What are Air Source Heat Pumps?
Air source heat pumps, also known as air-to-water heat pumps, are a common type of heat pump used in domestic and commercial settings to transfer heat from the outside air to a closed water system within the building — supplying radiators, underfloor heating pipes or hot water storage cylinders.
They are fluid-based systems that work on a similar principle to refrigerators - using electricity to pump fluid through a heat exchange to raise its temperature. This allows the heat pump to convert relatively low outside temperatures to an internal temperature suitable for central heating or for use in baths, showers, and sinks.
Air source heat pumps are the most widely used heat pump type in the UK and are cheaper and simpler to install compared to ground heat pumps.
How much space do I need for an air source heat pump?
When choosing whether to go ahead with an air source heat pump installation, one important factor to consider is the outside space required. You’ll need enough room for the exterior unit to be located — either mounted to the wall of the building or placed on the ground — and enough space surrounding it to ensure sufficient airflow. If you’re not sure about the space requirements, it’s advisable to arrange a professional survey to establish the best placement for your pump.
What types of air source heat pump are available?
Choosing between the two types is a question of both budget and available space.
Split System
In a split system, the components are housed in two units — one is placed outdoors and connects to a separate indoor unit, which in turn connects to the building’s central heating system and hot water storage.
Split systems are more expensive to purchase, require a more complex installation — which adds to the cost — and need sufficient space within the building to place the indoor unit. But as much of the heat transfer happens inside, total system efficiency is higher.
Monobloc System
In a monobloc system, there is a single unit that sits outside the building and connects to the hot water system inside the building directly.
Monobloc systems, having only a single unit, don’t take as long to install and don’t require any interior space, making them an obvious choice for homes or businesses where space is limited. However, as the heat transfer process takes place externally in a monobloc system, efficiency is somewhat lower than in a split system.
Speak to Deseco to get independent advice on the correct type of air source heat pump system to fit your needs, your budget, and the specific characteristics of your home or business.
How noisy are air source heat pumps?
Any significant noise produced by an air source heat pump is due to the large fans which move air across the heat exchange. This happens in the outdoor unit — so there’s no real difference between a split system and a monobloc system in terms of volume.
Under normal conditions, the noise produced in the external unit is no more noticeable than that made by a domestic refrigerator — and as it’s located outside the building, it’s unlikely you will even notice it from inside. If the weather is extremely cold or the unit is heating water to especially high temperatures, the volume will increase, but even so, it should be possible to hold a normal conversation within a couple of metres of the unit.
Different models of heat pumps will have different noise ratings, so if this is a particular concern, it’s worth speaking with a qualified consultant such as Deseco to establish which is the most suitable brand and model for your needs.
Will an air source heat pump work with my existing heating system?
As described above, air source (air-to-water) heat pumps provide hot water to your home or business to supply radiators or underfloor heating. So if you don’t currently have either of these types of central heating systems in place, you would have to install one to make use of this type of heat pump. Although this will obviously increase the total project cost, one advantage of installing both the heat pump and central heating system together is that you can optimise the system for use with an air source heat pump — maximising efficiency and lowering total running costs.
Another consideration is hot water storage.
Air source heat pumps don’t provide on-demand hot water (as you get with a combi boiler), instead, they require a hot water cylinder attached to the system — so if you don’t currently have one, this will be an additional requirement. You’ll also need to ensure you have sufficient space to house a cylinder — the exact size will depend on the specific hot water needs of your property.
Alternative options for homes or businesses without sufficient space to install a hot water cylinder include instant water heaters, which can be fitted to your existing system to provide small volumes of hot water on demand, or a hybrid system where you use a heat pump for your central heating supply and a combi boiler to supply instant hot water for showers, baths or kitchen taps.
How much does it cost to install an air source heat pump?
As we’ve shown above, there are a number of different options when it comes to selecting the right heat pump system for your home or business, as well as additional requirements depending on the system and equipment you already have in place. Costs can therefore vary significantly between projects.
To get an accurate idea of the budget requirements for your own property, speak to Deseco about booking a comprehensive heat design, which will detail the equipment, installation and maintenance costs involved in upgrading your property to an air source heat pump.
