Finding cost and energy efficient alternatives to the resources we typically rely on for warmth has become a heated discussion in the UK. However, heat pumps have been hugely successful in the EU and the US, and now the technology appears to be picking up momentum in the UK, too.

Indeed, heat pumps are earmarked to be the future of heating all homes across Britain in just a handful of years – but what actually is a heat pump and how does it work?


What is the purpose of a heat pump?

The principal purpose of a heat pump is to transfer energy from one source to another and to provide heat in our homes through our radiators, water tanks and underfloor heating systems.

Heat pumps provide a renewable source of energy that is far kinder to the environment than a traditional boiler while also keeping our homes at an optimum temperature.


What is needed to keep heat pumps running?

As heat pumps become increasingly popular on a global perspective, it’s important to know that heat pumps require maintenance. A part of that maintenance is ensuring heat pump lubricant isn’t lacking in application. Heat pumps for heating and hot water supply mainly use CO2 and HFO lubricants which enable high performance as we move towards natural and synthetic Low Global Warming Potential lubricants.


How does a heat pump work?

How a heat pump functions largely depends on its source. For example, a ground source heat pump collects heat from the earth using a collection pipe that is buried underground while a water source pump generates thermal energy from lakes, rivers and the sea. Likewise, an air source heat pump collects heat from the air outside.

A heat pump works in a “reverse refrigeration cycle” as follows :

  1. The source of heat – air outside or warmth from the ground – is blown or pumped over the heat exchange surface of the exterior part of the heat pump.
  2. This heat (although cold in comparison to a centrally heated home) is warm enough to cause the refrigerant liquid to evaporate and turn into a gas.
  3. This gas then moves through a compressor, which increases the pressure and so causes its temperature to rise.
  4. The gas (now heated) is passed over the internal heat exchange surface. This heat can then be either blown around the interior or transferred into a central heating or hot water system.
  5. The gas falls in temperature as the heat is transferred into the home and it subsequently returns to a liquid state.
  6. The cycle of reverse refrigeration repeats until your home or business reaches the required temperature setting on your thermostat.

Heat pumps also require electricity for this process to work and, for that reason, cannot be considered entirely net carbon.


What are the different types of heat pumps?

There are many different types of heat pumps, including:

  • Geothermal heat pump
  • Exhaust air heat pump
  • Solar assisted heat pump
  • Water source heat pump
  • Hybrid heat pump

However, there are two main types in the UK: ground source and air source.

Although heat pumps are more efficient than boilers, ground source or geothermal heat pumps are even more efficient. That’s because the ground provides a constant source of heat while air source heat pumps are at the mercy of the air outside which, especially in the UK, can drastically vary in temperature from day-to-day.

Still, air source pumps are the most common as they’re easier and cheaper to install. They don’t need a complex web of pipework deep underground to function – they simply need access to air outside to transfer it through. They usually look like air conditioner units, and actually can be reversed to provide cool air when needed, too.


Application purposes of heat pumps

The application purposes of heat pumps can also vary. They can be used for:

  • Heating and cooling of buildings and vehicles
  • Water heating – to heat or preheat water like swimming pools
  • Industrial heating – to lower waste and reduce greenhouse gas emissions
  • District heating – to attend to larger zones where multiple buildings can be connected


How is a heat pump different from a traditional boiler system?

The key difference to remember between a heat pump and a traditional boiler system is how they deliver heat.

While a boiler may be used intermittently and multiple times throughout the day to quickly heat up the home, a heat pump ensures a steady state of temperature that is comfortable all day long. Boilers may be faster at delivering warmth, but a heat pump ensures the property doesn’t drop to uncomfortably cold temperatures in the first place. Heat pumps are even efficient at providing warmth when temperatures drop below -15 C.

The next difference between the two is the cost to our wallets and the environment: boilers have higher operating costs, higher CO2 emissions and higher energy bills than homes which stay warm with a heat pump.


Is a heat pump beneficial?

Whether you will benefit from a heat pump all boils down to the existing insulation of your home. Your property will need to be well-insulated in order for the heat pump to function at its best, which may mean installing a cavity wall or double-glazed windows to trap the heat in, which is neither a quick or cheap fix.

Some homeowners do not like the noise, appearance and/or size of the heat pumps, while others simply prefer the quick rush of heat that a gas boiler can provide.

However, a heat pump is certainly beneficial when it comes to lowering energy bills and reducing your carbon footprint. When coupled with solar panels to generate electricity, your heat pump can even be deemed carbon-neutral.


See our Heat Pump lubricants here:




Written by:

Robert Chevasco, Sales Manager, Shrieve Products International Ltd.