How Much Space does an Air Source Heat Pump Need?

Unlike a ground source heat pump, air source heat pumps can be installed with relatively little sacrifice to space inside or outside your property.

Air source heat pumps extract heat from air outside your property and use this to heat water inside your home. Here is how air source heat pumps work.

Air source heat pumps aren’t the largest but do require space to be installed.

Here is how much space you will need to install an air source heat pump both inside your property and outside.

External space needed for an air source heat pump

Air source heat pumps are typically installed on the exterior of properties. This allows them to capture cool air from outside extract the temperature from the air and use this to heat water within your property.

The now cooled air is then expelled. As the process continues, the water continues to heat until enough temperature is delivered to the water to make it suitable to heat your home, use for showers and baths and for day to day activities like washing up and cleaning.

When installing a heat pump outside your property you will need;

  • a flat concrete (or alternative solid, stable surface) to mount your heat pump
  • 1 – 1.5 metres of vertical space to fit the heat pump standing upright
  • 0.5 – 1 metre of width for your external heat pump unit
  • at least 1.5 metres of unobstructed space in front of the heat pump fans to prevent air flow away from the heat pump being obstructed to prevent cold air from being recirculated through the heat pump.
  • space for pipes to deliver heat into your property, the size of which will vary.

Depending on the type of heat pump you choose, you may be able to install the heat pump flush against your exterior wall, or you may need to leave a small gap.

Air source heat pumps can be noisy, although it’s not usually intrusive. However, some installers recommend that you don’t install them on the outside wall of downstairs bedrooms.

Air source heat pumps don’t require planning permission because they are considered permitted developments.

Internal space needed for an air source heat pump

Similar to ground source heat pumps, you will need to ensure you have interior space for both;

  • the heat exchange unit (roughly the size of a conventional gas boiler, 0.7m height x 0.3m depth x 0.4m width)
  • a hot water cylinder (these are normally about 1.5m x 0.7m)
  • A monoblock heat pump system is also an option, the heat pump and water cylinder are combined in a single unit. (monoblock heat pumps are approximately the size of a fridge freezer (1.91m height x 0.6m width X 0.65m depth)

Radiator Sizes for a Ground Source Heat Pump

Air source heat pumps have a lower flow temperature than a gas boiler, usually around 35° – 45°.

Because of this lower flow temperature you will need to also install larger radiators to help keep internal temperatures stable and evenly distribute heat throughout your home, even when temperatures drop outside. Recommended radiator sizes for ground source heat pumps are usually recommended to be 2.5 times larger than ordinary radiators installed for a gas boiler.

  • 10 radiators in the average home at around; 0.4m x 0.4m (0.16 square metres, per radiator or 1.6 square metres in total)
  • 10 radiators x 1m x 1m (1 square metre per radiator or 10 square metres in total)

A recommended alternative to radiator upgrades can be underfloor heating but underfloor heating can be expensive.

Air Ducts to Send Cool Air Around your Property

If you want your heat pump to offer cooling setting and act as an air conditioner in the summer months, you will need air ducts installed in your home that allow your heat pump to send cool air through.

The cheapest types of air ducts available are spiral duct fittings, they’re usually between 80 – 1600mm in diameter and made from galvanised steel, aluminium or stainless steel.

HVAC systems are also an option if you’re looking for a system which handles heating, ventilation and air conditioning.

HVAC systems vary in size and the square footage of your home will affect the type and size of HVAC system you need.

Systems can be around 1010mm width x 549mm height x 165mm depth but could replace existing air conditioning units.

Total Space Required for an Air Source Heat Pump

External space: 3.5m squared for the external heat pump unit Internal space: 13.6m squared for internal heat pump components, water cylinders and large radiators or HVAC systems to distribute heat around your home.