What Is Auxiliary Heat on a Heat Pump?

Warmth pumps are a great way to warmth your residence. They use the temperature variation among the outdoors and inside of to transfer warmth to or from a developing. At times, your heat pump might have temperature changes to warm or awesome your property. It does this when responding to shifting temperatures.

In the course of the wintertime months, auxiliary warmth kicks in routinely and assists keep your house warm even though minimizing your energy monthly bill. If you are questioning what auxiliary heat is or how your warmth pumps use it, you have appear to the correct location!

We’ll describe what auxiliary heat is and how it works in a warmth pump. Also, we’ll go over a variety of facets of a heat pump to assist you comprehend auxiliary warmth greater. So, let’s get proper into it!

What Is Auxiliary Heat and How Does It Work?

It is essential to realize the different elements of a warmth pump and how they operate to discover about auxiliary heat. But first, let’s define auxiliary heat on a heat pump.

Warmth pumps use a mixture of electrical and mechanical implies to transfer warmth from one particular location to another. Normally, they are used in properties to offer heating or cooling.

A heat pump will work on its backup method if you use it in a area with no heat. This is called auxiliary heat. Auxiliary warmth gives supplemental heating power when the major method fails. It is also acknowledged as electric resistance heating.

The auxiliary warmth utilizes electrical energy and fuel to heat drinking water in a tank. You want to use as little auxiliary heat as achievable. Generally, auxiliary warmth is utilised when you have a cold-weather conditions program put in. This system utilizes an HVAC unit that blows air out of the area and heats the air before it goes back again into the room once more.

How a Heat Pump Works

A heat pump sucks in heat air from outside into the device. It is then cooled and pushed into your house by means of an evaporator coil. The evaporator coil is made of coils surrounded by refrigerant. It functions like a liquid when it will come in make contact with with the air.

This liquid refrigerant changes to vapor when it gets hotter than its boiling level. The vapor turns again into liquid when it reaches its boiling position once again. So, you have a continuous cycle of evaporation and condensation. The cycle qualified prospects to cooling and heating in your residence.

Primary Components of a Heat Pump

The Primary Pump

The main pump is the heart of a warmth pump. It is what helps make your technique a warmth pump.

The main pump has a motor and a supporter that draws air via the coils in the unit. The coils heat the air. These coils are produced of copper or other supplies.

The principal pump moves air via the warmth exchanger and transfers it from a single location to an additional. As this sort of, this component guarantees that the total system functions effectively.

white and gray heat pump
Image Credit: Carlos Lindner, Unsplash

The Evaporator

The evaporator is a vital part of a warmth pump. It’s the place the warmth is taken off from the refrigerant. Also, the evaporator is where the refrigerant arrives into contact with a gas or liquid, which absorbs its warmth.

The evaporator consists of a number of various elements. They perform with each other to take away warmth from a fluid—in this circumstance, refrigerant—and transfer it to an additional fluid.

The very first element is known as an evaporator main. It is composed of copper coils immersed in oil. The oil cools these coils as they take in heat from their environment. The next ingredient is a radiator. A radiator performs like an electric supporter. It blows air throughout the oil-filled coils to amazing them down even additional. Ultimately, an outer jacket surrounds the two parts. It helps prevent them from touching each other or other parts of your home’s heating method.

The Condenser

The condenser is the outermost component of your heat pump. It cools the heat from the refrigerant. It is manufactured of many steel fins and tubes that let it to shift with the other factors of the technique.

Typically, the fins are created of aluminum and are skinny. Even so, sometimes the tubes are produced of copper, which has a decrease thermal conductivity than aluminum but larger than air.

The refrigerant enters as high-temperature vapor and arrives out as a high-temperature liquid in the condenser. If the condenser is blocked from the outside, it can get ruined.

The Expansion and Compression Valve

The expansion and compression valves are located on the outer side of the warmth pump. These valves swap from one particular method to another. They also control how considerably refrigerant is unveiled or captured.

The growth valve converts the refrigerant into gasoline. Then, it travels by means of pipes to other parts of the method. When this has occurred, it will be compressed by the compressor, and then it’ll be sent back again into the system by means of yet another pipe.

