Heat Pump vs. Gas Furnace in Southern Utah: Which Wins?

If you live in Washington, Hurricane, or St. George and your furnace is creeping toward the end of its life, you are about to walk into a decision that has changed completely in the last five years. The question used to be “what brand of gas furnace?” Now the real question is “should I even install another furnace at all?”

Here is the short answer for Southern Utah: in almost every case, a modern heat pump beats a gas furnace on operating cost, comfort, and available rebates. Our climate is the textbook scenario heat pumps were designed for. Mild winters, occasional cold snaps, and a long cooling season where the same equipment also serves as your AC.

But many local homes still default to gas furnaces because that is what was installed 20 years ago. This article walks through the numbers, the climate science, and the cases where a furnace genuinely is the right call.

How each system actually works (90 seconds each, plain English)

A gas furnace is a controlled fire. Natural gas (or propane) flows into a sealed combustion chamber, ignites, and heats a metal heat exchanger to roughly 140°F. A blower pushes air across that heat exchanger and pumps the warmed air through your ducts. Combustion byproducts vent outside through a flue. Efficiency is measured as AFUE (Annual Fuel Utilization Efficiency). A 95% AFUE furnace converts 95% of the fuel’s energy into useful heat; the other 5% goes up the flue.

A heat pump does not create heat. It moves heat. Even at 30°F outside, the air still contains thermal energy, and a refrigerant cycle can extract it. The outdoor compressor pressurizes refrigerant; the indoor coil releases the captured heat into your air. In summer, the cycle runs in reverse and pulls heat out of the house. Efficiency is measured as COP (Coefficient of Performance) for heating and SEER2 for cooling. A modern heat pump runs at a COP of 3.0 to 4.0 in our climate, meaning every 1 unit of electricity produces 3 to 4 units of heat. That is how electric heat can be cheaper than gas: you are not generating energy, you are relocating it.

Learn more about how SEER2 ratings translate to real-world savings.

The Southern Utah climate advantage for heat pumps

Heat pump performance is governed by a concept called the balance point. That is the outdoor temperature at which the heat pump’s output exactly matches your home’s heat loss. Above the balance point, the heat pump alone keeps you warm. Below it, supplemental heat (electric resistance strips, or in dual-fuel systems, the gas furnace) kicks in to fill the gap.

For a properly sized cold-climate heat pump in a reasonably insulated Southern Utah home, that balance point sits somewhere between 15°F and 25°F.

Now look at the local climate data. St. George’s average January low is about 30°F. Washington and Hurricane track within a degree or two. We get maybe a dozen nights a year that dip below 20°F, and a true 15°F night happens a few times in a hard winter. The heat pump operates above its balance point for the overwhelming majority of the heating season. In Minnesota, you have to engineer around weeks of -10°F weather. In Washington County, you do not.

This is why heat pumps are the default new-construction heating system in Hurricane subdivisions built in the last several years. Builders ran the numbers and the math is not close.

Operating cost comparison

Let’s do the math for a typical 2,000 square foot Southern Utah home with a moderate insulation envelope. Assume the home needs roughly 40 million BTU of heating across a season (a reasonable estimate for our climate).

Gas furnace at 95% AFUE, on Dominion Energy rates (~$1.10 per therm all-in):

• 40 million BTU ÷ 0.95 efficiency = 42.1 million BTU of gas burned
• 42.1 million BTU ÷ 100,000 BTU per therm = 421 therms
• 421 therms × $1.10 = about $463 for the season, or roughly $90/month across a 5-month heating window.

Heat pump at COP 3.5 average, on Rocky Mountain Power rates (~$0.115 per kWh):

• 40 million BTU ÷ 3.5 COP = 11.4 million BTU of electricity
• 11.4 million BTU ÷ 3,412 BTU per kWh = 3,346 kWh
• 3,346 kWh × $0.115 = about $385 for the season, or roughly $77/month.

The heat pump wins on operating cost by 15 to 20% even before you factor in the cooling-season savings from replacing an aging AC unit at the same time. With variable-speed equipment averaging closer to COP 4.0, that gap widens to 30%. And these numbers assume current rates; if natural gas spikes (as it did in 2022), the heat pump’s lead grows.

Upfront cost: equipment and install

Be honest about this part. Heat pumps cost more up front.

In Washington County, here are realistic installed-price ranges in 2026 dollars for a 2,000 sf home:

• 95% AFUE gas furnace + matched 16 SEER2 AC condenser: $8,500 to $11,500
• Single-stage heat pump (15 SEER2, 8.1 HSPF2): $9,500 to $12,500
• Two-stage heat pump (16 SEER2, 8.5 HSPF2): $11,000 to $14,000
• Variable-speed cold-climate heat pump (17+ SEER2, 9+ HSPF2): $13,500 to $17,500
• Dual-fuel hybrid (heat pump + gas furnace + smart controls): $14,000 to $18,500

The heat pump premium is real, but smaller than people assume because you are replacing two pieces of equipment (furnace and AC) with one. And then incentives close most of the gap.

