What is a Heat Pump & How Do They Work?

Looking for an energy-efficient way to regulate the temperature in your home? Then you might want to consider investing in a heat pump system.

Despite the name, heat pumps can be used for cooling as well as heating. In this handy guide, we’ll cover the following:

How a heat pump works
Explore efficiency throughout the seasons
Examine some pros and cons to help you decide whether it’s the right choice for your home

What is a heat pump?

A heat pump is an energy efficient HVAC system that has both heating and cooling functions. This separates heat pumps from central air conditioners, furnaces, and boilers that are capable of only heating or cooling.

A typical heat pump system looks similar to a split AC system with one indoor and one outdoor unit. However, unlike traditional heating and cooling systems, heat pumps don’t actually generate hot or cold air. Rather, they transfer heat from one location to another between the units.

During warmer months, heat pumps extract heat from indoors and transfer it outside. In colder months, the process is reversed, meaning the system absorbs heat from the outdoor air and transfers it indoors to warm the space.

How does a heat pump work?

The methodology of how a heat pump works will depend on the type of system you install:

Air-source heat pumps move warm air from outside to inside environments.
Ground-source heat pumps (also known as geothermal heat pumps) extract heat from thermal energy stored in the ground and transfer it to indoor spaces.
Water-source heat pumps absorb heat from outside water sources like wells, ponds, and lakes and direct it indoors.

The go-to choice for most homeowners is an air-source heat pump, mainly because they’re relatively straightforward and inexpensive to install. Plus, not all homes have access to water sources or adequate outdoor space to support water or ground-source heat pump installation.

Regardless of the heat source, each type of heat pump works in roughly the same way. Let’s start by explaining the heating mode before considering how heat pumps can also act as a cooling system.

Here’s a step-by-step explanation of how it all works:

Step 1: Heat from the air, ground, or water is transported into the house from the outside unit via a liquid refrigerant.
Step 2: The heat pump’s compressor condenses the refrigerant, raising its temperature.
Step 3: The liquid bypasses a reversing valve and enters the indoor unit (because at this point, we’re looking to create heat, not cool the house down).
Step 4: Cool air is blown over the heat exchange surface to remove some of the thermal energy and deliver warm air into the room.
Step 5: The refrigerant continues on its journey, now slightly cooler, and passes through an expansion valve, where temperature and pressure are reduced so that it becomes part liquid, part vapor.
Step 6: When it returns to the outdoor unit, it passes through a heat exchanger where the outside ambient air converts it to a low-pressure, low-temperature vapor.
Step 7: The vapor is passed back to the compressor, where the cycle begins again.

It’s essential to note that the heat produced by heap pumps isn’t only for warming rooms via the inside unit. The hot air can also be transferred to the central heating system to provide hot water for taps, underfloor heating systems, radiators, and more.

So, that’s the heating mode explained. But what does a heat pump do when it’s switched to cooling mode? The short answer is: exactly the same thing with the refrigeration cycle reversed. When the reversing valve is open, the heat exchangers and other internal valves simply work in opposite directions to remove rather than generate heat.

Are heat pumps efficient?

Heat pumps are well-recognized for their energy efficiency in both heating and cooling operations. However, overall efficiency and longevity can be affected by:

Climate
Insulation levels
Unit size
Installation quality

Provided that heat pump installation is conducted by a qualified professional, you should be assured of proper sizing, adequate insulation, and the right system settings to facilitate optimum heat flows for both hot and cold air. So, in most instances, climate considerations are the primary concern. Let’s take a closer look at how seasonal variations might affect cooling and heating system efficiency.

Are heat pumps efficient in hot weather?

The short answer is yes. However, just like with other heating systems, a heat pump will have to work harder the hotter it gets. Air-source models, in particular, may be challenged by extreme summer weather because high temperatures reduce the differential between the outside air and the refrigerant in the heat pump, which lowers efficiency.

If you live in a particularly hot area, it’s essential you check Seasonal Energy Efficiency Ratio (SEER) and Heating Seasonal Performance Factor (HSPF) ratings before you have heat pumps installed. Higher SEER and HSPF ratings indicate better efficiency in hot weather conditions.

Other steps you could take to ensure optimal operational efficiency include:

Ensuring ample shade for the outdoor unit to prevent overheating
Regularly cleaning and replacing air filters to maximize airflow
Adjusting thermostat settings or investing in a programmable or smart thermostat to minimize the cooling load during peak hours
Minimizing heat gain in your home by sealing air leaks, installing reflective window treatments, and using ceiling fans to promote airflow

Are heat pumps efficient in cold weather?

Again, yes. But exactly how does a heat pump work in winter when the air outside is cold?

Even when it’s cold outside, heat energy is still present — although admittedly, the refrigeration process may be less efficient at transferring heat than in milder conditions. Therefore, households expecting particularly harsh winter weather might consider a hybrid heat pump system as an all-encompassing solution.

Hybrid heat pumps combine a furnace or gas boiler for supplemental heating. This allows you to use the pump only to cool and rely on the furnace to warm your house during winter and chilly evenings.

Heat pump pros and cons

Let’s take a look at a comprehensive list of pros and cons to see how heat pumps stack up against alternatives and more traditional systems.

What are the advantages of a heat pump?

Long lifespan – Most heat pumps come with a 5-year warranty. However, modern systems should last 15-20+ years when properly maintained.
Energy efficiency – Zoning options on ductless heat pumps allow for customization between individual rooms to ensure you don’t waste heat.
Quiet operation – Heat pumps produce minimal noise compared to air conditioners and traditional HVAC units with loud compressors.
Cost efficiency – By transferring heat rather than generating it, heat pumps can make significant energy savings, resulting in lower utility bills.
Financial incentives – Various federal and local schemes offer rebates and tax credits to offset the upfront cost of installation.
Environmental benefits – Because they use renewable types of heat from air, ground, and water sources, heat pumps reduce greenhouse gas emissions and fossil fuel reliance.

What are the disadvantages of a heat pump?

Initial costs – Without financial incentives, purchasing, and installation costs are typically higher than with traditional heating and cooling alternatives.
Performance limitations – While effective in moderate climates, heat pumps tend to operate with reduced efficiency in extreme temperatures.
Compatibility issues – Additional heat pump work like ducting and electrical wiring may be required to retrofit your home beyond its existing infrastructure.

Are heat pumps good in Texas?

Texas is known for its hot summers and mild winters, making heat pumps a popular option. In fact, many Texans already rely on heat pump technology, and with nearly 2 million systems installed, there are more heat pumps in Texas than in any other state.

As technology develops further, heat pump balance points are likely to become even higher. What is a heat pump balance point? Short version – it’s the outdoor temperature at which it reaches capacity for effective cooling. This, combined with effective winter operation down to -10 °F, makes heat pumps an increasingly viable option for residents looking to upgrade their existing heating system as climate change continues to make Texas weather patterns even more unpredictable and extreme.

Affordable energy plans from BKVE

At BKV Energy, we understand the importance of affordable energy. That’s why we’re committed to offering tailored solutions to meet an array of needs and budgets.

By harnessing the power of innovative technologies like heat pumps and pairing them with straightforward energy plans, Texans can enjoy year-round comfort without breaking the bank.

Ready to make greater home energy savings and reduce your utility bills? Enter your zip code to explore our range of low-cost, gimmick-free electricity plans today.

Written by Graham Lumley

Graham Lumley, Growth Product Manager at BKV Energy, leads digital and traditional marketing strategies, focusing on educating Texans about the state's deregulated energy market. With over 10 years of marketing experience, he creates content to help consumers understand and save on their energy bills, bringing a fresh and dynamic approach to the industry.