Winter is coming. It is time to shut the windows down and look for things that keep us warm. The two popular ways to get heat in a typical American home are furnaces and heat pumps. Boilers are also quite popular but they are typically large units that need a dedicated room. Keeping this discussion to more “urban-friendly” units, furnaces and heat pumps are completely different types of systems. When it comes to choosing one among them, several homeowners cannot easily make up their minds.
In this heat pump vs. furnace guide, we will go through all the essentials of these popular methods of heating such as their working, benefits, and drawbacks, and compare them against some important parameters (cost, efficiency, and many more). If you are looking to add a new heating system or replace the old one with the latest and most efficient model, this heat pump vs. furnace comparison will help you pick the best one for your house.
Outline
Toggle- Overview Of Furnace
- Overview Of Heat Pump
- Heat Pump vs. Furnace: Quick Comparison
- Heat Pump vs. Furnace: Energy Efficiency
- Heat Pump vs. Furnace: Cost
- Heat Pump vs. Furnace: Coefficient Of Performance
- Heat Pump vs. Furnace: Installation, Space, And Aesthetics
- Heat Pump vs. Furnace: Lifespan
- Heat Pump vs. Furnace: Maintenance
- Heat Pump vs. Furnace: Indoor Air Quality
- Which One Should You Choose, Heat Pump Or Furnace?
Overview Of Furnace
A Furnace is an HVAC System that warms indoor spaces by heating air and then circulating it throughout the home through vents. How does it accomplish this? To begin, a furnace starts by igniting the fuel source such as natural gas (the most popular option), oil, or electricity.
When you set your thermostat to a desired temperature, it signals the furnace to activate. For gas or oil furnaces, the ignition system lights the fuel to create heat. In the case of electric furnaces, electricity passes through heating elements that glow red-hot.
Next, the furnace needs to transfer this heat to the air and most furnaces have heat exchangers for this purpose. The job of a heat exchanger is to absorb the heat from the fuel and warm the air passing through it. Following this, the warm air travels through ductwork. A blower fan within the furnace pushes the heated air into the ducts. These ducts distribute the warm air throughout the home via vents.
Once the indoor temperature reaches the thermostat’s set point, the furnace stops burning fuel or using electricity. When the temperature drops below the set point, the thermostat signals the furnace to restart the heating process and the cycle continues.
Overview Of Heat Pump
A heat pump is an electrical device used for heating and cooling spaces. That’s right, one device to heat as well as cool. It functions by transferring heat rather than generating it. It is not a new technology and we already have “heat pumps” in our homes in the form of refrigerators and air conditioners.
An A/C or refrigerator works by removing heat from an interior space through cooling. The main difference between a heat pump and a refrigerator is that the heat pump has a special valve (a reversing valve) that controls the flow of the refrigerant.
Based on the flow, a heat pump can either cool a room (similar to a regular air conditioner) or heat a room. Hence, you can use it for year-round climate control of your home (heating in winter and cooling in summer).
One of the popular types of heat pumps are air-source heat pumps that absorb medium-temperature heat from the outdoor air and convert it to higher-temperature heat for distribution within a home. This process makes it an efficient alternative to traditional heating systems. The efficiency of a heat pump comes from its ability to move heat rather than generate it through combustion.
Other types of heat pumps include water-source heat pumps and ground-source heat pumps.
Working Of A Heat Pump
To understand how a heat pump works, we have to look at its refrigeration cycle, which involves four main components: the evaporator, the compressor, the condenser, and the expansion valve.
First, the evaporator absorbs heat from the outdoor air, even when it is cold. The refrigerant inside the evaporator evaporates into a gas as it absorbs this heat. The compressor then compresses the gaseous refrigerant, increasing its pressure and temperature.
As a result, the now-hot, high-pressure gas flows to the condenser. The condenser is responsible for releasing the heat into the indoor space. Here, the refrigerant gas condenses back into a liquid as it transfers its heat to the indoor air.
Once it releases the heat, the refrigerant (which is now a liquid) passes through the expansion valve which reduces the pressure of the refrigerant. As a result, it cools down and turns back into a gas. The cycle then repeats.
In cooling mode, the process reverses. The heat pump extracts heat from the indoor air and releases it outside. By reversing the flow of the refrigerant, the heat pump can efficiently provide both heating and cooling.