The compression valve turns that gas back again into liquid sort. This way, it can be employed once more to execute its cooling perform.

What Are the Different Types of Heat Pumps?

There are a few main varieties of heat pumps. They include:

1. Air Source Heat Pumps

You can uncover air supply heat pumps in equally new and retrofit apps. So, you can get one particular that suits your place. These heat pumps are also inexpensive to install.

Two heat pumps outside the house
Image Credit: Nimur, Shutterstock

2. Water Source Heat Pumps

This one particular uses a shut-loop technique to transfer heat from an outside water supply or an indoor unit to provide heating and cooling for your residence. The outer water flows through tubes stuffed with refrigerant. Then, it is heated by coils within the device. A pump circulates this refrigerant through your house, creating sizzling drinking water and cold air as essential.

These warmth pumps use water as an power source. Normally, they supply reduced working fees in comparison to the electric powered types. Also, they have greater efficiency scores in contrast to air-source units due to the fact they use water as an power supply. These heat pumps require entry to h2o resources these kinds of as a lake or nicely, though, so they’re not frequent.

3. Ground Source Heat Pumps

These use a loop of drinking water heated by geothermal strength to change an electrical generator. They transform mechanical vitality into electric power.

Ground source heating programs provide far more effective heating than an electrical resistance heater. The only downside is that they are far more pricey than other central heating programs. Also, putting in floor supply heat pumps is far more expensive since you have to excavate to set up underground piping.

Where Are Heat Pumps Used?

Warmth pumps are an superb option for home owners who want to help save income on their heating charges. They are best in areas where temperatures really do not fall under the freezing stage.

Heat pumps are utilised in many places, from solitary-loved ones homes to big properties, this sort of as hospitals and faculties. They are also employed in supermarkets and industrial plants.

They are accessible in many dimensions and configurations, as a result getting used in different applications. Some give ample heat for little places like basements or garages. Other folks have ample heat for total houses or professional buildings.

You can retrofit present heating programs with heat pumps to improve efficiency and minimize operating costs.

  • Needs minimal maintenance
  • Mitigates carbon emissions
  • Safer compared to combustion-based systems
  • It’s entitled to the Domestic Renewable Heat Incentive Scheme.
  • Inexpensive to run than gas and oil boilers
  • Efficient energy to heat conversion rate
  • Long lifespan of between 20–25 years
  • Silent operation
  • Reduces the cost of your energy bill
  • Installing it is challenging
  • When the weather is cold, the heat pump can develop faults
  • High initial cost
  • Several fluids used in heat transfer are not sustainable

When Do You Need Auxiliary Heat?

You want to insert auxiliary heat to your residence at the proper time of the calendar year. This determination is dependent on different factors, which includes whether you live in an area where your house can take care of the further heat without any problem or if it has a history of higher temperatures.

Possibly way, there are numerous situations when it is really worth introducing auxiliary heating in your property as observed beneath.

1. The Outside Temperature Is Below Freezing

Auxiliary warmth is crucial when the out of doors temperature is under freezing. It’s also vital if you stay in a cold local climate and do not have a well-insulated house. If your residence has a good deal of insulation, you don’t want auxiliary warmth.

heat pump beside barbers lamp
Image Credit: Mak, Unsplash

2. Your Heat Pump Is in Defrost Mode

Your heat pump is functioning to maintain you warm throughout the coldest months of the year. But if it’s in defrost method, it is not making ample warmth to hold you cozy. The consequence is a lessen in indoor temperature.

The auxiliary heat will change on if your heat pump is in defrost method. It’ll stay switched on till the outside temperatures heat up or your house attains the sought after temperature.

So, how do you know your warmth pump is in defrost mode? Properly, right here are many symptoms to search out for:

  • The outdoor unit’s fan isn’t operating.
  • If you can see water or steam coming out of your outdoor unit
  • If there’s flickering light on the unit. In some models, it can indicate that it’s in defrost mode
  • Fan noise when changing from heating to cooling or vice versa
  • An increase in your electricity bill over time

3. When Increasing the Temperature by 3 Degrees or More

Auxiliary heat turns on when you add three levels or much more to the inner temperature. It may possibly consider time prior to your warmth pump raises the temperature indoors. Your warmth pump employs auxiliary warmth to make confident this requires location.

