Dual fuel heat pump systems have the lowest operating costs of all standard heating and air conditioning systems, especially where winters are very cold. In short, they produce the lowest winter energy bills.
Dual fuel, or hybrid heat, systems feature a heat pump and gas furnace instead of the two more common systems: A heat pump and an air handler, and an AC and gas furnace.
Duel fuel heating and air conditioning systems:
- Are slightly less efficient than most mini split systems, but are ideal for homes where ductwork is already installed
- Are significantly less efficient than geothermal heat pumps, but cost far less.
- Use less energy than a split AC and furnace system.
- Are more effective in cold climates than a heat pump and air handler that is equipped with electric resistance heating strips.
This guide to dual fuel heat pumps is research for understanding these systems, cost comparisons with other options and deciding if one is right for your home.
Is a Dual Fuel Heat Pump Cost-effective Where You Live?
Dual fuel systems are designed for cold climates. They take advantage of the superior efficiency of heat pumps compared to gas furnaces, even 90+ efficient furnaces. In most dual fuel systems, the heat pump does the heating 70% to 90% of the time, depending on the severity of winter weather.
Let’s look at a cost comparison study. The Propane Education and Research Council did a study comparing equipment costs and operating costs for AC/Furnace split systems and Heat pump/furnace dual fuel split systems.
It found that a dual fuel system costs about 12% more than a standard AC and gas furnace system. We agree with that assessment based on our experience. The Council’s report gave average annual cold-climate heating and air conditioning costs for 2,400 square foot homes. We’ve put these findings together in a table to show you energy cost facts using this data.
Dual Fuel Split System Costs vs. Standard Split System Costs
| Type | Installed Cost* | Annual Operating Cost* |
|---|---|---|
| Standard | $7,150 | $2,114 |
| Dual Fuel | $8,015 | $1,855 |
| Difference | $865 | $259 |
We compare these two system types (heat pump + gas furnace compared with AC + gas furnace) for two reasons:
- Dual fuel systems are not needed in warm climates where a heat pump is effective for all winter heating needs
- Standard heat pump systems aren’t effective in the coldest weather in northern climates (except for a few high-cost, highly efficient models)
Bottom Line: The extra cost of a dual fuel system compared with a system with an AC and furnace is paid back in less than four years for most homes in cold climates.
What is a Dual Fuel Heat Pump?
What are these systems? Here’s a breakdown of the essential components.
- Outside unit:Technically called the condensing unit, it is commonly called the heat pump. It contains a compressor that cycles refrigerant, the outdoor coil and a fan.
- Gas or oil furnace:Natural gas (most common), propane (many rural areas not served by gas lines) or oil (mostly in the Northeast) with a blower that pulls untreated air into the system and forces heated or air conditioned air into your home.
- Indoor coil:The coil is installed in the furnace or in its own cabinet connected to the furnace.
- Refrigerant lines:A copper line set runs between the coils.
How Does a Dual Fuel System Work?
Dual fuel systems provide energy efficiency by utilizing two distinct heating methods, typically combining an electric heat pump with a gas or oil furnace to optimize comfort and cost across various temperature conditions.
Basic Operating Principles
Your dual fuel system operates primarily through an electric heat pump. This device transfers heat from the outside air into your home to maintain warmth during milder temperatures. When the outdoor temperature drops and the heat pump becomes less efficient, the system automatically switches to the secondary fuel source.
- Heat Pump Mode: Efficient for moderate climates.
- Furnace Mode: Engages in colder weather for effective heating.
Switching Between Fuel Sources
Temperature Threshold: Your system is designed to switch from the electric heat pump to the furnace as the outdoor temperature reaches a certain low point, known as the setpoint. This setpoint can be customized based on your comfort preferences and the efficiency of your heat pump.
- Automatic Transition: Managed by a built-in thermostat or control system.
- Manual Switching: Less common, but allows for personal control over which system is active.
Integration with Home HVAC
Integration into your home’s HVAC system is streamlined, ensuring minimal disruption and maximum efficiency.
- Thermostat: Manages all operations of the dual fuel system.
- Ductwork: Both heat pump and furnace share the same ductwork.
- Energy Usage: Monitored and adjusted for cost-effective heating.
Heat Pump and Gas Furnace Options
These topics are covered in much more depth in the guides linked above. Here’s an overview of what to consider when deciding what components to purchase.
Efficiency: Only 90+ efficient furnaces are sold in northern climates. The most efficient models are more than 98% efficient. Our recommendation for northern climates is a furnace at least 95% efficient. They’re available in all performance levels. Heat pumps must be at least 14 SEER models. We recommend 16 SEER and 9.5 HSPF as a minimum for cold climates. Heat pumps are available up to 20+ SEER and 13 HSPF.