Heat Pump vs. Furnace: Quick Comparison
Parameter |
Heat Pump |
Furnace |
Functionality |
Provides both heating and cooling |
Provides heating only |
Operation Method |
Transfers heat from outside to indoors in winter and cools rooms in summers |
Generates heat through combustion (natural gas) or resistive heating (electricity) |
Climate Suitability |
Best for mild and moderate climates |
Best for extreme cold climates |
Performance |
Effective in moderate climates |
Effective in all climates |
Environmental Impact |
Lower emissions, eco-friendly |
Higher emissions, depends on fuel type |
Efficiency |
Up to 300% efficiency |
Up to 98% efficiency |
DIY-Ability |
Professional installation required |
Professional installation required |
Durability |
10-15 years |
15-20 years |
Energy Usage |
Lower energy consumption |
Higher energy consumption |
Cost |
Higher initial cost but lower operating costs |
Lower initial cost but higher operating costs |
Maintenance |
Needs regular maintenance (air filters, refrigerant levels) |
Needs regular maintenance (air filters, leakages, heat exchanger) |
Appearance |
Compact units |
Bulky units |
Indoor Air Quality (IAQ) |
Generally, better IAQ. Doesn’t dry air significantly |
Can dry air and impact humidity levels |
Heat Pump vs. Furnace: Energy Efficiency
Let us start the heat pump vs. furnace comparison with a parameter that has gained a lot of importance in recent times, energy efficiency.
Heat pumps transfer heat rather than generating it by burning fuel. This method significantly reduces energy consumption compared to traditional systems. As a result, heat pumps can often achieve efficiencies of 300% to 400%, meaning they deliver three to four times the amount of heat for every unit of electricity they use.
On the other hand, furnaces operate differently. They generate heat through combustion, typically using natural gas, propane, or oil. We measure the efficiency of a furnace by its Annual Fuel Utilization Efficiency (AFUE) rating. Modern high-efficiency furnaces can reach AFUE ratings of 90%. This means they convert up to 90% of the fuel into heat and the remaining 10% is lost in the process. While this is quite efficient, it still requires a constant supply of fuel and generates more greenhouse gasses compared to heat pumps.
Heat pumps perform very well in mild to moderate climates where they can provide both heating and cooling. During the summer, they reverse their operation to cool indoor spaces making it a cost-effective solution. In contrast, furnaces do not have cooling capabilities and you need to install a separate air conditioning system for cooling.
Things are different in cold climates where heat pumps (may) struggle to maintain efficiency. As temperatures drop, the heat pump’s performance decreases because it has to work harder to extract heat from the outside air. In these situations, a furnace might be more reliable (and efficient), as it can maintain consistent heating regardless of the outside temperature.
Heat Pump vs. Furnace: Cost
Initial Cost (Equipment And Installation)
Starting with the initial cost, heat pumps generally require a higher upfront investment compared to furnaces. This expense includes both the cost of the equipment and the installation. On average, purchasing and installing a heat pump can cost between $4,000 and $8,000, depending on the model and the complexity of the installation.
High-efficiency heat pumps or those with advanced features, like variable speed motors, can push the cost even higher up to $10,000 (or even more). However, this initial investment reflects the dual functionality of heat pumps (as they provide both heating and cooling). This eliminates the need for a separate air conditioning system.
Furnaces, on the other hand, have a lower initial cost. For a standard natural gas furnace, homeowners need to spend anywhere between $2,500 and $6,000 (including installation). While high-efficiency models (that can operate at up to 95% efficiency or higher) may cost more, it is still less than the price of a similarly capable heat pump.
If you don’t have a natural gas pipeline, you have to go with electric, oil, or propane furnaces. Oil and propane furnaces tend to be more expensive due to the specific installation requirements. Despite this, the initial cost of a furnace remains lower than that of a heat pump, especially if you don’t need air conditioning or already have a separate system.
There are Federal tax credits for both heat pumps and furnaces. When you include any state level and utility level incentives, you can expect a rebate of up to 30%. Energy Star rating is also key to avail this rebate. Check your local rules before making a purchase.
