Heat Pumps: An In-depth Guide | Types, Benefits, Cost, FAQs

Heat Pumps UK

Considering installing a heat pump on your property? Check out this guide to learn everything you need to know about heat pumps and their benefits.

Are you interested in installing a heat pump for your property? A heat pump can be a great way to heat the building without spending too much on energy bills. It’s very efficient, and the installation process usually doesn’t take a long time.

In this guide, we’ll give you an in-depth overview of how heat pumps work, their benefits, and what type you should consider installing.

What Is a Heat Pump and How Does It Work?

A heat pump is a device used to transfer thermal energy from one place to the other, typically from the outdoors to an enclosed space.

Heat pumps use electric energy to compress the gas, also called the refrigerant. When the gas is compressed and the pressure increases, the temperature also rises.

The heat exchanger installed inside your home draws heat from the gas, and its temperature starts to drop as it’s allowed to expand. Such a drop in temperature causes the refrigerant to draw heat from outside air, starting the cycle all over again.

Types of Heat Pumps

There are multiple types of heat pumps that operate differently, which include:

Air Source Heat Pumps (ASHPs)

An Air Source Heat Pump (ASHP) is a type of heat pump that uses air as a source of heat energy. The cold refrigerant moves from the evaporator on the outside of your house and draws heat from the air that passes through the heat exchanger with fans.

Air Source Heat Pump Installers

Even when the air is cool, it will suffice for the ASHP to operate due to the large volumes that blow across the heat exchanger.

Ground Source Heat Pumps (GSHPs)

A Ground Source Heat Pump (GSHP) absorbs heat from water that runs in the underground pipework. The water is heated with a heat exchanger installed inside the property.

Ground Source Heat Pump

When the antifreeze and water mixture passes across the heat exchanger, heat is transferred to the refrigerant before it reaches the compressor.

Other Heat Pump Types

While air source and ground source heat pumps are the most commonly used heat pumps in the UK, there are other types that are worth mentioning.

Inverter Heat Pumps work on demand based on the conditions. With an inverter heat pump, you can save up to 30% on running costs.

Another advantage is that you can leave it on 24/7 because inverter heat pumps are actually designed to be left on all the time. It’ll only work when the prevailing conditions require it.

Another less common type is Hybrid Air Pumps. A hybrid air pump operates like an air source heat pump in the summer and a conventional boiler in winter. You can set it to automatically switch to boiler mode when the temperature drops below 7°C.

Benefits of Installing a Heat Pump

Here are some of the perks of installing a heat pump on your property:

Low Carbon Footprint

Unlike other heating systems that rely on fuel, heat pumps are 100% electric, which can drastically contribute to a lower carbon footprint. You get to enjoy a warmer home without negatively affecting the environment.

Provides Heating and Cooling

Heat pumps aren’t just for heating. While heat pumps do a great job at making your home warmer and more comfortable, they can work in reverse, and instead of absorbing heat from the outside to the inside for heating, it transfers heat from the inside to the outside, making the indoor spaces cooler.

Easy to Maintain

Heat pumps are quite easy to maintain. Given that the system was properly installed, you’ll only need a technician’s visit every once in a while for routine maintenance.

Heat pump users rarely experience any problems with their systems, but even if it happens, your installer can probably get it fixed on the same day.

Minimal Energy Costs

Heat pumps are much more efficient than conventional boilers. They produce a lot of heat compared to their consumption.

Can Be Installed in Existing Homes

One of the biggest advantages of heat pumps is that they can be easily installed in existing homes. Unlike other types of systems that require installation during the construction process, heat pumps can be installed in pre-established homes.

How Efficient Are Heat Pumps?

Heat pumps are very efficient, but fluctuations in temperature will affect your heat pump’s efficiency. The colder the air out there, the more work the heat pump has to do.

Air source heat pumps work more efficiently when the outdoor temperature is above the freezing point. When it’s too cold outside, the heat pump will consume more electricity.

As for ground source heat pumps, things get better. The water in the underground pipes used to operate the heat pump is less affected by the temperature, so you should expect a GSHP to operate more efficiently than an ASHP throughout the year.

If it doesn’t get too cold in your city, an ASHP and a GSHP will work equally efficiently.

How Much Does a Heat Pump Cost?

The costs of a heat pump depend on its type and model. There are 3 numbers to consider when determining the cost of a heat pump, which are:

  • The cost of the heat pump
  • Installation costs
  • Running costs

Air source heat pumps cost £10,000 on average, while ground source heat pumps cost £15,000.

However, the running costs of a ground source heat pump typically don’t exceed £500 for a four-bedroom house, compared to £700 for an air source heat pump.

Installing a GSHP also costs more than installing an ASHP in most cases due to the additional building work required.

How Is the Performance of a Heat Pump Calculated?

The performance of heat pumps is quantified in the form of a Coefficient of Performance (COP).