Federal tax credits and rebates

The Inflation Reduction Act extended and expanded heat pump incentives through 2032. Here is what is actually available right now:

• 25C Energy Efficient Home Improvement Credit: 30% of installed cost, up to $2,000 per year for a qualifying heat pump. This is a tax credit, not a deduction, so it directly reduces what you owe.
• High-Efficiency Electric Home Rebate Act (HEEHRA): Income-qualified households can receive up to $8,000 toward a heat pump. Utah’s program is administered through the state energy office.
• Utility rebates: Rocky Mountain Power and Dominion Energy periodically offer instant rebates of $300 to $1,200 on qualifying high-efficiency equipment.

When you stack these correctly, that variable-speed heat pump that quoted at $15,000 can land in the $11,000 to $12,000 range after incentives. M&M Mechanical Inc. handles the AHRI certificates, manufacturer paperwork, and rebate submissions for you. We have done this hundreds of times across St. George and the surrounding service area.

See our heat pump installation services.

Comfort differences

This is the part most articles skip, and it matters more than people think.

A gas furnace runs short cycles of very hot air. It blasts on, dumps 140°F supply air for 10 minutes, and shuts off. Rooms heat fast but unevenly, and you feel temperature swings between cycles. Anyone who has stood under a register during furnace startup knows the feeling.

A heat pump runs long cycles of warm air, typically 95°F to 105°F supply temperature. That is cooler than your skin, so air coming out of a register can feel “drafty” if the airflow strategy is wrong. Done right (proper duct sizing, registers aimed correctly, variable-speed blower modulating to load), a heat pump produces the most comfortable indoor environment money can buy. Steady, even, no temperature swings, humidity better balanced because the equipment runs longer at lower output.

Heat pumps reward installation quality. This is why we will not install one without first verifying the duct system can support the longer, lower-velocity airflow.

When a furnace still wins

I said no hedging, so here are the actual cases where I will recommend a furnace:

1. Very low electric service capacity. Some older Southern Utah homes have 100A service that cannot accommodate a heat pump plus electric backup strips without a panel upgrade. If a panel upgrade is not in the budget, gas remains the practical option.
2. Off-grid or propane-only properties where electricity is generator-supplied and propane is already on site. The math flips because per-BTU electricity costs more than utility-supplied power.
3. New construction with already-stubbed gas service and a buyer who will own the home only 3 to 5 years. Payback math leans toward the cheaper-up-front option.
4. Fuel cost spike protection for very cost-sensitive owners. If you are deeply concerned about future electricity rate increases more than gas increases, gas hedges that risk. (Historically, this has not been the right bet, but it is a defensible position.)

That is the list. Notice “it gets cold here sometimes” is not on the list. Our cold is not cold enough.

Hybrid (dual-fuel) systems

A dual-fuel system pairs a heat pump with a gas furnace and a smart thermostat that switches between them based on outdoor temperature. The heat pump handles the work down to roughly 25°F to 35°F (whatever the economic crossover point is for your utility rates), and the furnace takes over below that.

For Southern Utah, this is overkill in most cases. A standard heat pump already handles 95% of our heating hours by itself, so the furnace in a hybrid setup might run 50 hours a year. That is a lot of equipment to install for marginal benefit.

Dual-fuel makes sense when:

• You already have a working gas furnace that is less than 7 years old and you want to add cooling/efficiency by installing the heat pump alongside it.
• You have a large or poorly insulated home where the load on the coldest nights truly exceeds heat pump capacity.
• You travel and want belt-and-suspenders heating reliability when no one is home to notice a problem.

Otherwise, a straight heat pump install is simpler, cheaper to maintain, and equally comfortable.

Bottom line: which to pick

Here is the decision tree we actually use during in-home consults:

• Existing gas furnace, 15+ years old, AC also aging: Replace with a heat pump. Single best move in HVAC right now.
• Existing gas furnace, under 7 years old, AC failing: Install a heat pump alongside the furnace as dual-fuel. Keep the working asset, gain the efficiency.
• No existing gas service: Heat pump, no question. Do not run a new gas line for a furnace in 2026.
• All-electric home with old electric resistance furnace: Heat pump. Your operating cost will drop by 60% or more.
• New construction: Heat pump unless the builder has already trenched gas and you genuinely prefer combustion heat.
• Geothermal-suitable lot (acreage, willing to invest): Look at geothermal heat pumps. Even better COP, longer equipment life, premium upfront cost.

For nearly every Washington, Hurricane, and St. George homeowner replacing aging equipment, the answer is a heat pump.

Get an honest assessment from M&M Mechanical Inc.

We have been installing heating systems in Washington County since 1992. We installed gas furnaces for 30 years and we still install them when they are the right call. But the technology and the economics have shifted, and we are not going to recommend a furnace just because that is what we have always done.

If your furnace is on its last legs, or you are just curious what your specific home would look like on a heat pump, we offer free in-home assessments. We measure your ducts, run a Manual J load calculation, look at your panel, pull your last 12 months of utility bills, and give you an itemized written quote covering both options. No pressure, no upsell. You get the numbers, you make the call.

Call (435) 674-1275 or stop by our office at 1430 Rio Virgin Drive, Washington, UT 84780. We can usually schedule an in-home visit within a week.

Already maintaining the system you have? Make sure you are on a year-round HVAC maintenance schedule so it goes the distance. And if you want to dig deeper into our heat pump installation process or full heating service offerings, those pages cover the specifics.