Heat pumps vs. air conditioners: Key differences

Table of contents

1. How does a heat pump work?

2. How does a heat pump heat?

3. The pros & cons of heat pumps

4. What is air conditioning (AC)?

5. How does an air conditioner cool?

6. Pros & cons of air conditioners

7. The differences between a heat pump and an air conditioner

8. Heat pumps vs. ACs: Costs

9. Choosing the best solution

10. Why hire a pro to install a heating or cooling system in your house?

If you think about replacing your current HVAC unit, the chances are that you’ve already heard many conflicting opinions about the most common types of solutions. Should you install a heat pump or air conditioner? Although these systems have a lot in common, they are not the same and offer different advantages.

A system that works perfectly in a particular situation may be completely inefficient in other circumstances, so you should make the right choice based on your specific needs. Let's dive into the theory of what a heat pump is and how it differs from an air conditioner. To understand which system would fit you best, you should learn as much as possible about its key features, advantages, and weak points. This is what this guide sheds light on.

How does a heat pump work?

Let's first discuss a heat pump because if you want to cool your home, the chances are that the first thing that pops into your mind is air conditioning. Although heat pumps can cool, they can also heat the premises. These units can transfer warm air from the outside to heat a building, but they can also do the opposite to cool it down.

If you have some basic understanding of how an AC system works, you already know a lot about the heat pumps' operational principles because they have many in common. However, if you have no idea how these systems work, don't worry because we will explain that further in the text.

There are different kinds of heat pumps, but they have the same underlying principle of work, which is heat transfer. Such a system is different from other heating solutions because it moves heat between the two areas instead of generating heat by burning fuel. As a result, a heat pump needs less energy, which is also one of the advantages of a heat pump over other heating solutions.

According to thermodynamics, heat moves from areas with a high temperature to areas with lower temperatures. A heat pump does the opposite, therefore being able to heat your home. The most common source of heat is air. In this case, a heat pump moves heat from the air outside your home through coils filled with a refrigerant. Such a system has a lot in common with what you can see in the back of your fridge.

How does a heat pump heat?

Now let’s take a closer look at the elements of a heat pump system. A typical air-source heat pump consists of two parts: an outdoor unit and an indoor unit. The former looks similar to an outdoor unit of a split air conditioner, and the latter helps distribute air and heat through your home or office.

• The outdoor unit includes a fan and a coil. The coil may work as an evaporator when a heat pump works in a heating mode or as a condenser in a cooling mode. The fan moves air through the coil to ensure heat exchange.
• The indoor unit, also called the air handler, comprises a fan and a coil. The coil works as a condenser in the heating mode and as an evaporator in the cooling mode.
• The heat in heat pumps is absorbed or rejected by the refrigerant as the air moves through the system by a compressor.
• A reversing valve reverses the refrigerant flow in a heat pump to switch between cooling and heating modes.
• An expansion valve helps regulate the refrigerant flow when it moves through the system, reducing its temperature and pressure.

In the heating mode, pumps use the air outside your home as a source of heat energy, even when it’s cold outside. To make it possible, the coil of the outside unit works as an evaporator while the indoor coil works as a condenser.

A cool liquid refrigerant absorbs heat energy outdoors and turns it into a cold gas. After this, the cold gas becomes hot because of the pressure applied to it, and then it is cooled down in the indoor unit, passing its heat to the air. The gas turns into warm liquid, and low pressure makes it move back to the outdoor unit, where it cools down, so the cycle repeats.

The pros & cons of heat pumps

Let’s start with the advantages of heat pumps. You may want to consider them when choosing between a heat pump and air conditioning and searching for the best heating solution.

Pros

• Heat pumps can be used all year long. They don’t require you to install two separate systems for different seasons. While heat pumps can work in a cooling mode, heat pumps and air conditioners are different because the former can also provide heat.
• Heat pumps are more environment-friendly and energy-efficient than gas-operated furnaces. Besides, electricity generally costs lower than natural gas. That is why heat pumps could have a lower yearly cost of operation.
• Given that two systems are combined in the same unit, you can save money on maintenance if you need both cooling and heating systems.

Cons

• Unlike air conditioners, heat pumps always require installing outdoor and indoor units.
• Heat pumps aren’t efficient in areas where temperatures often drop below freezing, so you may opt for a furnace if you need a heating solution. If you also want to keep your home cool in summer, you can buy an air conditioner separately.
• Compared to air conditioners, heat pumps require more maintenance and cost more to install.

What is air conditioning (AC)?

Air conditioning systems remove heat and moisture from an inside space, cooling it down. An air conditioner moves air through the system and blows cold air. This becomes possible by cooling down fluid through evaporation of the refrigerant. An AC turns gas into a liquid and back, making such systems similar to heat pumps.

