Air Source Heat Pumps: how they work, costs, reviews

air source heat pump exterior

Air source heat pumps are becoming an increasingly popular way to heat homes. They are a cost-effective alternative to central, electric or storage heating. Primarily, they work by moving outdoor heat indoors, or vice versa. They can either be used on their own or as a complement to a gas-based heating system. Having a well-insulated home helps to get the most out of your heat pump. Find out if air source heat pumps are for you.



How do air source heat pumps work?

An air source heat pump (AHSP) is installed outside the house. The pump captures heat from the surrounding air outdoors and releases it inside the home. Air source heat pumps consume electricity as they operate but when compared to other types of heating they are more energy efficient.

 

Heat pumps can both heat up and cool your home depending on the time of the year. They essentially work like a fridge in reverse. In the winter, they make outside air colder by extracting its latent heat and bringing it into the home. In the summer, the same thing happens but in the opposite direction; the inside of the house is like a fridge where heat has to be removed and pushed outside.

A refrigerant liquid is used to capture heat from the air so it can be sent into a compressor which increases its temperature. This hotter fluid can then transfer this captive heat to the heating and hot water systems in your home.

The heat pump cycle works as follows:

  1. The refrigerant liquid goes through the outdoor circuit at a very low temperature. So low, in fact, that the liquid is heated by residual heat outdoors to the point that it boils and turns into a gas.
  2. The refrigerant liquid goes through the outdoor circuit at a very low temperature. So low, in fact, that the liquid is heated by residual heat outdoors to the point that it boils and turns into a gas.
  3. As the gas moves over into the indoor coils past the pressure valve, it cools down and becomes a liquid again.
  4. As the gas cools back down into a liquid, it releases the heat it built up in the previous steps.
  5. The liquid moves back out to the outdoor coil and the process starts again.

How much do they cost?

While air source heat pumps are cheaper than their ground-based counterparts, they are still quite an investment. Residential air-source heat pumps can run anywhere between £6,000 and £8,000. However, with the UK seeing rising summer temperatures in the south, AHSP systems do have an ace up their sleeves: they can work in reverse too and cool your home during hot weather.

According to Jon Davies at Great Home, a website that specialises in home improvement advice, installation costs for a new system can vary greatly according to the type of home. Let’s have a look at how Air Source Heat Pumps stack up against standard gas boiler based systems.

Boilers vs. AHSP cost comparison
Home type Air Source Heat Pump System Cost Gas Boiler System Cost Difference
Detached house £9,200 £7,750 +£1,450
Semi-detached or terraced house £8,000 £5,500 +£2,500
Low rise flat £6,400 £5,600 +£800

If you are considering getting a heat pump for your home, you will also have to factor in the installation. Even if the setup cost is included in your heat pump quote, it’s worth checking the installer’s credentials and reputation. Cutting corners on installation will come back to haunt you when you need to maintain your system.

Most installers who deal with AHSP systems will have experience with boilers and other renewable technologies, such as solar panels. Heat pump technicians should preferably be Gas Safe registered and have the correct endorsements for this type of installation.

In terms of maintenance, heat pump owners are looking at similar inspection schedules and costs as regular gas boilers. Households can expect a basic two or three-year warranty as standard for their heat pump. There are also various warranty extension options available directly from the manufacturer, for an extra cost. For example, you can expect an average of about 20 years when it comes to operational life. There are early heat pumps installed in the seventies that are still going strong. Yearly checks and then more in-depth inspections every three to five years is the way to go to keep a heat pump system in tip-top condition.

How much can you save?

Savings, and how soon you see them, greatly depend on how efficient your ASHP system is when compared to your old boiler or heating system. The answer to this question also depends on whether you’ll be taking advantage of the Renewable Heat Incentive scheme.

Let’s take a look at some potential savings figures for a medium-sized four-bedroom home.

Estimated annual savings compared to previous heating system
Old heating system Potential annual savings
Old gas boiler (G efficiency rating) £400 - 455
Old oil boiler (G efficiency rating) £460 - 540
Old electric storage heaters £800 - 990
Old LPG boiler (G efficiency rating) £1,140 - £1,320

Be aware, that these estimates do not include Renewable Heat Incentive payments that you may be eligible for. These payments can range anywhere between £800 to £1,000.

If you have a newer boiler or heating system, you are probably getting relative energy savings already. Swapping out a recent system for a heat pump might not be worth it purely for economic reasons. Namely, you could end up paying anywhere from £35 to £55 more every month if you do so.


Advantages and disadvantages

Air source heat pumps can seem almost magical in the way they pull heat out of thin air. That doesn’t mean that they are necessarily the silver bullet for all British heating and hot water needs.

Heat pump benefits

The pros of having ASHP are based around energy efficiency and sustainability:

  • Reduced energy bills in most cases, especially if coming from electric or storage heating.
  • Increased energy efficiency means that air source heat pumps cause fewer greenhouse emissions.
  • Heat pumps are powered by electricity which means that they can operate entirely off renewable energy, such as solar, tidal, biomass and geothermal energy.
  • UK heat pumps may be eligible for Renewable Heat Incentive payments.
  • Some models can still produce heat even in extremely cold conditions.
  • They work both for space heating and hot water applications.
  • Easier to install than ground source pumps, which require digging up a fair chunk of your garden or yard.

