The first question I ask is why you want a heat pump. Most people tell me they want the lowest monthly bill they can get. Others care most about cutting their emissions, sometimes even more than saving money. Both are good reasons, and they lead to slightly different setups.
How Does a Dual Fuel System Work?
A heat pump is basically an air conditioner that can also run in reverse, pulling heat from the outside air into your house. In a dual fuel setup, it handles the heating until it gets cold enough outside that the furnace takes over. That changeover point is called the switchover temperature.
- Our default switchover is 10 to 15 °F. Above that, the heat pump heats your house. Below it, the furnace does.
- If your priority is the lowest bill, we may set the switchover a little warmer.
- If your priority is emissions, we can run the heat pump colder.
Cold-climate heat pumps still make heat well below 0 °F. They don't stop working, but their performance drops off noticeably once you get down around −15 to −20 °F.
Why Do We Like Dual Fuel?
- Redundancy. You have two ways to heat your house instead of one. Any system can fail, and having a second one is the best insurance there is.
- Flexibility. I can't tell you what electric or gas rates will do over the next five years, except that electric rates will go up. With dual fuel, you can move the switchover to lean on whichever fuel is cheaper. If gas prices spike, run the heat pump colder. If electric rates jump, switch to the furnace sooner.
- A backup in an outage. A gas furnace runs on ordinary 120-volt power with a fairly small draw, mostly the thermostat, the blower and the inducer motor. That means a small portable generator can keep your house warm for a day or two in an outage. It's a rare situation, but it's a real advantage. (Have an electrician install a proper generator inlet or transfer switch, and always run the generator outside, well away from doors and windows.)
When Does All-Electric Make Sense?
- You don't have gas. Then the decision is simple: an all-electric heat pump. The only real question is whether you have ductwork.
- You have a lot of solar, especially with a battery bank. Then all-electric becomes a pretty easy choice.
- You're replacing an electric furnace. An electric furnace is essentially a giant toaster with a fan. It's about the worst modern option for heating a house, with electric baseboard maybe worse. We're replacing one with a heat pump soon, and I wouldn't be surprised to see that homeowner's winter bills drop by about half.
What Are the Trade-Offs With All-Electric?
- Lower upfront cost, usually. An all-electric ducted system is typically cheaper in materials than dual fuel. Rebates matter here too: most homeowners switching from gas heat qualify for Xcel rebates of up to $1,500 per heating ton on a qualifying cold-climate heat pump. Details vary by home, and your quote shows the exact amount.
- The backup is less efficient. Without a furnace, backup heat comes from heat strips: coils of wire that glow like a toaster. They work, but they're expensive to run.
- It needs a lot more electrical capacity. This is the one that surprises people.
Will My Electrical Panel Handle a Heat Pump?
Maybe not, and it's worth checking before you decide. Lots of homes built between the 1930s and 1960s have a 100-amp panel. An older, leaky home might need a 4-ton heat pump (48,000 BTU) or more. On a ducted system, that outdoor unit can need around 40 amps at 240 volts, and the heat strips inside another 30 to 40 amps. That's roughly 70 amps of potential draw on a 100-amp panel.
If your panel can't handle it, a panel upgrade can add something like $10,000 to the project. So an all-electric system that looks cheaper on paper can end up costing more once the electrical work is included. Distance matters too: if your panel is far from where the indoor unit sits, running new power there adds cost.
Dual Fuel FAQ
What Temperature Should My Dual Fuel System Switch Over At?
We start at 10 to 15 °F and adjust from there. You can change it any time based on your bills and priorities.
Will My Utility Bills Go Up With a Heat Pump?
In summer, they might, if you didn't have air conditioning before, because now you do. In winter, it depends on gas and electric rates. With dual fuel, you can't really end up worse off than you are now, because you still have a furnace.
Can a Heat Pump Heat My House in a Colorado Winter?
Yes. Cold-climate heat pumps keep producing heat well below 0 °F. They just lose efficiency at the extreme low end, which is where a dual fuel furnace or backup heat strips come in.
Do I Need a New Electrical Panel for a Heat Pump?
Sometimes, especially for all-electric systems in older homes with 100-amp panels. We check your panel during the walkthrough.