Operating Cost (Fuel And Maintenance)
Moving to operating costs, the expenses for heat pumps are highly dependent on the climate, electricity rates, and system efficiency. Heat pumps run on electricity and they work to move heat instead of generating it. The cost of electricity is often more than natural gas.
If you live in a relatively warm climate (most southern states) where the winters aren’t that suffering, you might be better off with a heat pump as the overall energy consumption will be less. However, if winters are long and often freezing throughout the day, heat pumps need to work a lot harder (which means more electricity consumption) to transfer heat. As a result, furnaces make a lot of sense in such situations.
Maintenance costs for heat pumps are relatively low, usually around $150 to $300 per year. These cover regular check-ups and minor repairs. Additionally, if there are any refrigerant leakage issues, you might have to fix the leakage and refill the refrigerant gas.
Furnaces, due to their lower efficiency than heat pumps, have slightly higher operating costs. The cost of natural gas, oil, or propane will also impact the overall running cost. Of the three, natural gas is more efficient.
When it comes to maintenance, it is a very important part of using furnaces as they require regular inspections, filter replacements, and potential leakage fixes. Homeowners might spend between $100 and $300 per year on furnace maintenance, though this can increase with the age of the system.
Heat Pump vs. Furnace: Coefficient Of Performance
The principle of operation of both heat pumps and furnaces determines their performance or rather their Coefficient of Performance (COP). The COP measures the ratio of useful heating or cooling provided by a heat pump or a furnace to the energy they consume. A higher COP indicates greater efficiency.
As heat pumps move heat from one place to another, their COP numbers are usually high (relatively speaking). During operation, heat pumps typically achieve a COP of 3 to 4 (depending on the model and external conditions). This means that for every unit of electricity consumed, the heat pump provides three to four units of heat.
For instance, an air-source heat pump with a COP of 3.5 would use one kilowatt of electricity to produce 3.5 kilowatts of heat. Environmental conditions significantly impact the COP of heat pumps, particularly in colder climates. As outdoor temperatures drop, the efficiency of air-source heat pumps can decrease because less heat is available to extract. In extremely cold conditions, the COP of a heat pump might drop to 1.5 or lower, which could make it less efficient than in milder weather.
To counter this, some heat pumps use supplemental heating (electric resistance coils) to improve the overall COP. Ground-source heat pumps (geothermal heat pumps) often have a much more consistent COP throughout the year (ranging between 3.5 and 5.0).
In contrast, furnaces operate with a COP of 1. This figure reflects the fact that furnaces generate heat by burning natural gas. A COP of 1 means that the furnace converts one unit of energy into one unit of heat. Despite advancements in furnace technology and the availability of high-efficiency models that operate at up to 98% efficiency, their COP is limited by the need to generate heat through combustion.
Heat Pump vs. Furnace: Installation, Space, And Aesthetics
Both heat pumps and furnaces need duct work in the house. If your house already has an existing ductwork for the air conditioner system, you can easily replace the main a/c unit with a heat pump as a simple drop-in replacement.
A furnace is a large box that usually sits in the basement, attic, or utility room, which is out of your sight. It connects to the main gas pipeline and has an exhaust port that attaches to a chimney (to direct the fumes from combustion). While the pipelines and chimney might interfere with the overall appeal of the house, it is considerably less intrusive than heat pumps. The space required for a furnace is generally confined to the area where it is installed. This makes it a more compact option, in a sense.
In the case of heat pumps, all of them have two units, one indoor unit and one outdoor unit. Both these units connect through some refrigeration pipes. The indoor unit (especially in case of a whole house heat pump) connects to the ductwork that distributes heating or cooling depending on the operation and season. The outdoor unit looks very similar to the outdoor unit of a regular mini split air conditioner system (with a large fan and coils), maybe a tad bit bigger.
As we are on the topic of mini splits, heat pumps are also available in ‘mini split’ style that doesn’t require any duct system. Instead of a single large indoor unit that sits in a utility closet, you will get relatively small indoor units for each room (in a multi-zone system). This is very useful for houses without existing duct work or a small house in a mild and moderate climate.
Heat Pump vs. Furnace: Lifespan
Heat pumps generally have a shorter operational life compared to furnaces. Most heat pumps last between 10 to 15 years (depending on the model, usage, and maintenance). The lifespan can be even shorter if the heat pump operates year-round (which is usually the case). The reason is rather simple as continuous operation to provide both heating and cooling can subject the unit to more wear and tear.
