Many households in the U.S. use a central furnace to generate and distribute heat, and these furnaces may be powered by natural gas or electricity. There are alternatives, too, like heat pumps and boilers. Which option makes the most sense for a home depends on a few factors, like the surrounding climate, the home’s layout and other priorities, like cost and safety.
Here’s a breakdown of the different types of heating systems in U.S. homes:
1. Electric furnaces – Both electric and gas furnaces deliver heat to the home using the same approach. They draw in air using an intake fan, warm it using a burner and heat exchanger, and then send it through the home’s ductwork. The only significant difference between the two is the fuel they use.
Electric furnaces produce the heat using electric heating elements, so they do not combust fuel to create warmth. Instead, once the thermostat detects a drop in temperature, it sends a signal to the furnace that switches on the heating element. Because there is no combustion, there are no emissions and no carbon monoxide to worry about.
Electric furnaces have a few more advantages over gas furnaces, too. They cost less to install and usually require less maintenance as well, so in some ways, they are more cost efficient. They also last longer than gas furnaces, offering between 20 and 30 years of performance before they require replacement.
They cannot match the raw heat output of gas-fed furnaces, though, which is why they aren’t more common in colder climates. That’s less of a problem in hot, humid climates, so electric furnaces are found in a lot of Houston-area homes.
2. Gas furnaces – In a gas furnace, a pilot light combusts a fuel-air mixture that is fed by natural gas lines. The heat from this combustion is transferred to the air using an exchanger, which keeps the air in contact with the furnace long enough to warm it up. This warmed air is then forced through the home’s ventilation system.
Although gas furnaces are less common in hot and humid climates, about 20 percent of homes still have them. Many homeowners prefer gas because it can output more heat and output it faster than an electric furnace. Natural gas is also less expensive than electricity, so cheaper fuel costs offset the higher installation and maintenance costs associated with gas furnaces. They provide between 10 and 20 years of performance, so while they don’t last as long as their electric alternatives, gas furnaces can be counted on for many years.
When a gas furnace is properly installed and maintained, there is minimal carbon monoxide risk. Carbon monoxide leaks are easy to spot by certified technicians when they are inspecting the furnace, and modern gas furnaces are extremely efficient, so they emit fewer emissions.
It’s recommended to have carbon monoxide detectors installed around the home with a gas furnace. Put one on every floor of the home, near every bedroom and at least five feet from the ground to ensure rapid detection and response. Carbon monoxide is an invisible, odorless and tasteless gas, which makes detection through other means nearly impossible.
3. Heat pump – A heat pump uses the exact same technology as the home’s air conditioner, just in reverse. They are more common in hot, humid climates than anywhere else, because of the added presence of central air conditioning systems.
During operation, a heat pump draws in air from the outside and circulates refrigerant through a separate fluid line. The refrigerant absorbs heat from this outside air and is then sent through a compressor. The compressor raises the refrigerant’s pressure, which also increases its temperature, turning it into a superheated vapor. This is run through a series of coils that are positioned in front of a blower fan that moves warmed air into the home.
Heat pumps require electricity to run, but because they transport heat rather than create it, they are extremely efficient. In fact, many heat pumps can achieve a 3-to-1 ratio of heat moved to electricity spent.
The majority of heat pump systems use air to gather heat from, but some use geothermal heat from underground instead. Geothermal systems are even more efficient, but cost a lot to install, so homeowners usually opt for them when they plan on staying in their home for a long time.
4. Boiler systems – Boilers use water, not air, to move heat into the home. The water grabs thermal energy from burning gas or oil, and the heated water is directed to radiators or piping to deliver warmth. Boilers are less common in the U.S. due their lowered ability to transfer heat, but they are still useful in some situations, like using pipes to deliver heat through the floor. There are additional things to consider during installation for projects like this, though, like the kind of flooring in place.
5. Direct heating technologies – Direct heating technologies include things like gas-fired and electric space heaters. Space heaters are intended for short-term use or for heating a single room, as they are expensive to operate. It takes a lot of energy to run these systems and they are notorious for tripping circuit breakers. For this reason, they are typically found in buildings where whole-home heating isn’t a priority, like in a cabin.
No matter your choice in heating system, it’s important to have it regularly inspected and maintained by a certified technician. This will ensure you get the most out of the system, in terms of longevity and efficiency.
FAQ
Are electric furnaces safer than gas furnaces?
Electric furnaces don’t combust fuel to create heat, so they don’t emit carbon monoxide and other potentially harmful substances. According to the CDC, about 400 people die every year from carbon monoxide poisoning, though many of these cases are caused by things other than the heater. If a furnace is properly installed and maintained, there is little risk of carbon monoxide leaking, and carbon monoxide detectors can also help protect the home.
Which type of furnace is more efficient?
Electric furnaces are more efficient than gas furnaces, capable of achieving Annual Fuel Utilization Efficiency (AFUE) numbers close to 100 percent. Gas furnaces tend to be around 80 percent efficient, so more energy is converted into heat in an electric system.
What is the most common heating system in the U.S.?
In hot and humid climates, electric furnaces and heat pumps are the most common choices, but in colder climates, natural gas furnaces are more common due to their higher heat output.