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Best Air Source Heat Pumps


In a bid to lower their heating costs and carbon emissions, many UK households are considering installing an air source heat pump in place of their fossil fuel boiler. However, with several companies currently manufacturing air source heat pumps, homeowners are often faced with the dilemma of which air source heat pump model to install.

If you are currently in the same predicament, you need not worry anymore as this article has got you covered. In this guide, we discuss everything you need to know about air source heat pumps. We will also compare the cost, warranty, maximum power output, and minimum operating temperature of several of these machines to create a list of the best air source heat pumps in the market. And by the end of this read, we hope you will have sufficient information to make an informed decision on the best air source heat pump for your home.

What is an air source heat pump?

An air-source heat pump is a renewable heating solution that extracts heat from the air outside your property and uses it to heat your home and your hot water. Air source heat pumps are an efficient and eco-friendly alternative to fossil fuel boilers, reputed to lower your carbon footprint by 38%. In terms of efficiency, the air source heat pump is 3-4 times as efficient as a gas boiler, meaning it can generate up to 400% of the energy it consumes while in operation.

How do air source heat pumps work?

An air-source heat pump can be likened to a “reverse fridge” in that it operates using the same analogy as a refrigerator, only in reverse. Simply put, the air source heat pump draws heat from the outside air in your home, amplifies it, and sends it to the radiators or underfloor heating system in your home.

The operation process of an air source heat pump can be simplified into the following five steps:

  1. The pump draws air from outside your property and passes it over a refrigerant liquid maintained at a low temperature. As the air is blown over it, the refrigerant liquid extracts heat from it.
  2. The pump uses electricity to compress the liquid refrigerant to increase its temperatures, and in the process, vaporizes it.
  3. The compressed refrigerant vapour is passed over a heat exchanger in contact with the cold water in the wet central heating system. As the heat is extracted from the refrigerant vapour and transferred to the cold water, it condenses to liquid.
  4. The heated water is sent to the radiators or underfloor heating system in the property, while the remainder can be stored in a hot water cylinder for later use.
  5. Alternatively, the compressed refrigerant vapour transfers its heat to the surrounding air, effectively warming it. The warm air is then circulated using fans.

Types of air source heat pumps

Air source heat pumps can be divided into two main types: air-to-air and air-to-water.

  1. Air-to-air heat pumps: These are air source heat pumps designed to provide space heating. They draw heat energy from the outside air and circulate it in your home using fans. In the summer, an air-to-air heat pump operates in reverse and is used as an air-conditioning unit. However, as this system does not generate hot water, it isn’t eligible for the government’s Renewable Heating Incentive.
  2. Air-to-water heat pumps: These heat pumps extract heat from the outside air in your home and circulate it around your home using your wet central heating system. However, as these systems operate at a lower temperature compared to traditional boilers, they are usually installed with large low-flow radiators and underfloor heating systems. Air-to-water air source heat pumps are eligible for the government’s Renewable Heat Incentive.

Air-to-water heat pumps are further subdivided into two categories: monobloc and split heat pumps. Monobloc heat pumps refer to those air source heating systems with all their components besides the hot water cylinder installed in one compact unit outside your home. On the other hand, as the name suggests, a split heat pump system is split into two units, one external unit and one internal unit.

Best air source heat pumps

With the popularity of air source heat pumps continuing to rise each passing day, more companies are moving into the market, meaning consumers aren’t short of options. However, no two air source heat pump models are the same, and what works for your neighbour may not work for you. As such, we have prepared this detailed list of the best air source heat pumps to save you the hassle of exploring the market blindly.

Besides the overall best list, we have also ranked the best air source heat pumps in terms of categories to help you identify the best model for your home.

  1. Mitsubishi Electric Ecodan QUHZ Monobloc

Mitsubishi Electric has been manufacturing electric and electronic devices such as air conditioning units since 1921. The company is at the forefront of renewable energy solutions and currently manufactures ground, and air source heat pumps in Livingston.

The most popular of their air source heat pumps is the Ecodan QUHZ Monobloc, a self-contained air-to-water heat pump unit. It consists of an outdoor unit connected to electric and water supply units and an indoor hot water cylinder or thermal store. Ecodan units have one of the lowest noise outputs amongst air source heat pumps and can operate effectively even at icy external temperatures of -25 degrees Celsius.

Ecodan Monobloc units have an ErP rating of A++, meaning they are highly efficient. Additionally, they incorporate smart tech and can be controlled via a wireless controller or a mobile application.

A Mitsubishi Ecodan heat pump costs between £2,000 and £5,000 before installation. With installation costs, the price can potentially reach £8,000.

  1. Nibe F2040

Nibe is a Swedish company that manufactures domestic heating products in several countries across Europe. And despite the company not being a household name in the UK heating industry, it has made a name for itself in the heat pump industry through the Nibe F2040.

