Air Source Heat Pumps

Air Source Heat Pumps

An air source heat pump is a reversible heat pump which uses the outside air as a heat source when in heating mode, or as a heat sink when in cooling mode using the same vapor-compression refrigeration process and same external heat exchanger with a fan as used by air conditioners. We shall explore exactly how it does this below.

Air source heat pump
Air source heat pump

How does an Air Source heat pump work exactly?

An air source heat pump takes heat from the air and boosts it to a higher temperature using a compressor. It then transfers the heat to the heating system in your home. They work a bit like refrigerators in reverse. 

  1. The air source heat pump absorbs heat from the outside air into a liquid refrigerant at a low temperature.
  2. Using electricity, the pump compresses the liquid to increase its temperature. It then condenses back into a liquid to release its stored heat.
  3. Heat is sent to your radiators or under floor heating. The remainder can be stored in your hot water cylinder.
  4. You can use your stored hot water for showers, baths and taps.

What to consider when getting an Air source Heat pump

Installation cost consideration of Air Source Heat Pumps

Prior to installing your air conditioner or what can ultimately be an expensive Air Source Heat Pump, ensure you have sufficiently insulated your house (see Solid or Cavity Wall Insulation, Loft Insulation, Floor Insulation), as otherwise the heat generated is not going to be efficiently used to heat your house. Insulation takes the heating demand down for your property, which allows ASHPs to be effective, given their low flow temperatures.

Offset cost of running Air Source Heat Pumps if possible

Air Source Heat Pumps require electricity to operate (unfortunately). But you can offset this to a degree by having Micro generation technologies installed in your home, e.g. Solar Photovoltaic Cells, Micro Hydro Electric or Wind Turbines.

The Coefficient of Performance is a very important consideration

The Coefficient of Performance (CoP) is a measure of how efficient your heat pump is. For example if 1 unit of electrical energy is input into the Air Source Heat Pump, it should provide about 3.5 of useful heat energy (therefore it has a CoP of 3.5). The CoP varies between different Air Source Heat Pumps, so when buying a unit, remember the higher the CoP the better. The higher CoP Air Source Heat Pumps are usually more expensive (depends with the manufacturer). To get a quote for supply and fit of your air source heat pump and repairs around Johannesburg North; Sandton, Bryanstorn, Rosebank, Houghton, Norwood, Benmore, Morningside, Fourways, Lonehill and Grayston contact Isocool pty Ltd.

Air Source Heat Pumps perform poorly in low temperatures

Be aware that although Air Source Heat Pumps can still extract heat from the air in temperatures as low as -250c, the amount of heat they will provide at these temperatures will be much lower than if you live where there is an higher ambient temperature. So if you live somewhere that has a very cold ambient temperature, potentially look at other self generation energy solutions. 

“Top-up” or secondary heating may need to be installed

The temperature of the water that an Air Source Heat Pump will produce is not as hot as a traditional boiler system, so you may need to consider secondary heating sources that act as a “top-up” heat form. Very popular is a log wood burning stove or an infrared heating panel.

Air Source Heat Pumps may irritate your neighbors

Air Source Heat Pumps produce noise, not a lot, but best to ensure it is not situated directly outside your bedroom or too close to the boundary of your next door neighbor. Alternatively you can contact Isocool pty Ltd to conduct a site survey and identify everything that needs to be done or avoided.

Always follow the latest planning guidelines prior to installation

In terms of planning permission, Air Source Heat Pumps are normally listed under permitted developments so no specific planning permission is actually required, however though this might be the case, you still need to adhere to certain criteria of which the main one is related to neighbors and ensuring there is a suitable distance between your heat pump unit, and their house (please check with your installer / planning authority to make sure you adhere to building regulations).

Positioning of the system will drive its performance

You need to install your Air Source Heat Pump outside where there is a sufficient ambient air flow (we suggest doing so on ground level so it is easy to reach if it needs maintenance). Air Source Heat Pumps work by taking heat out of the air, so if you were to position it in an enclosed space, then it wouldn’t be effective.

Ensure you have a few quotes before you make a decision

As with all serious investments it is worth getting several quotes before investing in an Air Source Heat Pump. We also recommend speaking to other customers of your proposed installer, get their views and put your mind at rest when they tell you they have had a job installed to satisfactory standards.

If you are unsure about where to read up further about Air Source Heat Pumps because the whole thing sounds like a bit of a minefield, then we suggest going Isocool pty Ltd and get first hand information from an the experts. It is worth speaking to an expert so you can get a feel for what the unique capabilities of the systems you are looking to have installed in your property.

Benefits of Air Source Heat Pumps

Energy bill savings

One of the most significant benefits to the consumer of changing to an Air Source Heat Pump is, of course, the saving that can be made on energy bills. This type of pump works by using the air outside the home in order to warm the water pipes, producing both hot water and heating – the system works regardless of what the temperature is outside the home. You might be worried that this type of system will not work to heat your home during the colder winter months, but in fact, it can continue to extract air even when outside temperatures are as low as -15c. Air source heat pumps use air in order to help heat your home and water. This renewable source is readily available, and better still, it is free.

