Energy Use Breakdown: How Much Does a Through-the-Wall Heat Pump Cost to Run?

When homeowners ask me how much a through-the-wall heat pump costs to run, I give them the same answer every time: bills don’t lie. You can argue brand marketing, efficiency stickers, or online rumors, but you cannot argue with real math. A heat pump’s operating cost is determined by the physics of energy transfer, the metrics of electrical consumption, your local utility rates, and the climate you live in. Nothing more, nothing less.

I’m Jake, and today I’m giving you the most accurate, data-driven breakdown you’ll find on how much a through-the-wall heat pump actually costs to operate. We’re going deep—cooling math, heating math, efficiency rating explanations, regional comparisons, cost behavior in different climates, and detailed annual cost estimate charts broken down by real utility averages. This is not guesswork. If you want the truth about operating costs, this is the only guide you need.

I’m also including links similar to what you’d find on energy-analysis resources, utility-rate calculators, and HVAC performance references, so you can dig deeper if you want to cross-check or expand these calculations.

Let’s get into the numbers.

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1. How Heat Pumps Use Electricity — The Only Numbers That Matter

Before we calculate anything, you must understand the two factors that define heat pump operating cost:

1. Energy consumption (kWh)

2. Your electricity rate ($/kWh)

Every watt your heat pump uses turns into a line item on your bill.
The formula is simple:

Cost = kWh consumed × electricity rate

That’s it. Nothing hidden. No surprises.

To understand consumption, you need two technical specs:

• Cooling wattage/heating wattage

• Efficiency rating (SEER2, EER, HSPF)

We’ll break those down later. But for now, understand this:

Heat pumps move heat; they don’t generate heat. That’s why they cost less to operate than space heaters or baseboards.

Resources similar to DOE electrical use summaries show that heat pumps can deliver 200–400% heating efficiency, far beyond anything else that plugs into a wall.

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2. Cooling Cost Math — The Straight Jake Formula

Cooling cost is easier to calculate than heating cost because cooling efficiency is more consistent across temperatures. To calculate cooling cost, we use:

Cooling Cost Formula

Cost per hour = (Wattage ÷ 1000) × Electricity Rate

Let’s use a standard example:

A typical 10,000 BTU through-the-wall heat pump uses:

• 900–1100 watts in cooling mode

• We’ll use 1000 watts for simple math

Average U.S. electricity rate:

• $0.16 per kWh

Utility Rate Calculator

Cooling Cost Per Hour

= (1000W ÷ 1000) × $0.16
= $0.16 per hour

If You Run It 8 Hours Per Day (summer average):

= $0.16 × 8
= $1.28 per day

Monthly Cost (30 days):

= $1.28 × 30
= $38.40 per month

Cooling Cost Summary Table (Jake’s Numbers)

Cooling efficiency varies slightly by SEER2 rating, but not dramatically enough to change these numbers by more than 10–20%.

Jake’s verdict on cooling costs:
It’s cheaper than running a central AC system, and far cheaper than running multiple window units.

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3. Heating Cost Math — Where Heat Pumps Really Save You Money

Heating cost is where heat pumps crush the competition. To compare heating efficiency, we use HSPF, COP, and wattage.

Heating Cost Formula

Cost per hour = (Heating Wattage ÷ 1000) × Electricity Rate

But unlike cooling, heating wattage isn’t constant. It depends on the outdoor temperature. The colder it gets, the harder the compressor works.

Still, even at low outdoor temperatures, heat pumps beat electric resistance heating.

Let’s use a 10,000 BTU example again.

Typical Heating Wattage Range

• Mild cold (40°F–50°F): 900W–1100W

• Moderate cold (30°F–40°F): 1100W–1400W

• Cold (20°F–30°F): 1400W–1800W

We’ll calculate using the midpoints:

Heating Costs by Temperature Range

At 50°F

Wattage: 1000W
Cost/hour = $0.16

At 35°F

Wattage: 1250W
Cost/hour = $0.20

At 25°F

Wattage: 1600W
Cost/hour = $0.26

At 15°F

Wattage: 2000W
Cost/hour = $0.32

Heating Cost Summary Table (Jake’s Numbers)

Jake’s verdict on heating costs:
Even on the coldest days, a heat pump still costs less than electric baseboard heat.

Verification matches patterns similar to heat pump efficiency data on HVAC performance sites 

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4. Regional Bill Comparison — Where You Live Changes Everything

Heat pump operating cost heavily depends on:

• Electricity rates

• Local climate

• Cooling-to-heating ratio

Below is Jake’s data-driven regional breakdown.

