Air Source

Tower Road, Dorset

Exhaust Air Heat Pump Case Study
Salthaven Apartments, Tower Road, Poole, Dorset

Salthaven Apartments, Tower Road, Poole, Dorset

The Salthaven apartments in Dorset aimed to deliver luxury living for occupants. Bayview Developments not only constructed beautiful homes for them, but also opted for highly energy efficient heating within the new development.

Each of the 12 two or three bed apartments have been fitted with their own individual exhaust air heat pump (EAHP). This technology has been installed in buildings across continental Europe for many years but is now being used more commonly within the UK. Bayview Developments were looking to exceed their planning requirements by reducing carbon emissions and providing cost savings for occupants. NIBE’s innovative EAHPs were therefore the ideal solution.

The solution to the project

A NIBE F730 EAHP system removed the need for gas boilers, something Bayview were keen to do given the UK’s net zero targets and commitment to phase out the technology. As heat pump technology is powered by electricity, no gas has been installed at the site.

The NIBE F730 unit can be found in the utility room cupboard of each apartment and is comprised of a ventilation system, a hot water cylinder and a heat pump – a complete ‘all-in-one’ product. It works by drawing warm air from the kitchen and bathroom to feed the heat pump which extracts the heat and energy. This is then transferred to heat the water for underfloor heating and is deposited in the integral cylinder for readily available hot water. The stale air is then released outside, whilst fresh air from outdoors is introduced via wall inlets with cleanable filters. The efficient system minimises energy consumption by using existing warm air that is perfect for well insulated new build properties such as these.

The Results

The EAHP systems meet the annual heat demand of 6019 kWh for all 12 flats whilst also providing instant hot water. Occupants are able to schedule their heating to suit their timetable and energy tariffs, and therefore benefit from lower energy bills. The system performance factor (SPF) measures 3.33 – this means the system is very efficient as every kW of electricity used to run the unit produces approximately 3 kW of heat energy.

NIBE utilised connected electricity meters in 3 apartments to remotely monitor the systems performance across a 12-month period. NIBE was thus able to see how the systems met energy demand consistently for residents, keeping them comfortable and warm throughout the year.

Energy consumption data shown in Figure 1 visualises electricity consumption data from the monitored apartments throughout the year. This data also covers the provision of all heat pump controls and continuous mechanical ventilation.

Figure 1

Figure 1: 2022 Energy Consumption data for monitored apartments.

The all-in-one system has shown a noticeable reduction in energy bills for each apartment too, with all 3 monitored apartments experiencing both monthly and cumulative cost reductions in their energy bills as shown in Figures 2 and 3. This comes with the additional peace of mind that consumers will be kept cool in the summer months with ventilation with no increase in costs.

Figure 2

Figure 3

Figure 2 and 3: Monthly and Cumulative Heating Bills for Apartment 11 with the NIBE F730 heat pump compared to a natural gas boiler.

The occupants of Apartment 11 are saving on average £130 on their annual heating bills with the heat pump system in comparison to a natural gas boiler, even with the additional provision of mechanical ventilation. We expect that these savings will continue to increase as the Government seeks to rebalance green levies to decrease electricity prices.

Sunstone Energy Ltd, the installer for this project, told us how easy the control system is to use for this heat pump, allowing for heating and hot water to be available at any time during the day. The building also benefits from insulation, underfloor heating, smart controls, double glazing, hot water cylinders and mechanical ventilation with heat recovery (MVHR).


Victoria and John are both residents of the Tower Road apartment complex and have been comfortably living with the exhaust air source heat pump system for a year. They added “We are delighted so far with the new heating system, and love that it has been providing us with heating and hot water throughout the year, keeping us warm in the cold winter months. The heat pump works just as well as our older systems and it is great to know that we’re also doing our bit for the environment in the process.”

About the installer

Sunstone Energy Ltd takes responsibility for delivering complete renewable solutions appropriate to their client’s properties. Their expertise includes the installation of ground source and air source heat pumps, underfloor heating, solar panels, biomass boilers and MVHR.  

NIBE Case Studies

More Case Studiesesc