What Is COP — and Why It Matters

🕒 Read Time: 6 to 7 min

COP measures heat pump efficiency and why modern systems outperform gas furnaces.

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What Is COP (Coefficient of Performance) — and Why It Matters for Your Heat Pump

If you’ve started researching heat pumps, especially modern or cold-climate models, you’ve probably seen the term COP, short for Coefficient of Performance. It often gets mentioned in technical articles or manufacturer literature, but rarely explained in a way that connects to what homeowners actually care about: comfort, reliability, and energy costs.

COP is one of the most important concepts to understand when comparing heat pumps to older systems — and even to high-efficiency gas furnaces. Once you understand how COP works, it becomes much easier to see why today’s heat pumps perform so much better than the ones installed 10 or 15 years ago.

COP, Explained in Plain Language

COP measures how efficiently a heat pump converts electricity into heat. More specifically, it tells you how many units of heat the system delivers for every unit of electricity it consumes.

If a heat pump is operating at a COP of 3, it means the system is delivering three units of heat for every one unit of electricity used. That’s three times more heat than what electric resistance heat can provide using the same amount of power.

This is where many homeowners get confused — and understandably so. Getting more heat than the energy you pay for sounds impossible. But the key detail is this: a heat pump doesn’t create heat.

Why Heat Pumps Can Be So Efficient

Unlike furnaces or electric heaters, heat pumps move heat rather than generate it. Even when it feels cold outside, the air still contains heat energy. A heat pump uses electricity to capture that heat and transfer it into your home.

Because the electricity is used to move heat instead of create it, the system can deliver two, three, or sometimes even four times the heat compared to the electricity it consumes. That’s why heat pumps can achieve COP values well above 1.

By comparison, electric resistance heat — like baseboard heaters or electric backup strips — always operates at a COP of 1. Every dollar you spend on electricity gives you an equal amount of heat. No gain, no efficiency boost.

COP Isn’t a Fixed Number

One important thing to understand is that COP changes based on outdoor conditions. It’s not a single rating that applies all winter long.

In milder winter weather, typically in the 40–50°F range, modern heat pumps often operate at very high COP levels. This is when they’re at their most efficient, delivering excellent comfort at a low operating cost.

As outdoor temperatures drop, there’s less heat available in the air, so COP gradually decreases. Older heat pumps experienced a sharp drop in efficiency around freezing temperatures, which is why many homeowners associate heat pumps with high winter electric bills.

Modern cold-climate heat pumps are designed to slow that decline. Advances in compressor technology, refrigerants, controls, and defrost strategies allow today’s systems to maintain useful COP values much deeper into winter.

COP vs. Gas Furnace Efficiency

Gas furnaces measure efficiency differently, using a percentage called AFUE. An 80% AFUE furnace converts about 80% of the fuel it burns into usable heat. High-efficiency furnaces may reach 95% or slightly higher, but they can never exceed 100% efficiency because combustion always involves losses.

Heat pumps aren’t limited in the same way.

When a heat pump operates at a COP of 2, it’s effectively delivering 200% efficiency. At a COP of 3, it’s delivering three times as much heat energy as the electricity it uses. This difference explains why heat pumps often cost less to operate than gas furnaces during mild to moderate winter temperatures.

It’s not that gas furnaces are inefficient — they’re actually very good at what they do. It’s that moving heat is inherently more efficient than creating it.

What Happens in Cold Weather

As temperatures drop further into winter, a gas furnace maintains roughly the same efficiency, while a heat pump’s COP continues to decline. That doesn’t mean the heat pump stops working — it simply becomes less efficient as outdoor air contains less available heat energy.

This is where system design matters.

Modern cold-climate heat pumps are engineered to maintain heating performance well below freezing, with COP staying higher at lower temperatures than older designs could manage. In many Missouri homes, this allows a heat pump to handle the majority of the heating season efficiently before supplemental heat is needed.

For homeowners who want added flexibility, pairing a heat pump with a gas furnace in a dual-fuel system provides the best of both worlds. The heat pump runs during periods when COP is high and operating costs are lowest, while the furnace steps in during the coldest conditions.

Why COP Matters for Comfort, Not Just Cost

COP doesn’t just affect energy bills — it affects how your home feels.

Heat pumps that operate at higher COPs can run longer at lower speeds, delivering steady, even heat instead of short bursts. This reduces temperature swings, minimizes drafts, and creates a more comfortable indoor environment.

Older systems that rely heavily on backup heat tend to cycle more aggressively, which can lead to hot-then-cold patterns and uneven room temperatures. Modern systems designed to maintain higher COP longer avoid those issues.

Real-World Factors That Affect COP

While manufacturers publish performance data, real-world COP depends on several factors inside your home. Proper equipment sizing, duct design, insulation levels, air sealing, and thermostat setup all influence how efficiently a heat pump operates.

A system that’s oversized or poorly installed may never reach its potential COP, even if the equipment itself is high quality. That’s why professional system design and installation matter just as much as choosing the right model.

The Bottom Line for Homeowners

COP helps answer one of the most important questions when considering a heat pump: how efficiently will this system heat my home in real winter conditions?

Understanding COP explains why modern heat pumps are no longer limited to mild climates. With today’s technology, properly designed systems can deliver reliable, comfortable heating with competitive operating costs — even in regions with cold winters like Missouri.

At SS&B Heating & Cooling, we help homeowners look beyond the buzzwords and understand how efficiency numbers translate into real performance. Whether you’re replacing an older heat pump, considering a gas furnace alternative, or exploring a dual-fuel setup, we’ll help you choose a solution that fits your home, your comfort goals, and your energy costs.

If you’re curious how your current system stacks up or want to explore modern heat pump options, our team is always happy to help.

Call us to stay warm and safe! 417-866-0990, Have questions? Fill out our online contact form for assistance!

The information above reflects general heat pump performance principles and typical operating conditions. Actual efficiency and comfort depend on proper system design, installation, and home characteristics.

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