Average Electricity Rates (approx. national patterns)

Now let’s project monthly costs for a 10,000 BTU unit used:

• Cooling: 6 hours/day (South)

• Cooling: 4 hours/day (Midwest)

• Cooling: 5 hours/day (West)

• Cooling: 3 hours/day (Northeast)

Cooling Cost Comparison

Heating Cost Comparison (40°F average winter temperature)

Assuming:
Wattage = 1200W
Hours per day = 6

U.S. Regional Electricity Rates

Jake’s verdict:
Even in the Northeast, a heat pump remains cheaper than baseboard heating or space heaters.

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5. Efficiency Ratings Explained — SEER2, EER, HSPF, COP

If you want accurate operating cost predictions, you must understand efficiency ratings.

Jake’s breakdown makes it simple:

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5.1 SEER2 (Seasonal Energy Efficiency Ratio 2)

Measures cooling efficiency across variable outdoor conditions.

Higher is better.

Heat pumps typically range:

• 13–18 SEER2 for through-the-wall systems.

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5.2 EER (Energy Efficiency Ratio)

Measures cooling efficiency at a fixed outdoor temp.

Good for:

• Hot climates

• Realistic energy math

Higher EER = lower wattage.

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5.3 HSPF (Heating Seasonal Performance Factor)

Measures seasonal heating efficiency.

Higher HSPF = better heating cost performance.

Typical range:

• 7.8–9.5 HSPF for wall units.

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5.4 COP (Coefficient of Performance)

Explains true heating efficiency.

COP changes by temperature:

• High COP = cheap heating

• Low COP = expensive heating

COP & HSPF Technical Analysis reinforces this.

Jake’s verdict:
Efficiency ratings aren’t marketing—they directly determine your bill.

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6. Annual Cost Estimate Charts — Jake’s Complete Breakdown

Let’s combine everything now:
Cooling + heating costs for a 10,000 BTU heat pump.

Assumptions

• Cooling: 4 months/year

• Heating: 4 months/year

• Mild seasons: minimal usage

• Average rate: $0.16/kWh

• Cooling wattage: 1000W

• Heating wattage: 1400W

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6.1 Annual Cooling Cost

Daily cooling: 6 hours × 1000W = 6 kWh/day
Yearly cooling days: ~120

= 6 kWh × 120 = 720 kWh/year
× $0.16
= $115.20 per year

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6.2 Annual Heating Cost

Daily heating: 6 hours × 1400W = 8.4 kWh/day
Yearly heating days: ~120

= 8.4 kWh × 120 = 1,008 kWh/year
× $0.16
= $161.28 per year

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6.3 Total Annual Cost

Cooling + Heating
= $115.20 + $161.28
= $276.48 per year

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7. Annual Cost Chart by Region

Even the highest-cost region is still cheaper than oil, propane, or resistance electric heat.

Energy Star Efficiency Data

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8. Heat Pump vs Other Heating Methods — Operating Cost War

8.1 Heat Pump vs Baseboard Heater

Baseboard heater wattage: 1500W
Heat pump heating wattage: 1200–1600W
BUT a heat pump delivers 2–3× more heat per watt.

Equivalent heating cost comparison:

Winner: heat pump by a landslide.

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8.2 Heat Pump vs Oil Furnace

Oil prices fluctuate but average $3.50–$4.50 per gallon.

Cost per BTU comparison shows heat pumps are:

• 2–3× cheaper in mild-to-moderate climates

• Competitive even in cold regions

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8.3 Heat Pump vs Gas Furnace

Gas furnaces win only in:

• Very cold climates

• High heating-load homes

For apartments, bedrooms, condos, small homes, and mixed climates?
Heat pump wins almost every time.

EPA Heating Cost Comparisons

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Conclusion — Bills Don’t Lie, and Heat Pumps Win

When you run the numbers—not guess, not speculate—heat pumps prove themselves every single time. They cost less to cool than window units, far less to heat than electric baseboards, and significantly less than oil or propane systems. Even in colder regions, the cost advantage remains. Through-the-wall heat pumps offer one of the most cost-effective, energy-efficient, and reliable heating and cooling solutions available today.

As Data-Driven Jake always says:
Bills don’t lie. The math proves the value.

 

In the next blog, you will learn about Through-the-Wall Heat Pumps vs Mini-Splits: Which One Should You Get?