Heat pumps are becoming increasingly accessible, alongside a whole range of low-carbon heating systems. With the benefits of reducing our carbon footprints and also our energy bills, heat pumps are set to become as familiar in domestic homes as traditional gas boilers.

So what are heat pumps, what different types are available, and what are their biggest benefits? At Ideal Heating, we’ve collected all of the information you need to know about heat pumps in one place, answering frequently asked questions about these exciting home heating solutions. 

What Is a Heat Pump?

Heat pumps provide an alternative way of heating our homes, offering us the chance to cut down on our carbon footprint and also reduce our energy bills. The two most widely used types of heat pump are air-source (or ‘air-to-water’) and ground-source (or ‘geothermal’) heat pumps. 

What all heat pumps have in common is that they extract heat from natural sources, such as the air or the ground, which they then use to provide hot water and central heating to our homes. 

Unlike boilers, heat pumps are most often located outside our homes, with many fixed on an external wall or placed securely on the ground outside a property. 

How Does a Heat Pump Work?

Heat pumps absorb warmth from sources of heat including the air, ground and bodies of water. They do this by transferring the heat to a liquid (called a ‘refrigerant’), which circulates through a looped system of pipes. Heat pump systems then use a compressor to heat this fluid up by increasing its pressure. 

When the fluid reaches the correct temperature, it’s then able to provide the heating we need in our homes, for our radiators, hot water and other domestic heating like underfloor heating. Another useful feature of heat pumps is that they can act as air conditioners by reversing this process, extracting the heat from the air in your home and moving it outdoors.

Different types of heat pump work in slightly different ways, as we will explain below.

What Is an Air-Source Heat Pump System?

An air-source heat pump absorbs the warmth in the air around our homes to heat our properties and provide us with hot water. They are most often located outdoors and are very effective at providing domestic heating, even when the weather outside is cloudy and dull.

How Does an Air-Source Heat Pump System Work?

An air-source heat pump works by absorbing heat from the air into a fluid (called a refrigerant) that travels through a looped system of pipes. This process increases the temperature of the liquid until it transforms into a gas (vapourises). 

This gas moves through the system towards a compressor, which increases its temperature even further until it’s warm enough to provide us with central heating and hot water. Any leftover heat can be stored in a hot water cylinder. 

As the gas heats your home’s central heating system, it starts to cool and transforms back to a liquid (condenses). This liquid is pumped back outside into the looped pipe system, which restarts the process as the liquid begins to absorb more heat from the air.

How Heat Pumps Work

How Efficient are Heat Pumps?

Heat pumps are very efficient central heating solutions that use naturally occurring heat to provide us with hot water and domestic heating. An air-source heat pump can produce as much as four units of heat for every unit of electricity it uses. 

Air-source heat pumps will not be able to perform to their full efficiency if the temperature outside is cooler, but even then they’ll still produce more units of heat than the units of electricity they use. 

Because they’re so good at increasing the temperature of the heat they absorb, they can still provide the warmth to heat our homes in temperatures as low as -15 °C.

Ground-source heat pumps are often more efficient than air-source heat pumps but they are also more costly and complicated to install, especially as this process requires you to bury pipes in your garden. 

What are the Benefits and Advantages of Heat Pumps?

The biggest advantage of installing a heat pump is that it’s much more energy efficient than traditional central heating systems, even modern condensing gas boilers. This means they will have a positive impact on both your carbon footprint and your energy bills.

They are easy to install, although fitting a ground-source heat pump takes longer than an air-source heat pump because it involves burying pipework in the ground. Installing a heat pump may also make you eligible to claim back money as part of the UK government’s Domestic Renewable Heat Incentive (RHI)

What Is a Ground-Source Heat Pump System?

A ground-source heat pump is also known as a geothermal heat pump. It works by absorbing natural heat from the ground into a ‘ground loop’ of buried pipes, before transferring that energy to provide our homes with hot water and central heating. 

How Does a Ground-Source Heat Pump System Work?

A ground-source heat pump absorbs heat from the ground into a mixture of cold water and antifreeze, which moves through a looped system of underground pipes. The temperature of the liquid increases as it moves through the system, and the heat produced is used for our homes’ central heating and hot water.

Are There Any Other Types of Heat Pump Systems?

A third and less common type of heat pump system is the water-source heat pump. These heat pumps work similarly to ground and air-sources systems, with the main difference being that they extract heat from bodies of water to power domestic heating and hot water. 

Water-source heat pump systems can be used for properties that have a nearby lake or river, or even an underground aquifer that holds water. Because they need a large volume of water to generate the heat needed to power a system effectively, they are much more rarely used in the UK than air-source heat pump systems. 

Do Heat Pumps Freeze Up in the Winter?

Heat pumps are designed to run efficiently all year round and are well equipped to run in cold temperatures. Some heat pumps can continue working in outside temperatures of -20°C and will run defrosting cycles in very cold weather to make sure they continue working properly. 

Which Type of Heat Pump Would Be Best for My Home?

Choosing the right heat pump depends on how much space is available in your garden. An air-source heat pump is easier to install and simply needs space outside your house for an outdoor unit, either mounted on a wall or positioned safely on the ground.

Domestic Heat Pump Working

A ground-source heat pump requires piping to be buried in the earth and you’ll need enough space to accommodate it, which will ultimately depend on the size of your garden. Ground-source heat pumps can be more efficient, which means they could be a better choice for larger homes.