Carbon emission savings

Air source heat pumps are powered by electricity. Unlike many more traditional forms of heating used to heat both your home and water, there is no gas involved. This is excellent news for the environment because it means a significant carbon emission saving can be made. To give a better idea of just how efficient air source heat pumps really are; for every single unit of electricity that the pump uses, 3 to 4 units of heat are produced in the average set up.

Now that we have exhausted the different benefits of having an air source heat pump installed and highlighted where to get the best service for installation and repairs in Johannesburg we now address the big question, which are the brands of air source heat pumps to keep you warm during cold days?Overall, our top window AC unit recommendations for 2021 are:

Which are the best Air Source Heat Pump brands?

Mitsubishi Air Source Heat Pump

Mitsubishi Air Source Heat Pump
Mitsubishi Air Source Heat Pump

Mitsubishi Electric has been manufacturing high-quality electrical devices for well over a century now so it is no surprise they are one of the best air source heat pump manufacturers in the world too.

They offer a wide range of pumps featuring some of the most advanced technology around and also available at extremely competitive prices.

Their most popular air source heat pump is the Ecodan Monobloc. It is a self-contained unit that can work in the most extreme of conditions. Even if it dips as low as -25 °C outside, this air source heat pump can still heat your home. That means unless you live in a place with weather patterns similar to Greenland or Siberia, this is a good pump for you.

The Ecodan Monobloc benefits from being a fairly quiet model and is also extremely low maintenance. It is also at the lower end of the Mitsubishi price range and so represents excellent value for money.

Daikin Air Source Heat Pump

Daikin Air Source Heat Pump
Daikin Air Source Heat Pump

Daikin is a well-known name in the air conditioning market and has a worldwide reputation for its climate control technology. It is, therefore, an obvious company to move into the air source heat pump industry and has enjoyed considerable success.

Their popular Altherma ERSQ AV1 is towards the top end of their range but still offers terrific value for money. It comes with inverter compressors that continuously adjust the compressor speed to the demand of the home. This means you don’t have to do too many system stops and starts which can use up more power. This feature can save an extra 30% of your energy usage.

It’s another model that is fairly quiet and comes with a reputation for being very low maintenance. It can also work in conditions as low as -20 °C. Not the cheapest system on the market but definitely one of the best.

Samsung Air Source Heat Pump

Samsung Air Source Heat Pump

The South Korean electrical manufacturer Samsung seems to be in every market you can think of, so it will come as no surprise to learn they make air source heat pumps too. They have not just jumped on the bandwagon either. Samsung has spent years researching and developing its technology resulting in a product range which is competitively priced and high performing. It is very durable though sometimes due to human misuse its life can be short lived by not t worry as Isocool repairs air conditioners in Johannesburg.

The Samsung EHS Monoblock is at the lower end of the range but offers a superb all-round product. It is a lightweight unit that can be suspended off the ground. It is superbly quiet and works in temperatures as low as -25 °C

A big plus point is its hot water generation which heat water that can be as hot as 55 °C and the entire system is both low maintenance and high-quality. This is a really impressive set-up from a well-known brand. To get a quote for supply and installation Johannesburg contact Isocool pty Ltd.

Nibe Air Source Heat Pump

Nibe Air Source Heat Pump
Nibe Air Source Heat Pump

Nibe is probably not a manufacturer you recognize but they have already developed a fine reputation for their domestic heating systems worldwide.

It has offices around the world and its air source heat pumps are amongst the most energy-efficient on the market. Their units have all been designed with ease-of-installation in mind and every model comes with an anti-vibration water connection.

In particular the F2040 range comes with a NIBE Uplink app that can provide you with a quick overview of the device and the current status of the heat pump and your heating system. If there is ever a problem, your app will send you a notification to allow you to remedy it as soon as possible.

Air source heat pumps are among our of the most popular modern methods to heat up homes and unlike traditional air conditioners have the added advantage to reverse roles between heating and cooling the air inside a room. If ever you need help with window air conditioner repairs in Johannesburg then Isocool pty Ltd will have you sorted in no time. Contact Isocool pty Ltd for any other air conditioner needs in Johannesburg.

Also if you are looking for an air conditioner in Johannesburg for your home, office, or shop, then get in touch with Isocool pty Ltd for a site survey and expert advice.

Call us now at (078) 922 2884 or send us an email: to book for an appointment.

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Your comment will be published within 24 hours.


  • hawkmechanicalservices
    4 November 2022, 2:16 pm REPLY

    I agree. Because of their high efficiency and the increasing share of fossil-free sources in electrical grids, heat pumps can play a key role in electrification, the energy transition, and climate change mitigation.

  • Jay, Carrier HVAC
    25 February 2023, 3:46 am REPLY

    Thanks for sharing, air source heat pumps are a popular and effective way to heat and cool a home because they use less energy, are flexible, and are easy to install and keep up. But when choosing an ASHP system for a certain application, it’s important to think about things like the climate, the size of the building, and the budget.


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