What Is a Heat Pump And How Does a Heat Pump Work?
A heat pump is a versatile HVAC system that heats and cools your home by transferring heat rather than burning fuel. In the summer, it acts like an air conditioner, removing heat from your home. In the winter, it reverses the process, extracting heat from the outdoor air to warm your home efficiently.
How do heat pumps work?
Heat pumps work by moving heat from one place to another using electricity and refrigerant. They do not generate heat; they transfer it. Because of this process, heat pumps can achieve efficiency ratings of 300% to 500% 1, meaning they can deliver three to five units of heat energy for every unit of electricity they consume. By comparison, a traditional gas furnaces typically tops out at about 98% efficiency because it generates heat through fuel combustion.
How does a heat pump work in simple terms?
Think of a heat pump as a two-way air conditioner. In the summer, it pumps heat out of your house to cool it down. In the winter, it pumps heat into your house—even from cold outdoor air—to warm it up.
Curtis Herchenbach, owner of Herchenbach Mechanical in Gurnee, IL, explains that a heat pump is functionally similar to an AC unit but with a crucial advantage:
The heat pump simply reverses the refrigerant flow to flow in the opposite direction. This makes the indoor coil get hot and the outdoor unit get cold so you can heat with electricity.
The Heating and Cooling Cycle
Heat energy naturally moves to areas with lower temperatures and lower pressure. Heat pumps leverage this physical property to provide comfort year-round.
- Cooling Mode: The system absorbs heat from inside your home and releases it outdoors, just like a standard air conditioner.
- Heating Mode: The system reverses operation. It absorbs heat energy from the outside air (or ground) and transfers it indoors.
Types of Heat Pumps
Choosing the right system depends on your climate, home size, and efficiency goals. The three main types are:
1. Air-Source Heat Pumps
Air-source heat pumps transfer heat between indoor air and outdoor air. They are the most common type for residential heating and cooling.
2. Geothermal (Ground-Source) Heat Pumps
Geothermal heat pumps transfer heat between your home and the ground. While heat pump installation costs are higher, they offer superior efficiency and lower operating costs due to consistent ground temperatures. Carrier's GCA Infinity Geothermal Heat Pump offers cooling efficiencies of up to 37 EER and heating efficiencies up to 5.2 COP, helping reduce energy costs while adhering to eco-friendly practices.
3. Ductless Mini-Splits
A ductless mini split is an ideal solution for homes without ductwork. It delivers conditioned air directly to individual rooms, offering flexible comfort control. Learn more about how ductless mini split heat pumps work.
Learn more in our guide on heat pump types.
Important Components of a Heat Pump System
Understanding the parts of your system helps in maintenance and troubleshooting. A typical air-source system includes:
- Outdoor Unit: Contains a coil (condenser in cooling/evaporator in heating) and a fan to facilitate heat exchange with outside air.
- Indoor Unit (Air Handler): Contains a coil and fan to move air through your home's ducts.
- Refrigerant: The substance that absorbs and rejects heat as it circulates through the system.
- Compressor: Pressurizes the refrigerant to move it through the coils.
- Reversing Valve: The critical component that switches the flow of refrigerant, allowing the system to change from cooling to heating.
- Expansion Valve: Regulates refrigerant flow, reducing pressure and temperature to prepare the refrigerant for heat absorption.
Where do heat pumps work best?
Heat pumps are effective in a wide range of climates.
- Moderate Climates: Heat pumps are extremely cost-effective and efficient where temperatures rarely drop below freezing.
- Colder Climates: Modern cold climate heat pumps can operate efficiently even in freezing temperatures (the Carrier 27VNA1 provides heating operation down to -23° F).
- Dual Fuel Systems: In regions with extreme cold, a heat pump can be paired with a gas furnace. This dual fuel system leveraging Carrier's Hybrid Heat Technology maximizes efficiency by using the heat pump for mild days and the furnace for the coldest days.
Heat Pump vs. Furnace vs. AC
Heat pumps, furnaces and air conditioners differ in how they heat or cool your home, how efficiently they use energy and how long they typically last. The table below compares key performance metrics, including SEER2, HSPF2, and system lifespan to help you understand how heat pumps compare with other HVAC options.
| System | Primary Function | Typical efficiency metric | Carrier Infinity line efficiency | Typical lifespan |
| Heat pump | Heating + cooling | SEER2/HSPF2 | 23 SEER2/10.5 HSPF2 | 10-15 years |
| Gas furnace | Heeating | AFUE | 98.5% AFUE | 15-20 years |
| Central air conditioner | Cooling | SEER2/EER2 | 21 SEER2/12 EER2 | 15-20 years |
1 https://www.energystar.gov/products/air_source_heat_pumps
Frequently Asked Questions
A heat pump is an HVAC unit that heats and cools your home by transferring heat energy between the indoors and outdoors using electricity and refrigerant.
In winter, a heat pump extracts heat energy from the cold outdoor air and transfers it inside to warm your home. Even cold air contains heat energy that the system can capture.
Heat pumps move heat rather than creating it by burning fossil fuels, making them more energy-efficient and environmentally friendly than traditional furnaces.
With proper maintenance, a high-quality heat pump typically lasts about 15 years. Learn more about heat pump lifespan.
While they run on electricity, heat pumps are highly efficient. By transferring heat instead of generating it, they can deliver up to three times more heat energy than the electrical energy they consume.
About The Author: Ryan Mayes is a Senior Digital Brand Marketing Manager at Carrier who focuses on creating clear, helpful resources on HVAC topics. Ryan’s goal is to guide readers toward smart, confident decisions about their indoor comfort.
About The Expert Reviewer: Zach Dickey is a Product Manager for Residential Heat Pumps at Carrier Corporation, where he helps develop innovative heating and cooling solutions that meet homeowners' evolving comfort needs while aligning with industry trends, energy efficiency standards, and regulatory requirements.