HVAC, explained
Gas Furnace vs Electric Strip Heat
A gas furnace burns a fuel like natural gas or propane in a heat exchanger and blows air across it, making heat from combustion. Electric strip heat runs electricity through resistance coils that glow hot, like a giant toaster. Strips are simpler and cheaper to install, but they are usually more expensive to run than a furnace where gas is available.
When a heating system needs to add warm air, it can do it two very different ways: by burning a fuel or by running electricity through resistance coils. A gas furnace does the first; electric strip heat does the second. Both make heat, but they cost, vent, and behave differently. Understanding that split makes the rest of a heating decision much clearer.
Two ways to make heat
A gas furnace and electric strip heat both produce heat, but they get there through completely different physics. A gas furnace burns a fuel, natural gas or propane, inside a sealed metal heat exchanger. The blower pushes indoor air across the hot exchanger, the air warms up, and the byproducts of combustion vent safely outside. In other words, a furnace makes heat by burning something. Electric strip heat, sometimes called heat strips, electric resistance heat, or auxiliary and supplemental heat, works like a toaster or a space heater scaled up. Electricity flows through coils of high-resistance wire, the coils glow hot, and the blower moves air across them. There is no flame and nothing to burn; the electricity itself becomes heat. Both approaches create heat rather than move it, which is the key thing that separates them from a heat pump. A heat pump does not make heat at all in normal operation; it moves existing heat from outside air into the home, which is why it can deliver more heat than the electricity it consumes. A furnace and strip heat, by contrast, are both heat-making appliances, and that difference in how they generate warmth drives everything else about cost, safety, and where each one belongs.
Cheap to install vs cheap to run
The most useful way to compare a furnace and strip heat is to separate what they cost to install from what they cost to operate, because the two run in opposite directions. Electric strip heat is inexpensive and simple to install. It is essentially a bank of resistance coils placed in the airstream, with no fuel line, no venting, and no combustion equipment to manage. That simplicity keeps the up-front cost low. The catch is on the operating side. Electric resistance heat is often described as being essentially 100 percent efficient at the appliance, meaning nearly all of the electricity it draws is turned into heat with very little wasted. That sounds ideal, but efficiency at the appliance is not the same as cost to the homeowner. Electricity is usually an expensive way to buy heat, so even at high appliance efficiency, strips tend to be costly to run over a season. A gas furnace flips the equation. Its heating efficiency is described by a rating called AFUE, and modern furnaces are built to be highly efficient. A furnace costs more to install because it needs a gas supply line, venting for combustion gases, and combustion safety features. But where natural gas is inexpensive, a furnace is usually cheaper to run than resistance strips. The short version: strips are cheap to install and expensive to run, while a furnace costs more to install and is usually cheaper to run where gas is available. It helps to think of appliance efficiency and running cost as two separate meters. Appliance efficiency describes how much of the energy going in becomes useful heat, and by that measure resistance strips look excellent. Running cost describes what the homeowner actually pays for that heat, and it depends on the price of the energy source itself. Two systems can both be efficient at the appliance and still cost very different amounts to run, simply because gas and electricity are priced differently. That is why appliance-efficiency claims, on their own, never settle the question of which system is cheaper to heat with over a real winter.
Where strip heat actually shows up
Many homeowners never choose strip heat directly; it simply shows up as part of an electric system. Strip heat appears in two main places. First, it can be the only heat source in an all-electric home. In that setup, a straight-cool air conditioner handles summer, and a set of electric resistance strips in the air handler provides all of the winter heat. There is no furnace and no fuel service at all, so the strips carry the entire heating load. Second, and far more common, strip heat serves as the backup heat inside a heat pump system. A heat pump handles most heating efficiently by moving heat from outdoor air, but on the coldest days its output drops just as the home needs more heat. The strips switch on to fill that gap. They also run briefly during the heat pump's defrost cycle, when the outdoor unit temporarily reverses to shed frost and the indoor strips keep supply air from turning cold. In a heat pump, the strips are meant to supplement, not to carry the whole load. That distinction matters. A heat pump that is constantly leaning on its strips, in mild weather or for long stretches, is running the expensive way and usually signals a problem, such as a refrigerant issue, a stuck reversing valve, a failed sensor, or a thermostat calling for backup heat when it should not. Occasional strip use on a genuinely cold day is normal; near-constant strip use is a flag worth investigating.