Heat pump on a residential home
Image Credit: Palatinate Stock, Shutterstock

How Do You Prevent Auxiliary Heat From Switching on?

The most widespread explanation a heat pump turns on auxiliary warmth is an mistake in the temperature sensor. The temperature sensor is inside the outdoor unit. It actions the outdoor air temperature.

The sensor sends a sign to the indoor unit to flip on auxiliary warmth if it is also cold. You cannot swap off auxiliary warmth manually. Even so, there are many approaches you can stop it from turning on. They consist of:

  • Add Insulation to your House – You can add insulation to your house in many ways. These include spray foam, cellulose, and other types. The most effective way is to install a continuous barrier around your home. It makes it much more difficult for heat to escape through the structure from inside to outside. So, the heat pump will not work hard.
  • Let the Sun Warm Rooms if Possible – If you can, allow the Sun to spread heat in your house. This way, you don’t have to rely on auxiliary heat to keep your home warm.
  • Close Doors to Rooms That Aren’t in Use – Another crucial tip to prevent heat pumps from turning on auxiliary heat is to close doors to rooms that are not in use. It will reduce the pressure difference between the room and its surroundings by keeping out any cool air that may be entering from outside.
  • Maintain Your System – You need to maintain your heat pump well to prevent it from turning on auxiliary heat. Make sure you are getting the proper maintenance done regularly. Clean the heat pump’s filters every 30 days. Also, let an expert inspect it before winter sets in. Doing so will reduce how often auxiliary heat switches on. This way, you can get the most out of this system.


1. How long should auxiliary heat run?

The heat pump will provide auxiliary warmth when the temperature of the inside falls below a established stage. It’s controlled by an indoor or out of doors temperature sensor and a thermostat. The actual time that auxiliary warmth will be on will vary based on the product, but it must be 30 minutes daily for a normal residence.

The quantity of time that the unit will run differs from model to design and from region to region. So, check with your regional seller or services service provider for more information about how long your device will operate.

2. When is auxiliary heat not needed?

You really do not require auxiliary warmth if the outdoors temperature is 40°F or greater. If auxiliary heat turns on at this temperature, your heating and cooling system may be getting a dilemma. So, it’s ideal to have it checked by an HVAC repair expert ahead of the issue persists.

3. Does auxiliary heat on a heat pump cost you more on energy bills?

If you include auxiliary heating to your system, it will cost far more vitality than employing the heat pump on your own. There’s a lot more electrical demand from customers from further parts this kind of as blowers and followers. So, auxiliary warmth is 50% much more high priced in contrast to conventional heat. The power used depends on how significantly auxiliary heating is essential for the technique to function well.

4. What is the difference between auxiliary heat and emergency heat?

There’s one major difference in between these two. Auxiliary warmth is a secondary resource of heat that switches on immediately. On the other hand, unexpected emergency heat is when you switch on the secondary heat source. These two heat varieties are equivalent but are labeled otherwise.

Auxiliary warmth maintains a cozy temperature in the place or residence although the major heat supply is off or has problems. Normally, it is activated by thermostats and turns on routinely when the temperature falls beneath a specified level.


A heat pump is an excellent way to lessen energy fees and make your house friendlier. There are several instances that can make auxiliary warmth on your heat pump flip on. Auxiliary heat is an additional supply of heat that turns on when the heat pump requirements to expel far more heat than it can generate. It is useful in cold temperature when there is a higher demand for heating.

While auxiliary heat can be a handy characteristic, it’s crucial to recognize what this purpose does. In the finish, it may possibly not be value it for some home owners as it may possibly conclude up employing far more vitality. We hope this report has answered any lingering inquiries you experienced on auxiliary heat on a heat pump.



Highlighted Picture Credit: David Papazian, Shutterstock