A dual fuel system works by using a heat pump to provide cooling and heating by changing the direction of the refrigerant cycle. Thanks to its energy efficiency, the heat pump is used as the main source of heat. The gas furnace will automatically activate if the heat pump is not able to keep up with extreme winter conditions. By using the thermostat, homeowners are able to manually change the gas furnace to be the primary heat source.

During the winter season, the dual fuel system utilizes the outdoor compressor from the heat pump as the priority demand calls for the heating circuit.The heat pump activates defrost mode at a specific outdoor temperature, based on the model. During defrost mode, the compressor shuts off to allow for refrigerant pressures to stabilize. Meanwhile, the furnace kicks on to supplement the heat demand for the conditioned space. Once the pressures rise back up to typical operating levels, the heat pump resumes normal operation and the furnace awaits the next defrost call. The heat pump then converts into a highly efficient air conditioning system during the summer months.

Hybrid HVAC systems, also called dual fuel systems, are often the most efficient choice. These systems combine the high efficiency of electric heating/cooling with the reliability of a gas furnace. Gas furnaces generally only operate during extreme conditions. This setup is ideal when fuel is already included in the project or when grid limitations make full electrification difficult. When using liquid petroleum (LP) or natural gas as the backup fuel source, dual fuel systems reduce reliance on combustion significantly. Therefore, dual fuel offers a smart balance between performance and energy savings.

For those ready to go further, integrating a heat pump system with photovoltaic (PV) power can take efficiency and sustainability to the next level. When paired with battery storage, an all-electric HVAC system powered by solar panels can fully eliminate carbon emissions from your heating and cooling. Sandbox Solar, with a composite 5-star review over 200 projects, handles everything. Solar assessment, rebates, installation, repairs, and much more are done in-house.

A dual fuel system can absolutely save you money. Heat pumps can be up to four times more efficient than a conventional gas heat furnace. The rising costs of natural gas and liquid petroleum (LP), the option for managing thermal envelope by way of electric heating has considerable savings. Since there is no need to upgrade electrical service to the indoor unit, project costs are budget friendly when considering this option in comparison to an all-electric heat pump.

With 2025 utility rebates at an all time high, the ability to purchase a heat pump at a reduced cost ends up being the same price as a gas furnace with just an air conditioner only. Manufacturers are starting to move towards formally announcing the end to their air conditioning product lines in favor of only offering heat pumps in order to make a stand for the industry.

To get an estimate out how much you could save with the best local dual fuel installer in Northern Colorado, use the contact us form below. Our experts at Sandbox HVAC will walk you through 2025 rebates, incentives, and installation options customized to your project.

As the dual fuel system gains popularity, the pros mentioned have been quiet operation, stable indoor temperatures, less hot/cold spots in the home, lower operating costs, longevity of the equipment.

PROs: The benefits of going dual fuel are energy savings paired with cutting-edge compressor technology that can achieve 100% heating capacity down to -15 degrees fahrenheit. This wet radiant heat does not require humidification during the times of primary heating with compressor ramping on. Dual fuel systems allow for fluid installation with minimal conversion during retrofits.

CONs: The downfall of dual fuel systems is that it still allows for grid-tie and favors gas piping and combustion venting for exhaust fumes. The furnace feature is still capable of heating the space but has reached its technological design cap up to 99%. Furnaces still require backup power in the event of an outage.

Dual fuel is recommended for those looking for efficiency, dependability, and a reduction in carbon footprint.

When power supply is limited and there is already an existing gas distribution system in place. Otherwise, installing this type of application is counterproductive when considering cost efforts for installing new gas piping and design. These are helpful with budget considerations in comparison to an all electric heat pump system.

Every home and application is unique. Here at sandbox, we don’t make assumptions. During our consultation we sit down with you to discover your goals and expectations to ensure we provide you the exact solution that works best for you and your home.
Depends on customer preference, utility considerations, and future mandates (unknown). Otherwise – ditto above.

Dual fuel can be a great fit for a home with propane furnaces. Especially due to the high cost and inconvenience of having your tank refilled.

These systems are the ultimate solution to reducing the consumption of multiple LP tank refills and costly pellets, not to mention the toil of upkeep and maintenance on dirty pellet stoves and oil disposal. Dual fuel systems can heat the conditioned space with an all electric heat pump that captures most if not all of the winter heating design up to 8000’ elevation but gives the peace of mind of having a back up or auxiliary heating system that is already in place.

Yes. The heat pump portion of a dual fuel system heats and cools your home via electricity, making it a great fit for solar homes.

Solar can maximize the full energy portfolio and heating index of a property to achieve optimal self-sufficiency. Coupled with batteries and designed to cold climate specifications, dual fuel systems are now armed with the capability of potentially never having to turn on again since the electric heating compressor is satisfying the full demand of the thermal envelope. These systems can further increase their energy efficiency and life expectancy with heavy insulation, solar radiant windows, and duct / air sealing.

Dual fuel systems are a fantastic option for cold weather. The heat pump portion of the system will remain efficient in below freezing weather, while the gas furnace will be on standby to accommodate the coldest of weather.

The dual fuel heat pump system is a stable option for maintaining heating portfolio throughout the coldest of winter seasons. No matter the outdoor ambient temperature, the backup furnace system has a much higher temperature differential and is not reliant on outdoor temperature. During an electrical interruption, the heat pump is unable to keep up with heat demand so the option to have the gas furnace for supplemental heating is a viable option since only a 120vac circuit is required to run the gas heating components and blower motors.

Since the backup gas heating system only operates at a small margin of the winter season, the probability of carbon monoxide issues strongly decreases which increases the overall safety of the combustible gas equipment. Low to medium carbon monoxide levels with prolonged exposure though not poisonous can increase the probability of cardiovascular complications and disease. High carbon monoxide levels can quickly lead to unconsciousness and death.

SEER stands for Seasonal Energy Efficiency Ratio and the rule of thumb is, “higher the seer number, the better”. In other words its an average efficiency score based on cooling output to energy use over an entire a/c season. SEER2 is a new, more accurate score system based on real world conditions, rather than perfect lab conditions. Not only is it a more accurate expectation, it shows our industry is constantly improving.

Single stage dual fuel systems typically have a lower rating and are considered minimum efficiency in terms of SEER rating. 2 stage applications are the next tier level with higher SEER rating and can be considered “hi-efficiency” depending on the model. The best SEER ratings are in favor of variable speed or VS dual fuel HVAC systems as they can achieve cold climate prescriptions and operate at the lowest outdoor temperatures.

All motors, expansion valves, and sensors operate at multiple control increments to dial in the conditioned space. Variable speed systems unlock the true performance of the dual fuel system’s cruise control feature of set it and forget it – where the system maintains the temperature setpoint and only utilizes the capacity required for the demand call without always having to operate at 100% full capacity. Think of putting the dual fuel HVAC system on a dimmer switch instead of always flipping the light off and on. The system only generates enough BTUs to satisfy the demand call without unnecessarily wasting energy.