At Energimizer, we are experts in renewable and energy-efficient solutions for corporate and end clients alike. Alongside CHP smartblock motors and ESPE products, gaining an understanding of heat pumps and their role in sustainable HVAC systems allows you to make the best choice for your setting. In this guide, we’ll cover everything you need to know about these pumps in 2021.

What Are Heat Pumps?

Within the renewable HVAC industry, the term ‘heat pumps’ discusses a range of technologies that transfers thermal energy from the outside and uses it to circulate the heating and hot water systems within a property. Modern-day options are fitted with a reversing valve that quickly changes the flow of the refrigerant used. This means it can both heat or cool a room, transferring energy as needed from the air. Unlike furnaces, heat pumps do not independently generate heat – they simply move it from another location. So, when it comes to choosing one for your home or business, you need to take into account several factors such as your regional climate and the capacity of the building in question.

How Do They Work?

There are two key types of heat pumps – air source heat pumps and ground-source heat pumps.

Air Source Heat Pumps

In simple terms, an air source heat pump works similarly to a fridge but in the opposite direction. So, the air outside a property blows over refrigerant-filled tubes which causes them to heat up and convert the liquid refrigerant into a gas. This then travels into a compressor, which increases both the pressure and the heat in turn. Once the gases are at the right temperature, they move into a heat exchanger. The cold air or water around this exchanger then heats up and it is this that circulates your property, supplying heat and hot water as needed.

Ground Source Heat Pumps

Also known as a geothermal heat pump, ground source pumps move heat from the ground instead of the air. This allows you to take advantage of continual heat during different seasons and makes you somewhat less dependent on subtle weather changes. Using pipes bruised underground, heat is absorbed into the refrigerant within a ground loop. Again, this passes into a compressor where the temperature increases and can be used to heat your building. Because they use natural heat, they are considered a renewable energy source and have a reduced impact on the environment too.

Which One to Choose?

The right choice between air and ground source pumps will be entirely dependent on each individual property. Considerations need to be made about capacity, cost and installation requirements.


While the technologies used in both heat pumps are similar, the costs differ largely due to installation. Ground source heat pumps require excavation underneath your property to make way for the ground loop. This can mean that having one installed could cost up to £20,000 in some properties. However, because of the way in which they absorb energy from the ground, they are generally considered more efficient and have a greater impact on reducing your energy bills over time.


Air source heat pumps require the external temperature to be higher than that of the refrigerant to kick-start the process. In geographical locations where temperatures plummet and fluctuate significantly, this can make it harder to get consistent heating power. Ground source pumps, on the other hand, are more efficient due to the fact that the water in the soil is better able to hold heat when compared to air. Equally, most people are more reliant on their heating systems during the colder months – presenting an issue with air-source pumps too.


Weighing up the disruption that installing a heat pump will cause can also be an effective way of deciding the right option for you. Ground source pumps need some degree of excavation- especially if you’re working with a larger property. With two ways to install these pumps (horizontally and vertically), you may also need to factor in the costs and practicality of hiring specialist machinery. The installation will likely take a number of weeks however, there will be no visual change to the outside look of your property. Air source heat pumps are similar to air conditioning units in their appearance. Again, the larger your demands, the larger the heat pump will need to be. They can be installed and running within a few days but can generate some level of noise and may need planning permission in some locations.

Are They Energy-Efficient?

Both air source and ground source heat pumps require some degree of electricity to run. However, as they make use of waste heat that is already available – both in the surrounding air and in the ground below – they are a highly efficient method of heating a property. It is worth noting that their efficiency at heating relied on a number of factors, including how hard they need to work in order to maintain a consistent temperature. Having a heat pump that is sized appropriately for your property and tailored features, such as larger radiators and underfloor heating, you’re likely to see a higher ROI and saving on energy bills over time. Equally, factors such as the type of ground underneath a property can impact their efficiency (clay-based grounds reduce thermal conductivity, thereby reducing efficiency).

When sized and installed following a survey and support from a speciality company, heat pumps have been shown to help reduce heating costs by 2/3s in comparison to electric heating alternatives.

Energimizer is an industry expert in renewable, sustainable and energy-efficient heating systems to support both corporate and end clients throughout the decision process. We have a highly experienced and professional team on hand to help guide you at all times. For more information about heat pumps, CHP systems or ESPE products, get in contact here today.