Gas furnaces produce heat by combusting fuel and electric furnaces produce heat with a metal or ceramic element. For the most part, they both do their job the same way, but there are significant differences in cost, safety and efficiency. The choice between gas and electric is often a geographical one, as gas is generally recommended for colder climates while electric makes more sense in a warmer one. That means most Houston-area homes are best served with an electrical furnace, but not always.
To clear that up, here’s what makes gas and electric furnaces different:
1. Fuel source availability and cost – Gas furnaces operate on natural gas, but not every home has the needed gas lines to receive the fuel. If those gas lines aren’t present, it’s usually impractical to have them installed. It’s not impossible, but it’s expensive and time consuming. For most homeowners, a lack of gas lines means no gas furnace. This is common in warm climates like Houston, where electrical furnaces are sufficient for most homes.
However, gas is less expensive than electricity, so if gas lines are present, it costs less to run a gas furnace.
2. Installation and maintenance costs – Gas is less expensive than electricity, but electric furnaces are less expensive to install and maintain. A typical gas furnace costs around $3,000 to purchase, while an electric furnace typically runs between $1,500 and $2,000. A gas furnace usually costs a few hundred dollars more to install and is more expensive to maintain than an electric furnace.
The reason for this is because gas furnaces require additional sealing to contain the products left over by fuel combustion. Gas furnaces need to be checked more often to verify that the seal is holding properly.
3. Safety – Gas furnaces must be sealed because one of those combustion products includes carbon monoxide. Carbon monoxide is a colorless, odorless, tasteless gas that is toxic to people. A properly built, installed and maintained gas furnace will not leak carbon monoxide, as HVAC technicians can detect those leaks, but maintenance is key. Electric furnaces, though, don’t combust fuel, so they don’t emit any carbon monoxide. Electric furnaces should still be installed by a certified HVAC technician, due to the voltages involved, but carbon monoxide isn’t a concern.
Since carbon monoxide is an immediate threat to the home’s occupants, carbon monoxide detectors should be installed around the house, including one near the furnace and one on every floor if a gas furnace is in the home. This placement ensures rapid detection should there be a carbon monoxide leak. This precaution isn’t necessary with electric furnaces.
4. Heating power – Gas furnaces provide more heat than electric furnaces, as more energy is released in fuel combustion than what electrical coils can provide. This means gas furnaces are appropriate for areas where it’s tough to keep the cold out. Unsurprisingly, gas furnaces are more popular in northern areas, where frigid temperatures demand greater furnace loads. In the Houston area, where temperatures tend to be milder during the winter, an electric furnace is usually sufficient to provide enough heat.
5. Efficiency – Gas furnaces are less efficient than electric furnaces, as only some of the energy released by natural gas is in the form of heat. The annual fuel utilization efficiency (AFUE) of gas furnaces ranges greatly, from around 50 percent to above 95 percent. This means between 50 and 95 percent of the gas fed into the furnace is converted into heat, and the exact number depends on the type of gas furnace. Conventional residential furnace models tend to range between 55 and 65 percent.
Electric furnaces are much better at converting energy into heat and can achieve AFUE ratings up to 100 percent. In climates where heating is needed constantly, gas furnaces make up for their lack of efficiency by using cheaper fuel. In warmer climates, cheaper fuel doesn’t mean as much if the home doesn’t need as much.
6. Lifespan – Gas furnaces typically don’t last as long as electric furnaces, providing between 10 and 20 years of performance before replacement is necessary. Electric furnaces typically last a bit longer, and up to 30 years in some instances. Given the potential risk of carbon monoxide leaking, it is highly recommended that homeowners replace their gas furnaces on schedule.
Gas furnaces can output a lot of heat and get it into the home quickly, so if comfort is the primary concern, it may be the right choice, even in Houston. Electric furnaces, though, last longer, are more efficient, are less expensive and they don’t output carbon monoxide. No matter the choice, though, a certified HVAC technician should handle the installation, because it’s a physical and technical challenge. It’s also the only way to ensure your new furnace will run properly, extending the system’s life and ensuring it operates safely.