The Nibe F2040 is the company’s most successful air source heat pump range and currently features an A+++ ErP efficiency rating. Their heat pump units are designed for easy installation and are fitted with an anti-vibration external water connection.

Technology-wise, the Nibe 2040 doesn’t slack off and comes with an Uplink App, which enables homeowners to monitor the performance of their heat pump unit at any time. The NIBE Uplink app provides quick overviews and operating status of the air source heat pump at any point in time.

Nibe air source heat pumps are expensive and cost between £6,000 and £8,500 before installation.

  1. Daikin Altherma 3

When it comes air innovative air conditioning units and climate control technology, Daikin is yet to meet an equal despite being in the business for the last 97 years. Being at the forefront of renewable heating solutions, the company has invested heavily in heat pumps to combat climate change.

The Daikin Altherma 3 is the company’s most successful air-to-water heat pump and can operate at temperatures as low as -25 degrees Celsius. This means that you won’t have to worry about a lack of heating even in the heart of winter. What makes the Altherma 3 stand out from the other air-to-water heat pumps is the R32 refrigerant in its system. The heat pump became the first one in the UK to incorporate this new refrigerant lauded to have the least environmental impact.

Daikin Altherma 3 heat pumps feature an overall season A++ ErP rating and can be installed with solar support in a hybrid heating system. The unit also features a simplistic design, with all its hydraulic components being easily accessible.

In terms of price, a Daikin Altherma 3 heat pump will cost you between £6,000 and £8,000 before factoring in the installation costs.

  1. Samsung EHS Monobloc

After years of research, Samsung, the South Korean tech giant, finally made its debut in the heat pump industry by launching a range of competitively priced, high-performance heat pumps. The company’s leading air source heat pump is the Samsung EHS Monobloc unit which costs around £6,000 before installation.

The heat pump unit is compact and lightweight and can even be suspended above the ground. Other prominent features of the model include a low operating temperature of -25 degrees Celsius, a low sound rating, and a high water temperature flow of 55 degrees Celsius.

  1. Viessmann Vitocal 200-A

As one of the leading boiler manufacturers in the UK market, it is no surprise that Viessmann would invest in heat pumps. After all, heat pumps are widely regarded as the heating solution of the future and are bound to replace fossil fuel boilers. Like most of the company’s products, the Viessmann Vitocal 200-A air source heat pump features a sleek, extremely modern design.

The heat pump model can attain a maximum flow rate temperature of 65 degrees Celsius for central heating and 40 degrees Celsius for domestic hot water. Moreover, the unit is designed to operate in reverse during the hot summer months, meaning you can use it for air conditioning during the warmer months.

Lastly, the Vitocal 200-A can integrate with both new and existing heating systems, making it ideal for a hybrid unit. The unit also features a user-friendly control unit with the option of remote control through the ViCare app and Vitoconnect.

  1. Grant Aerona3 R32

The Grant Aerona3 is the most successful third-generation air source heat pump released by Grant. These heat pump units are available in different output ratings, including 6, 10, 12, and 16kW models. Grant Aerona3 heat pumps use the more environmentally friendly R32 refrigerant and pride themselves in being the first monobloc air source heat pump in the UK to use this refrigerant.

  1. Vaillant aroTHERM

Vaillant is another prominent gas boiler manufacturer that has tried its hand at manufacturing air source heat pumps. The manufacturer’s aroTHERM air source heat pump has established itself as one of the market’s top air source heat pumps. Vaillant aroTHERM comes with an MCS accreditation and is Quiet Mark approved, thanks to its ultra-quiet operation. Another unique feature of this heat pump unit is the blue-fin coated evaporator designed to improve its performance and corrosion resistance.

  1. LG THERMA V R32

The LG THERMA V R32 is another heat pump model that uses the environmentally friendly R32 refrigerant. It features an A+++ ErP rating, which can be attributed to its unique Revolutionary Scroll Compressor. Other notable features of this heat pump unit include a low operating temperature of -25 degrees Celsius, intuitive controls and remote smartphone app, and a maximum hot water flow rate of 65 degrees Celsius.

  1. Hitachi Yutaki S802

Wrapping up the list of the best air source heat pumps is the Hitachi Yutaki S80 air-to-water heat pump. It is a unique high-temperature air source heat pump capable of delivering hot water at temperatures of 80 degrees Celsius. The heat pump’s high water temperature output is attributed to its secondary Cascade R134a Heat Pump Circuit. The heat pump also features an A+++ energy efficiency rating and can operate even in temperatures as low as -20 degrees Celsius.

Best air source heat pump for cold climates

If you live in a cold region, you should consider installing the Samsung EHS Monobloc or the LG THERMA V R32 heat pumps, which can operate even at low external temperatures of -25 degrees Celsius.

Best air source heat pump for efficiency

If you are after the most efficient heat pump in the UK market, you should purchase the Hitachi Yutaki M RASM-4VNE air source heat pump as it features a 500% efficiency.