Generally speaking, ASHPs have a COP of about 3.2, meaning that every 1kW of electricity produces 3.2kW heat. On the other hand, GSHPs have a COP of 4.

To maximise the performance of your heat pump, optimise the controls so that you get the best possible heating level for your house.

Manufacturers include a data sheet for every heat pump they release that shows how the COP is calculated. It’s worth mentioning that the COP is measured at one point, so it’s expected that the efficiency will be different in real-life situations due to temperature fluctuations.

That’s why heat pump installers calculate the Seasonal Coefficient of Performance (SCOP), a metric calculated on-site based on real-world data.

Depending on the heat pump system design, the size of the radiators, and the average temperature in your location, the installer will calculate the SCOP to give you an idea of the system’s efficiency. The installer will also hand over these calculations before the installation process.

How to Calculate the Heat Pump Size You Need

Air source and ground source heat pumps have output ratings that make it easier for you to determine the ideal size for your home. There are no universal heat pumps that will work as effectively in homes of varying sizes.

The bigger your home is, the bigger the size of the heat pump you’ll need. However, the process is a little bit more complex than simply choosing a heat pump based on your house’s size. There are lots of other factors that you should take into consideration, which include:

  • Heat loss rate
  • The presence of underfloor heating
  • Required indoor temperature
  • Size of radiators
  • Level of insulation
  • Seasonal outdoor temperatures in your region

To avoid installing an improper system for your home, it’d be best to contact a professional installer. Professional installers conduct accurate calculations to ensure optimal heat pump size and design.

Nevertheless, if you want to get a quick idea of what size heat pump you’ll need, take a look at the table below:

However, we’d take these numbers with a pinch of salt because, as we’ve mentioned, properly sizing a heat pump requires a professional inspection.

Heat Pumps FAQs

In most cases, you don’t need permission to install a heat pump in the UK. The installation of a heat pump falls under the umbrella of ‘permitted developments’, so you won’t likely need a permit to install such a system on your property.

However, under certain criteria, permission might be required. To be on the safe side, contact your local planning department for details on the required permissions if any. Your installer would also be familiar with permission requirements in your area, so you can contact them too.

It’s also worth noting that you must inform your local district network operator (DNO) of your intention to install a heat pump. Again, getting in touch with your installer would be beneficial here as they’d probably be familiar with the form-filling procedures.

It depends on your needs and budget. Air source heat pumps are economical and provide a great performance. They also produce minimal noise.

On the flip side, ground source heat pumps are somewhat costly to install, but their running costs are lower than air source heat pumps. They also provide better performance.

If you have a conventional oil-based heating system in your house, switching to a heat pump would definitely have a good impact on your energy bills.

Boilers might cost you less to run, but you can make your heat pump more efficient by installing an underfloor heating system to complement it. This way, your energy bills will be much less than what you’d pay with a boiler.

Generally, the running costs of a heat pump in comparison to your current system will depend on the type of fuel you’re replacing and its cost, the heating system’s design, your electricity tariff, and the climate in your location.

A heat pump that’s designed to optimally match the needs of the property should last for 20-30 years with proper care and maintenance.

The installation also plays a big role here, especially for GSHPs. Proper installation that takes into consideration the ground conditions will contribute to the longevity of your heat pump.

Heat pumps become least effective when the outdoor temperature is anywhere between -4°C and 4.5°C. To get the most out of your heat pump, only use it when the outdoor temperature crosses 4.5°C.

Even if the heat pump makes the place a bit warmer in temperatures below 4.5°C, it’ll work at a much faster rate than normal, which compromises its efficiency.

As a general rule of thumb, it’s better to undersize a heat pump than to oversize it. In the worst-case scenario, an undersized heat pump will take a bit longer to make the place warm. On the other hand, an oversized heat pump will not only consume more energy but also produce more noise.

Not to mention, oversized heat pumps will keep turning on and off frequently, which further affects efficiency. However, make sure that you don’t exaggerate it when it comes to under-sizing a heat pump. A heat pump that’s too small for your house will be as useless as none.

Final Words

If you want to install an air source or ground source heat pump in your home, choosing the right heat pump installer is crucial

Some heat pump installers give you a free consultation when it comes to the best type of heat pump to install on your property.

Not all homes are the same; each will require a different heat pump design based on its size, location, and other variables. A reputable installer will install a heat pump system that delivers a satisfactory performance while maintaining efficiency.

Before the installation process starts, the installer will provide you with detailed mechanical and electrical drawings, as well as all the necessary calculations for transparency.

The duration of the installation process varies from one home to another, but when the installer comes for an on-site inspection, they’ll provide the estimated turnaround time needed to complete the installation.

In many cases, they’ll be able to install the system in one day if everything goes smoothly.

On top of that, it’s important that you choose an installer that works with the MCS to make sure that you get the required support documentation needed for RHI incentives applications.

On a final note, remember that heat pumps are safe for the environment, so you’ll be directly contributing to a greener Earth when you switch to a heat pump system.