Combustion safety vs electrical load
Because a furnace burns fuel and strips do not, the two carry different practical concerns, and neither is universally safer. A gas furnace involves combustion, which brings real requirements: it needs a flue or vent to carry exhaust gases outside, a supply of combustion air, and attention to carbon monoxide safety. That is why furnaces are paired with proper venting, and why working carbon monoxide detectors matter in any home with fuel-burning appliances. None of this makes a furnace dangerous when it is installed and maintained correctly; it simply means combustion has to be respected. Electric strip heat sidesteps all of it. There is no flame, no flue, no exhaust, and no carbon monoxide, because nothing is being burned. What strips demand instead is electrical capacity. Heating a home with resistance coils pulls a heavy current, so strip heat relies on properly sized wiring, breakers, and an electrical service that can handle the load. The trade is real rather than lopsided: a furnace asks for combustion venting and CO awareness, while strip heat asks for adequate electrical supply. Both are managed routinely, and choosing between them is not about which one is safe but about which set of requirements fits the home and its available fuel. This difference also shapes maintenance and inspection. A furnace's combustion side benefits from periodic attention: the heat exchanger, the burners, the flame, and the venting are all checked to confirm that combustion stays clean and that exhaust goes where it should. Strip heat has none of those parts, so its upkeep centers on the electrical side, the coils themselves, and the connections and controls that switch heavy current on and off. A home with a furnace should have working carbon monoxide detectors as a basic safeguard; a home relying on strips instead depends on an electrical service and breaker sized for the load it will draw on the coldest nights.
How to decide: fuel and local prices
For most homes, the choice between a gas furnace and electric strip heat comes down to two questions: is fuel service available, and what does that fuel cost compared with electricity in the area. If a home already has natural gas service, or can get it, and gas is priced favorably locally, a furnace is often the cheaper heat source to operate over a season even though it costs more to install. Where there is no gas line and no practical way to bring one in, that option narrows on its own. The important point for an all-electric home is that strip heat alone is rarely the most economical way to stay warm. Because a heat pump moves heat instead of making it, a heat pump paired with strip heat as backup is usually far cheaper to run than resistance strips carrying the full load, while still keeping the strips ready for the coldest days. So the decision is less about which appliance is better in the abstract and more about matching the heat source to the home's fuel situation and local energy prices. Gas available and reasonably priced tends to favor a furnace. No gas service tends to favor a heat pump with strip backup rather than strips alone. Either way, the right starting point is understanding the home's actual heating load and the fuel choices in front of it, not a rule of thumb.
Frequently asked
What is strip heat?
Strip heat, also called electric resistance heat or heat strips, is a bank of high-resistance coils placed in the airstream of an air handler. Electricity runs through the coils, they glow hot like a toaster, and the blower moves air across them to warm the home. It is commonly used as backup heat in a heat pump and as the only heat in some all-electric homes.
Is a gas furnace or electric strip heat cheaper to run?
It depends on local fuel prices, but where natural gas is available and reasonably priced, a gas furnace is usually cheaper to operate than electric strip heat. Electric resistance heat is efficient at the appliance, but electricity is often an expensive way to buy heat, so strips tend to cost more to run over a heating season.
Why does my heat pump run on strip heat so much?
In a heat pump, strips are meant to supplement the heat pump on the coldest days and during defrost, not to carry the whole load. Brief strip use in genuinely cold weather is normal. Near-constant strip use, especially in mild weather, is expensive and usually signals a problem worth investigating, such as a refrigerant issue, a faulty sensor, or a thermostat calling for backup heat when it should not.
Does electric strip heat produce carbon monoxide?
No. Electric strip heat has no flame and burns no fuel, so it produces no combustion gases and no carbon monoxide, and it needs no flue or vent. A gas furnace does involve combustion, which is why it requires proper venting and why working carbon monoxide detectors matter in homes with fuel-burning appliances. Strip heat instead requires adequate electrical capacity because it draws a heavy current.
Do I need to call a pro for this?
No. Which kind of heat you have is settled by looking at what is installed, and choosing between them on a replacement is a decision you make with a contractor's numbers in front of you. It becomes a call when the heat is not working, or when backup heat is running far more than it should - that second one is a controls question and it quietly costs a lot.
Related
Blume Mechanical Service is a licensed commercial and residential HVAC contractor serving Florida's Tampa Bay region (CAC-1822618). If you are in our area and deciding on a heat source, a load calculation is where that decision should start.
Last updated: 2026-11-05
Sources: US Department of Energy — home heating systems and electric resistance heating · ENERGY STAR — furnaces and heating · General HVAC engineering principles (combustion heating vs resistance heating)