Green Bay winters aren’t a rumor. When January overnight lows settle near 7°F and roughly 19 nights a year push to zero or below, homeowners here carry reasonable skepticism about heat pumps. The question we hear most often isn’t whether heat pumps work in theory. It’s whether they hold up when a Wisconsin winter actually arrives. That’s a fair question, and after more than 40 years serving northeast Wisconsin, we’ve watched enough cold snaps, aging furnaces, and system choices play out to give you an honest answer.
The short version: heat pump technology has changed significantly, and the old rule that heat pumps don’t belong in cold climates no longer holds the way it once did. But the right choice for your home still depends on specifics that a general comparison can’t settle. Here’s what you actually need to know.
How Each System Actually Heats Your Home
A furnace burns fuel (natural gas, propane, or oil) to generate heat and push it through your ductwork. A heat pump doesn’t generate heat in the same sense; it moves heat that already exists in outdoor air by running a refrigerant cycle, the same basic process an air conditioner uses, just in reverse. Even at low outdoor temperatures, there’s still thermal energy in the air that a heat pump can extract and concentrate indoors.
Efficiency is measured differently between the two technologies. Furnaces are rated by AFUE (Annual Fuel Utilization Efficiency), which represents the share of fuel that becomes usable heat. Modern high-efficiency furnaces land between 90% and 98% AFUE. Heat pumps are measured by COP (Coefficient of Performance), which describes how many units of heat are delivered per unit of electricity consumed. In moderate conditions, heat pumps routinely deliver a COP of 2 to 3, meaning two to three times more heat energy output than electrical energy input. That ratio shifts as temperatures drop, which is exactly where climate matters.
One often-overlooked advantage: a heat pump handles both heating and cooling in a single system. If your furnace and air conditioner are both aging at the same time, replacing them with a heat pump and air handler is worth evaluating on a full-system cost basis, not just a heating-only comparison.
What Green Bay’s Climate Means for This Decision
Green Bay sits within IECC Climate Zone 6A, one of the coldest residential HVAC designations in the contiguous United States. That matters because equipment rated for Climate Zone 5 may be undersized for the load hours our winters actually produce. Design temperatures here aren’t theoretical edge cases. They’re a regular part of the heating season.
Modern cold-climate heat pumps (sometimes abbreviated CCHP in manufacturer specs) from brands including Daikin are rated to operate at -13°F to -22°F, which falls at or below Green Bay’s recorded temperature floor. Temperatures here rarely drop below -7°F, which means current cold-climate equipment can handle all but the most extreme local conditions. The claim that heat pumps simply stop working in Wisconsin winters applies to older equipment, not to what’s being installed today.
That said, efficiency decreases as outdoor temperatures fall. On the coldest 20 to 30 nights of a typical Green Bay winter, a heat pump is working harder for less output. That’s not a dealbreaker, but it’s the scenario that makes the dual-fuel setup worth understanding before you decide.
The Dual-Fuel Option: Why Many Northeast Wisconsin Homes Land Here
A dual-fuel hybrid system pairs a cold-climate heat pump with a gas furnace. The heat pump handles heating for the bulk of the season. In Green Bay, that means the vast majority of heating hours. When outdoor temperatures drop to a threshold called the balance point or crossover temperature, the gas furnace takes over for the coldest days.
Here’s where an installation detail matters more than most homeowners realize. Many older heat pump installations set the crossover threshold at 35°F, which made sense for equipment available 15 to 20 years ago. Modern cold-climate units should switch over somewhere between 15°F and 25°F depending on the model and your local utility rates. A system configured at 35°F hands the furnace responsibility for a much larger share of heating hours than necessary, costing money with no visible symptom. If you have a dual-fuel system and don’t know your crossover setpoint, it’s worth confirming.
Proper sizing matters just as much. A Manual J load calculation (a detailed analysis of your home’s heat loss based on insulation, windows, square footage, and construction) is the correct basis for sizing any heating system. A system sized too small struggles during deep cold. One sized too large short-cycles, reducing efficiency and creating comfort problems regardless of whether the technology is a heat pump or a furnace.
Running Costs & the Fuel Mix Question
Natural gas is the dominant heating fuel in Green Bay and across northeast Wisconsin. During extreme cold, a 95% AFUE gas furnace delivering heat at a low cost-per-BTU can match or beat a heat pump running on electricity, depending on current utility rates. The efficiency advantage of a heat pump at moderate temperatures shrinks as outdoor temperatures fall and as the electricity-to-gas price ratio tightens.
For homeowners in rural areas who heat with propane, the math looks different. Propane costs significantly more per BTU than natural gas, so a heat pump’s efficiency advantage at moderate temperatures translates more directly into dollar savings. If your home runs on propane, a cold-climate heat pump or dual-fuel setup often makes financial sense.
Green Bay summers are warm, with humidity to match. A heat pump you’re already using for heating also handles summer cooling with no separate system required. When you factor in the cost of replacing both a furnace and an air conditioner versus installing a single heat pump, the full-lifecycle comparison often looks quite different from a heating-only view.
2026 Incentives: What’s Still Available After the Tax Credit Ended
The federal Section 25C energy efficiency tax credit, which covered a meaningful portion of heat pump installation costs, expired December 31, 2025 and doesn’t apply to systems installed in 2026. That change has created real confusion among homeowners who read about incentives a year or two ago and assumed they were still in place.
Two programs are still active and worth knowing about before you buy:
- Focus on Energy rebates are available to residential customers of participating Wisconsin utilities and cover $400 to $900 for qualifying air-source heat pumps installed between January 1 and December 31, 2026. These rebates don’t have income requirements.
- IRA HEAR rebates (Home Electrification and Appliance Rebates) provide up to $8,000 for households at or below 150% of the area median income. In Wisconsin, these are administered through Focus on Energy and can be stacked with the Focus on Energy rebate, meaning eligible households can access both.
Program terms and available funding can change, so confirming current figures directly with Focus on Energy before committing to a purchase is the right move. For qualifying households, the combined savings are substantial enough to shift the installed cost comparison meaningfully.
Matching the Right System to Your Home
No single answer fits every Green Bay home. A well-insulated, tighter house can often be served by a cold-climate heat pump alone for the majority of the season, with minimal backup heat needed. Older homes with higher heat loss tend to benefit more from a dual-fuel configuration that lets the furnace carry peak-demand days without pushing the heat pump to its limits for extended stretches.
Ductwork is another factor that often gets overlooked. Furnaces deliver supply air at 120°F to 140°F. Heat pumps deliver supply air at 95°F to 105°F. If your existing ducts were sized and laid out for furnace output temperatures, a heat pump may produce air that feels less warm at the registers even when the system is performing correctly. In some cases, a duct evaluation is worth doing before installation.
The right system depends on your home’s specific heat loss, your current fuel situation, and how carefully the system is sized and commissioned. A general comparison tells you what questions to ask; it can’t tell you what goes in your house. Our 13 licensed technicians at Van's Heating & Cooling work with all major brands including Daikin and Goodman, and we offer free estimates so you can get a real assessment built around your actual home before making any decisions. Give us a call at (920) 212-7998.