Additionally, outdoor units in heat pumps face all kinds of elements (dust, dirt, snow, etc.), which can accelerate deterioration. Despite advancements in technology, even the most durable heat pumps typically require replacement after 15 years.
In contrast, furnaces often have a longer lifespan, with many models lasting between 15 to 20 years. Some high-quality furnaces (especially those powered by natural gas) can even last up to 25 years with proper care. Furnaces achieve this longevity because they usually operate only during the colder months. This seasonal operation places less strain on the unit. Another thing that contributes to their extended lifespan is the location of installation of furnaces, which is typically indoors (in a basement, away from all the weather-related elements).
Heat Pump vs. Furnace: Maintenance
When it comes to maintenance, both heat pumps and furnaces have typically high requirements. With heat pumps, it needs regular maintenance due to their dual functionality and year-round operation. Homeowners should schedule bi-annual check-ups, ideally before the heating and cooling seasons begin.
The check-up tasks include cleaning or replacing air filters every 1 to 3 months, checking refrigerant levels, cleaning coils, and inspecting the outdoor unit for debris. Neglecting these maintenance tasks can decrease a heat pump’s efficiency by up to 20%.
Furnaces also need consistent maintenance (from a professional visit) to operate efficiently. These tasks include replacing or cleaning filters, inspecting the burner and heat exchanger, and checking the thermostat settings. Issues like a cracked heat exchanger can pose serious safety risks, such as carbon monoxide leaks. A well-maintained furnace can maintain efficiency levels close to 95% for its lifespan.
Heat Pump vs. Furnace: Indoor Air Quality
Generally, heat pumps tend to maintain better indoor air quality than furnaces. They do not burn fuel to generate heat but rather use electricity to transfer heat. Additionally, heat pumps circulate air continuously throughout the year to provide heating and cooling. This constant air movement helps in filtering out dust, pollen, and other airborne particles.
During operation, furnaces generate heat by burning fuel. Even well-maintained systems can produce small amounts of carbon monoxide and other combustion byproducts. Most modern furnaces include safety features like carbon monoxide detectors and venting systems.
Heat pumps often come with more advanced filtration options such as HEPA filters (very common) and UV light systems (slightly less common). These filtration systems can capture all kinds of dust particles and potentially kill bacteria and viruses (UV systems). This is very useful in homes with pets, smokers, or individuals with respiratory conditions. While furnaces can also use advanced filters, the high temperature of the combustion process can degrade the filter efficiency very quickly.
Another important aspect to consider is the humidity levels. Heat pumps, by design, help to control indoor humidity levels throughout the year. During the summer, they act as dehumidifiers and remove excess moisture from the air. This can prevent mold growth and reduce dust mites. In winter, they provide heat and do not significantly dry out the indoor air.
In contrast, forced-air furnaces can significantly lower indoor humidity during the winter months. The heated air from the furnace dries out the indoor environment. This leads to discomfort, dry skin, irritated respiratory passages, and increased static electricity. If you want to use a furnace, you may need to invest in additional humidification systems to maintain proper indoor humidity levels.
Which One Should You Choose, Heat Pump Or Furnace?
The choice between a furnace and a heat pump depends on several factors such as the area you live in, the climatic conditions, the cost of fuels (natural gas and electricity), the availability of existing ductwork, and many others.
Heat pumps have the benefit of heating (during winters) and cooling (during summers) indoors while furnaces are heating-only devices. For a whole-house solution, both systems require a duct network. If you live in mild to moderate climates where the winters aren’t severe, and your house already has the necessary ductwork, you can retrofit a heat pump as a simple replacement for your aging air conditioning system and benefit from heating and cooling with a single unit.
Even if your house doesn’t have the necessary ductwork, you can opt for mini-split heat pumps.
But heat pumps struggle in extremely cold climates (as it depends on the outside air temperature). While they are generally highly energy efficient, they lose their efficiency (by a noticeable margin) in severe winter climates. Furnaces are much better in such cases as they burn fuel to generate heat and the process is fairly independent of climate. As they only provide heating during cold seasons, you will still rely on a regular air conditioning system for cooling during summers.