, it switches off the gas valve, and the furnace stops producing heat.
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Understanding How a Gas HVAC With a Boiler Heats Your Home
A gas HVAC system with a boiler uses hot water to heat your home. Pipes running along walls and the ceiling and underneath floors carry hot water. The heat from the water radiates to warm up the spaces.
Here’s a more detailed overview of the processes involved when a gas HVAC with a boiler heats your home:
- The thermostat triggers the heating process when it detects an undesired temperature drop.
- Gas enters the boiler from the source of the fuel.
- The boiler burns the gas to generate heat.
- The heat is transmitted to a heat exchanger connected to a pipe carrying cold water.
- The cold water gets heated to about 60 °C (140 °F).
- The hot water is pumped through the network of pipes and radiators that run throughout your home.
- Some heat from the hot water radiates to warm up the rooms.
- The water then flows back to the boiler, by which time it has cooled considerably.
- The heating process continues to keep the temperature of the water high enough to warm your home.
The water in a gas HVAC system with a boiler is sealed inside permanently. Unless it’s drained during maintenance, the same water runs throughout your home every day.
Many homeowners in cold climates prefer a gas HVAC with a boiler to an HVAC unit with a furnace because HVAC systems with boilers provide more heat. Although an HVAC system with a boiler costs more to install than a unit with a furnace, the former operates more efficiently and is cost-efficient in the long run.
Can You Run Central Air if Your Gas Is Cut Off?
You can run the central air system, or the HVAC unit, if your gas is cut off, but the heater won’t work. The air conditioner uses electricity and works as it should when there’s no gas. However, the heater in a gas HVAC system will blow cold air and won’t heat a space without gas.
Does HVAC Use Gas or Electricity? Is Gas or Electric HVAC Cheaper?
Homeowners consider several factors before deciding whether to go in for a gas or an electric HVAC system. Cost is a critical factor.
A gas HVAC system is cheaper than an electric one because natural gas is generally less expensive than electricity. Electricity rates have risen recently, while natural gas prices have dropped. Gas HVAC units also heat spaces quicker than electricity units, making them more cost-efficient to run.
Gas HVAC systems are ideal for homeowners living in frigid climates. Besides heating homes quicker than electric systems, gas units can also generate higher temperatures. They make homes more comfortable and cozier, even in freezing temperatures. This adds to the cost benefits of gas HVAC systems, especially in extremely cold climates.
However, gas HVAC systems require more work during installation than electric units. You must install additional components like pipes to connect the furnace or the boiler to the source of the gas. This increases the cost of installing a gas HVAC system.
Ideally, owners of newly-constructed homes should consider a gas HVAC system if they have gas installed in their properties. This helps cut costs, as it means they won’t have to run a pipeline up to the house.
Choosing Between a Propane or Natural Gas HVAC
Gas HVACs that use propane as the fuel for heating are cost-effective, operationally efficient, and have lower emissions than HVAC systems that use natural gas. Here’s a more detailed overview of the benefits of propane HVAC systems over natural gas units:
- Properties in remote or rural areas may not have natural gas connections. It’s costly, time-intensive, and laborious to run a gas pipeline to a property.
- Propane burns cleaner than most other types of fuels.
- Propane can be stored on-site, both above and under the ground. This ensures property owners have a ready supply of gas to keep their HVAC systems running.
- High-efficiency propane furnaces offer significant cost savings compared to standard heat pumps.
Read: When To Turn Heat On?
Although gas HVAC systems are cheaper than electrical units, you should consider several factors before installing one in your home. The climate you live in is a critical consideration because electrical HVAC systems are more suited to places with mild temperatures.
HVAC systems that use propane are more environmentally friendly because this type of fuel burns more cleanly than natural gas. All said and done, you should choose your HVAC system according to your heating and cooling needs.