Heat pump drawbacks

The cons of having heat pumps mainly centre around perceived convenience and setup costs:

  • While not as space-hungry as their ground-source cousins, they still need space outdoors, comparable to an air conditioning unit.
  • They have lower heat output when compared to oil or gas boilers. Larger radiators may be needed.
  • Underfloor or warm air heating is needed to get the most out of a heat pump.
  • Homes with poor insulation will not benefit from heat pumps.
  • Currently, heat pumps aren’t as cost-effective as natural gas powered heating methods due to the cost of electricity.

Are heat pumps suitable for my home?

At the moment, heat pumps will provide the most value for money for homes that are not connected to the natural gas grid. For years, homes without natural gas have had to contend with expensive options for heating and hot water. Heat pumps provide significant savings and convenience when compared to oil, electricity, LPG and solid fuels like wood or coal.

To maximise heat pump efficiency, it’s best to go for underfloor or warm air heating if possible. Since air pumps work by essentially sucking up latent heat from outdoors to put it indoors, good insulation is crucial to get the most out of a heat pump system in your home.

If you live in an older home with poor insulation, putting in a heat pump should be part of a broader home improvement investment including better insulation and window glazing to maximise energy efficiency.


Air Source Heat Pump Reviews

Here are some of the top Air Source Heat Pump brands with models available in the UK. Let’s take a look at what each one offers.

1. Worcester Bosch Greensource

While they are a household name when it comes to traditional boilers, Worcester Bosch has also begun to offer a range of AHSP models called Greensource. Their heat pumps have built-in air purifiers which makes them a great option for households with allergy sufferers.

Additionally, they also offer compact models that make installation easier and remote control features that let you operate the system smartly from anywhere in your home, making them significantly more convenient.

2. Samsung Eco Heating System

The Samsung brand has always been associated with the consumer technology sector, whether it’s 4K TV’s or the latest smartphones. However, they are deeply invested in ASHP manufacturing as they leverage their past expertise with air conditioning units.

Their Eco Heating System (EHS) is most notably offered in an all-in-one flavour with their TDM technology, which is particularly well-suited to homes with under-floor heating.

Samsung tends to push for integrated Air Source Heat Pumps that allow for speedier installation by coming with an included hot water cylinder and a rapid connection board. They have a wide range of heat pump and air conditioning products for a variety of budgets and needs.

3. Hitachi Yutaki

Hitachi is a Japanese company with a long history in the technology and manufacturing sectors. Their ASHP range is called Yutaki, named after a famous waterfall in Japan. Their range is further divided into two product lines.

The M-line is an outdoor space-saver AHSP which gives users a remote control for setting temperatures. The Yutaki-M is easy to recommend for newly-built homes. The S-line features a more complex design with both indoor and outdoor systems. The Yutaki-S is so powerful it can even heat water to up to 60ºC, making them ideal for heating up swimming pools!

If you have already spent money on a new hot water tank, the Yutaki S80 might be a solid option. It’s a split system, meaning it has both outdoor and indoor parts, that can heat up water to 80ºC and provide five-fold efficiency gains when compared to standard central heating systems.

The Hitachi models also have easy-to-use holiday settings to keep your home at a constant temperature when you are travelling. This can help to protect it from water damage due to extreme cold temperatures.

If you choose to go with a Hitachi heat pump, you should insist on contracting an accredited installer so you can get their exclusive full 7-year parts and labour warranty.

4. Dimplex LATU

Dimplex are not a household brand but that doesn’t mean they lack expertise. With 70 years of experience with electric heating, they are well placed to be a successful heat pump manufacturer.

Their Air Source Heat Pumps fall under the LATU range and can uniquely handle significant heat demands, which makes them ideal for larger homes and even in professional settings. Dimplex can put out anywhere between 17kW to 45kW of heat from a single heat pump. High output coupled with high efficiency means lower costs for demanding users.

Their products are also notable for their soundproofed fans and electronic speed control which helps to mitigate noise.

5. Mitsubishi Electric Ecodan

Mitsubishi is another household name that is very much respected in the heat pump industry. With Ecodan heat pumps, the company aims to cater to residential homes as well as retail and commercial buildings.

The Ecodan PUHZ Monobloc model is specifically designed for homes by keeping noise down, thanks to its single fan compact outdoor design. Mitsubishi also manufactures heat pumps that can resist corrosion from seaside locations, which should appeal to coastal households.


Air Source Heat Pumps: Our verdict

Here at theSwitch, we believe that Air Source Heat Pumps are an ideal heating and hot water option for most new homes. They are also a good choice for those with well-insulated older homes looking for an energy-efficient and sustainable upgrade to provide them with savings and a green peace of mind.

For rural or remote homes which have been stuck between a rock and a hard place when it comes to choosing LPG, oil or expensive electric heating, AHSP represents a real alternative that can be easily installed and maintained.

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Technology Guides