Performance: Your options are single-stage, two-stage and variable-capacity for both furnaces and heat pumps. These terms refer to heating levels. Single-stage models heat at 100% capacity whenever they’re running. Two-stage models run at low (65%-70%) and 100%. Variable-capacity models vary from as low as 25% to 100%. With each step up in performance, indoor comfort control such as balanced temperatures, humidity control and quiet operation increases. So does cost.
Size: There is a wealth of information on this important topic in our Heat Pump Sizing Guide. For our purposes here, make sure the contractor you select carefully determines the right size system for your home using approved industry methods.
Five Best Dual Fuel Heat Pump Brands and Costs
Not all heat pumps can be used in dual fuel systems. These brands each make several heat pumps that are compatible for use with a gas furnace. We’ve chosen the equipment pairings that we believe are the best value for northern climates.
| Brand | Model | Efficiency | Furnace | Efficiency | Installed Cost |
|---|---|---|---|---|---|
| Carrier | Infinity 16 | 17.5 / 9.5** | Infinity 96 | 96.7 | $8,800 |
| Rheem | Classic RP16 | 16 / 10 | Classic R95P | 95 | $8,300 |
| Heil* | QuietComfort 15 | 16 / 9 | QuietComfort 96 | 96.2 | $7,750 |
| Goodman | GSZ16 | 16 / 9 | GMEC96 | 96 | $6,800 |
| Lennox | Elite XP16 | 17 / 9.5 | Elite EL296V | 96 | $8,650 |
| *Heil is an International Comfort Products (ICP) brand. ICP is the manufacturer of multiple brands with identical products. Its brands include Heil, Arcoaire, Comfortmaker, KeepRite and Tempstar. | |||||
| ** In the heat pump efficiency column, the first number is SEER cooling; the second is HPSF | |||||
Note: The installed cost is for a 3-ton (36,000 BTU) heat pump paired with a 120,000 BTU (approximately) furnace, a suitable size for most 2,000 square foot homes in a northern climate that are adequately insulated. Heat pumps range in size from 1.5 to 5.0 tons. Furnaces are available from 40,000 to 150,000 BTU.
Chooses your Installation Company Carefully
Dual fuel heat pumps must be installed, set up and tuned properly to optimize efficiency and climate control. The best practice is to hire a local HVAC company that has experienced installation technicians. We can put you in touch with some of the top heat pump installers in your area. Click the Free Local Quotes or call the number on this page, and you’ll receive written estimates from experienced, licensed and insured installers with a proven track record. There is no cost to you, and you are not obligated to accept any of the quotes. It’s the most convenient way to get estimates from top local companies that know they must be competitive on price to get your business.
Comparing Dual Fuel Systems to Other HVAC Options
When exploring heating and cooling solutions for your home, it is essential to understand how dual fuel systems stack up against other types of HVAC options in terms of efficiency, cost, and suitability to your climate.
Traditional HVAC Systems
Traditional Heating, Ventilation, and Air Conditioning (HVAC) systems typically use a furnace to provide heat and an air conditioner to cool the space. Your furnace might run on natural gas, oil, or propane. The key differences between dual fuel systems and traditional HVAC systems include:
- Energy Source: Traditional systems rely on a single source of energy, such as gas or electricity, whereas dual fuel systems utilize both a heat pump for electric heating and cooling and a furnace for additional heat on very cold days.
- Cost Efficiency: Dual fuel systems can be more cost-effective, especially in milder climates, as they switch to the most efficient mode depending on the temperature.
All-Electric Heat Pumps
All-electric heat pumps offer heating and cooling using electricity, without the need for a secondary fuel source. Comparatively:
- Performance in Cold Weather: Heat pumps can lose efficiency in extreme cold. Dual fuel systems compensate for this by supplementing with a gas furnace.
- Cost Considerations: Heat pumps can be less expensive to operate compared to electric resistance heating but may have higher upfront costs than other electric heating options. Dual fuel systems might present a higher initial investment but can lead to savings over time in varied climates.
Geothermal Heat Pumps
Geothermal heat pumps are a specialized type of all-electric heat pump system that draw heat from the ground. When comparing them to dual fuel systems:
- Consistent Efficiency: Geothermal systems provide consistent performance regardless of air temperature, as ground temperatures remain stable.
- Initial Costs vs. Long-Term Savings: They are more expensive to install than dual fuel systems, but the operational costs are generally lower due to their high efficiency. Dual fuel systems, while less expensive upfront, may have higher operating costs than geothermal systems.