Best air source heat pump for cost

The Grant Aerona3, priced at £5,394, is the best air source heat pump for those operating with a tight budget.

Best air source heat pump for maximum power

Vaillant’s flexo THERM 400v air source heat pump is the current holder of the longest air source heat pump warranty. The heat pump clocks an efficiency of 467% and has a full warranty of 7 years.

Best air source heat pump for swimming pools

The HydroPro ECO 12 air source heat pump is the ideal choice for those seeking a heating solution for their swimming pools. The heat pump comes with a 2-year warranty, a maximum power output of 12kW, and high efficiency of 480%.

Advantages of installing an air source heat pump

Air source heat pumps have several benefits, making them a popular heating solution in the UK heating industry. Some of the benefits you can reap by installing an air source heat pump in your property include:

  1. Reduced energy bills

As earlier mentioned, air-source heat pumps can unlock up to 400% efficiencies. This means you will be heating your home efficiently using less energy than when using a gas boiler. Less energy consumption translates to lower energy bills, and you can potentially save up to £215 off your annual energy bill.

  1. Lower carbon emissions

Air source heat pumps do not burn fossil fuel to generate heat, only requiring little electricity to extract heat from the surrounding air. This means the carbon emission from heating your home will only be restricted to that produced in generating the electricity. By installing an air source heat pump, you stand to lower your annual carbon emission by an average of 1771 kg.

  1. RHI payments

The UK government is advocating for the adoption of renewable heating solutions. And to achieve this, it is rewarding homeowners and businesses that have installed heating systems such as air-to-water heat pumps through the Renewable Heating Incentive (RHI). Through this scheme, the government will pay you a fixed rate for every kilowatt of energy you generate, thereby helping offset the installation cost.

  1. Cheaper compared to other green heating solutions.

Air source heat pumps are more affordable compared to other eco-friendly heating systems such as ground source heat pumps and biomass boilers.

  1. It can serve both heating and cooling purposes.

Some air source heat pump models are designed to provide heating in winter and cooling in summer. This means that your air source heat pump can come in handy in the heart of winter and help cool the internal environment of your home in summer.

  1. Easy installation

The installation process of air source heat pumps is shorter and less disruptive than that of a ground source heat pump. This is because the installation process does not involve any digging or planning permissions.

  1. Low maintenance

Air source heat pumps are easy to run and maintain, requiring a single visit by a technician once every year.

  1. All-year-round heating

Air source heat pumps can generate heating even in the coldest of winters, meaning you will never stay cold if you have an air source heat pump installed on your property.

  1. No need for fuel storage

Unlike heating solutions such as oil boilers and biomass boilers, air-source heat pumps require no fuel storage as it draws energy directly from the surrounding air.

  1. Long lifetime

With proper care and maintenance, an air source heat pump can last for 20-25 years, meaning you won’t need to carry out a replacement for that duration of time. To put this in context, you will carry out two fossil fuel boiler replacements within the same period it takes to replace an air source heat pump.

Should you buy an air source heat pump?

After reading the many benefits of an air source heat pump, you are probably considering installing it on your property if you haven’t already. However, it is essential to ascertain that the pump would work optimally for your home before making such a significant investment decision. This is particularly so, considering that the efficiency performance of air source heat pumps varies from one household to another.

The reason behind the disparity in performance outputs of similar models of air source heat pumps is down to the existing conditions in your home. As such, you need to pay careful attention to these conditions before moving forward with the installation process.

Some of the factors that determine whether an air source heat pump is suitable for your home or not include:

  • Insulation levels: Air-source heat pumps are best installed in airtight, well-insulated homes for optimal performance. This is because the pumps produce heat at lower temperatures than conventional boilers, meaning drought can significantly impact their efficiency. As such, consider insulating your home and making it draught-proof before installing an air source heat pump.
  • Climate conditions: Air source heat pumps extract heat from the outside air. As such, they would need more power to generate the same amount of heat when outdoor temperatures are lower. Higher energy consumption will lower the efficiency performance of an air source heat pump, and it will not be able to meet its 400% design efficiency rating. This means that an air source heat pump would operate at a lower efficiency in cold climates, and you might be better off installing a ground source heat pump as it would be more efficient.
  • Heating demands: Although an air source heat pump can meet a standard home’s heating and hot water demands, it can quickly become overworked if your home’s heating demand is higher. If this is the case, an air source heat pump alone won’t be sufficient, and you should consider installing it alongside a gas boiler or solar thermal heating to increase heating performance.
  • Type of heating system: Air source heat pumps are usually installed with underfloor heating systems or low-flow radiators. This is because they operate at a lower temperature than conventional boilers, and the hot water in the piping network needs time to release the heat into the surrounding air in a room. As such, you should consider installing an underfloor heating system or replacing your high flow radiators before installing an air source heat pump.
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