The key elements of an air conditioner are:

• a condensing unit with a condensing coil, which is usually located outside
• a compressor that moves the refrigerant through the system
• a fan that blows air over the hot coil and transfers the heat to the outdoor air
• an expansion valve that regulates the flow of the refrigerant
• an air handler that distributes cool air inside

How does an air conditioner cool?

The refrigerant arrives at the compressor at low pressure as a gas. The compressor applies pressure to turn this gas into a liquid. As a result, the temperature rises, and the liquid moves away from the compressor as a hot gas. This gas reaches the condenser, turning into liquid again and then moving through the evaporator. Its pressure drops, and it starts to evaporate. The cycle repeats when the refrigerant gets back to the compressor.

During this process, the air conditioner removes heat from the air and uses it to cool gas in the evaporator. After this, the air conditioner blows cool air back into your home. As you can see, the main difference between a heat pump and air conditioning is that an AC doesn’t do the opposite.

Pros & cons of air conditioners

If you’re looking for a heating system, you will have to purchase it separately. However, if you only need something to feel comfortable in summer, an air conditioner offers some advantages.

Pros

• If you already have a heating system in your home, an air conditioner can easily satisfy your cooling needs.
• Air conditioners have lower upfront costs and offer the most cost-effective way to cool your home.
• Air conditioners generally take less space than heat pumps, so if you’re looking for something compact, an air conditioner might be the best option.

Cons

• An air conditioner can be pretty noisy, so it is not recommended to install it near a room where you spend a lot of time.
• An air conditioner also requires proper maintenance. It may accumulate a lot of moisture, creating a perfect breeding environment for bacteria.
• Most air conditioning units cannot be used for heating.

The differences between a heat pump and an air conditioner

To replace the existing HVAC unit, you need to choose a system that will be efficient in particular circumstances, fulfilling your specific needs, whether air conditioning only or cooling. As you can see, ACs and heat pumps offer different advantages.

Central air conditioning systems and heat pumps involve transferring heat from one area to another. For instance, an air conditioner transfers heat from the inside of your home to the outside. The main difference between these two systems is that heat pumps can also move the air, and therefore heat, in a reverse direction. While some models of air conditioners have heat strips in the air handler unit, most air conditioning systems aren’t capable of heating.

Heat pumps vs. ACs: Costs

While the cost of an average heat pump system is only about 5% higher than that of an air conditioner, you should keep in mind that you will also pay more for installation when choosing a heat pump. Given that heating units are used all year round, they also have a shorter lifespan than air conditioning systems. As a result, you may also pay more for their upkeep.

If you’re going to install a new HVAC unit or replace the existing one, we recommend you request an estimated cost. However, you should keep in mind that the final price will depend on many factors, including the climate in your area and specific parameters of your home or office.

Choosing the best solution

To choose whether you should have a heat pump or an air conditioner, you should consider the climate in your area. An air conditioner can only cool the air inside the room, so a heat pump is a more flexible solution if you want to keep it warm when it’s cold outside.

On the other hand, if you live in an area where the temperature drops below 40 degrees, a heat pump won’t be an efficient heating option. Such a system needs to work hard to maintain the necessary temperature. It will use more energy than other heating systems, increasing your utility bills.

The thing is that when the temperature drops below 40, the system transferring heat becomes insufficient to warm the inner space. In this case, pumps usually switch to an emergency mode and start to heat the air with heat strips that consume a lot more electricity.

In other words, even though an air conditioner won’t heat your home in winter, if the climate is too cold, a heat pump also won’t be a good solution. In this case, you may opt for an air conditioning system to cool your place in summer and purchase a separate heating unit for the winter. For example, you may consider purchasing a boiler or furnace.

However, if you live in an area with a moderate climate, both an air conditioner and a heat pump will demonstrate almost the same cooling performance. An air conditioner won't help you heat your place, while a heat pump can fulfill this purpose unless it's too cold outside. An AC, however, is a less costly solution.

Why hire a pro to install a heating or cooling system in your house?

Both air conditioning systems and heat pumps require proper installation with meticulous attention to detail. It's a labor-intensive process that should be performed by contractors with extensive expertise, which is a reason why installation costs can be quite high. Therefore, it's crucial to find a certified installer who can prove their expertise while not demanding an exorbitant price for their services.

We already mentioned possible noise as one of the disadvantages of air conditioners. Those who opt for a heat pump may also experience the same issue if their system isn't correctly installed. Besides, your HVAC unit's safety and effective operation also depend on the contractor's workmanship.

To choose the best contractor, you may need to analyze multiple offers, familiarize yourself with the market prices, and make dozens of phone calls. Fortunately, contractor-matching platforms like MyHomeQuote offer a simpler solution. With us, you just need to provide details about your project to let the platform match you with contractors who have the necessary experience and good reviews from clients.

No matter what kind of HVAC system you choose, on MyHomeQuote, you can find a contractor who has good experience in installing this exact kind of system and whose rates fit your budget. Leave your request now to avail yourself of lucrative offers from local experts.