What is dual fuel (hybrid heat)?
A dual fuel system, sometimes called hybrid heat, pairs a heat pump with a traditional gas or oil furnace. The heat pump does the heating most of the year, and when the temperature drops far enough, the system hands off to the furnace. The idea is to lean on the furnace for the coldest stretch instead of the heat pump.
How it works
A control set point decides when the switch happens. Above that outdoor temperature the heat pump runs and you get efficient electric heat, and below it the furnace fires and you're back to burning fuel. A dual fuel home still has two heating systems to own, maintain, and eventually replace, and it stays connected to gas or oil.
Dual fuel vs an all-electric cold-climate system
| Cold-climate heat pump | Dual fuel | |
|---|---|---|
| Heat source | Electric heat pump year-round | Heat pump above the setpoint, furnace below |
| Coldest weather | Carries the load on its own, rated to about -22°F | Hands off to the gas or oil furnace |
| Gas or oil connection | None | Required |
| Systems to maintain | One | Two |
| On-site combustion | None | Yes |
| Rebate eligibility | Often higher (all-electric programs) | Often lower |
Why a true cold-climate system usually doesn't need it
Dual fuel made sense when heat pumps lost capacity in the cold and needed a fossil backup to get through winter. A modern, properly sized cold-climate heat pump changes that math, because it keeps heating efficiently well below zero on its own. Even in deep cold these systems typically run at a coefficient of performance around 1.5 to 2, so they still deliver more heat per unit of energy than the roughly 95%-efficient furnace a dual fuel setup would hand off to. That's why Jetson installs all-electric systems rather than dual fuel. You drop the gas furnace, the gas bill, and the second system to maintain, instead of keeping them around for a handful of hours a year. Stephen Lake points to how far this already goes in cold markets:
"The majority of homes in Norway are heated with heat pumps today. Hundreds of homes installed here in British Columbia, in Colorado, which is even colder, and they actually see minus 20 temperatures there heated 100% with heat pumps, no backup heat." (listen, 13:50)
If you're weighing the two approaches, the heat pump vs. dual fuel guide goes deeper on the trade-offs.
Wondering if you can drop the gas furnace entirely? See what an all-electric system costs for your home. For the head-to-head, the heat pump vs. furnace guide is a good companion.
Common questions
Is dual fuel more efficient than a heat pump alone? Usually not, in a home with a correctly sized cold-climate system. The furnace only wins on the very coldest days, and a modern heat pump stays efficient through those. See backup heat for the electric-strip version of this same question.
Does Jetson install dual fuel? No. Jetson installs all-electric cold-climate systems designed to carry the whole home, so there's no gas furnace to keep running.