How Often Will a Heat Pump Need Replacing?

The average lifespan of a heat pump is roughly 15 years, which is around the same length of time as a modern gas boiler. Newer heat pump models may actually continue to work efficiently for even longer and could possibly last up to 25 years.

By keeping your heat pump well maintained you will help it work more efficiently and last longer, so it’s always worth taking good care of it, which can include annual checks from qualified engineers.

Do Heat Pumps Need Servicing?

It’s recommended that you have your heat pump serviced at least once a year by a heating engineer to make sure it’s running efficiently. It will also mean the system is checked for problems, so any issues can be discovered and fixed quickly before they get worse.

Finding problems with your heat pump early can help prevent them from causing larger issues that could be more expensive to fix further down the line.

Do Heat Pumps Use Radiators?

Heat pumps will most likely work with the radiators you currently have in your home, and a heat pump engineer will be able to help you understand whether any changes are necessary. Heat pumps also work very efficiently with underfloor heating, which could be another option for your property.

How Do I Clean a Heat Pump Unit?

If the outside of your heat pump unit needs cleaning, turn off the power to the appliance before wiping it down with a non-abrasive cloth and warm water. If you notice a build up of leaves or debris around the outdoor unit, you can carefully brush them away. 

If you think there’s a technical problem with your heat pump unit you should never try to clean it out or fix it yourself. By having your heat pump serviced at least once annually by a qualified engineer, you can make sure that any potential issues are spotted and resolved quickly.

What Size (kW) Heat Pump Do I Need for My Home?

The size of the heat pump you’ll need for your property depends on factors including how large your home is and the size of its radiators. If the heat pump is too small it won’t provide the amount of heat you need, while if it’s too large that could also cause issues. 

An oversized heat pump can ‘short cycle’, which means it will keep switching on and off in a short space of time and use far more energy than it should. Contact a qualified engineer or installer to help you find out which size heat pump is the best option for your property.

Does a Heat Pump Need a Flue?

Heat pumps don’t need a flue because they don’t burn gas to create heat like boilers do, which is the process that creates waste gases. Heat pumps work very differently from gas boilers, using naturally occurring heat energy to provide our central heating, meaning a flue is not required.

Do Heat Pumps Still Work in Low Temperatures?

Heat pumps are often located outdoors and are very effective at absorbing heat from the ground or the air, even when the weather outside is cloudy and dull. In fact, air-source heat pumps can absorb enough warmth to heat our homes in temperatures as low as -20 °C.

Heat Pumps In Cold Weather

Are Heat Pumps Able to Heat and Cool Properties?

Heat pumps actually work very similarly to air conditioning units, but in reverse. Instead of absorbing heat from the air to cool a space down, heat pumps usually absorb warmth from the ground or earth, then use this absorbed heat to warm up our homes.

In the summer months, many heat pumps can be programmed to cool your home. They are able to do this by reversing their usual process, meaning they absorb and transfer heat away from rooms in our homes that are uncomfortably warm.

Are Air-Source Heat Pumps Classed as Renewable Energy Sources?

The experts at the Energy Saving Trust say air-source heat pumps are “an energy efficient method of heating your home” as they use renewable heat from all around us. The amount of heat that they provide is greater than the amount of electricity that is used to power them. 

Heat pumps do use electricity as part of the process of providing us with domestic heating and hot water, but you can make them even more environmentally friendly by using an energy provider that offers 100% renewable power.

Can You Install a Heat Pump in an Existing Home?

Heat pumps are likely to be used in many new build homes going forward, with new homes built after 2025 not using gas boilers — this is due to legislation set out by the UK government to help the country reach its target of lowering CO2 emissions.

However, heat pumps can provide an energy-efficient heating option for existing homes too. Get in touch with a qualified heat pump installer to find out whether a heat pump would be the right choice for your home.

How Do You Install a Heat Pump?

A heat pump should always be installed by a professionally qualified engineer. When considering a heat pump, it’s important to remember that air-source heat pumps are located outside, so you will need to make sure you have a suitable place for it to be kept.

A ground-source heat pump is more complicated to install than an air-source model, as it involves pipes being buried underground to extract heat from the earth. Contact a qualified heat pump installer to learn more about what the process will involve.

Do Heat Pumps Use Electricity?

Heat pumps do use some electricity as part of the process of creating heat for hot water and domestic heating. However, they can provide far more heat per unit of electricity than traditional appliances such as boilers, as they use heat from natural sources like the air.

How Much Do Heat Pumps Cost?

According to the Energy Saving Trust, the cost of installing a typical heat pump system will be between £9,000 – £11,000. How much it will cost to run depends on how large your property is, how well it’s insulated and what room temperature you want it to provide.

Heat pumps are much more energy efficient than gas boilers, so it’s likely that switching to this method of central heating will actually save you money on your utility bills in the long run.

How Long Will Installing a Heat Pump Take?

The amount of time it takes to install an air-source heat pump will generally be between one and three days, depending on factors including the size of the property. Ground-source heat pumps may take longer to install as they will need to have pipes buried in the ground.

Are There Any Grants Available for Heat Pumps?

If you live in England, Scotland or Wales, you may be eligible for money to help pay for renewable heating costs in your home. The Domestic Renewable Heat Incentive (RHI) allows you to claim for some heat pumps and is available for homeowners and private or social landlords.