A prestigious Grade II listed estate, nestled near Loch Ness in the Scottish Highlands, is on track to save more than £100,000 in energy costs over the next two decades following the installation of five aroTHERM plus air source heat pumps.

While the original building at the Loch Ness Hunting Estate, was constructed in the 15th century and is Grade II listed, an additional lodge is also situated on the grounds, which was constructed in 2009. This blend of modern and historic construction meant that when the existing electric heating system became inefficient and began to deteriorate, a unique set of system design and installation challenges needed to be overcome to ensure the building’s heating and hot water requirements were met.

Providing a picturesque base for up to 12 visitors to stay when visiting the area, the estate’s owners were keen to invest in a sustainable heating solution that would meet the bespoke needs of the property and its guests. This meant the existing oil-fired boiler and electric radiators, which were installed in the listed building, needed to be replaced with a low carbon alternative that also delivered optimised energy efficiency.

Additionally, whilst the focus was on sustainability, with nature being a key draw for guests staying at the estate, the site’s owners were keen to minimise the impact on local wildlife and their habitats. It was essential that the heat pump units were quiet. Therefore, Vaillant’s air source aroTHERM plus heat pump was specified, following a review of the estate’s existing heating demand and the customer's criteria.

Drawing on Vaillant’s industry-leading expertise, as offered under The Vaillant Standard, the project’s installers, McInnes Group Limited, worked closely with Vaillant’s design and specification teams to create an ultra-efficient heat pump cascade rig. To support the heat pump cascade located outside, the internal components were housed in a purpose-built plant room, together with five Vaillant uniSTOR 300L hot water cylinders and additional VRC 700 controls.

As a result of installing the bespoke heating system, the estate has been able to take advantage of the aroTHERM plus’s excellent ErP efficiency rating of A+++ together with impressive SCoP values of up to 4.88 for heating and 1.75 for domestic hot water. This means the new low carbon heating system is estimated to save the client £4,000 annually on heating bills across the two properties heated by the system.

To further bolster the sustainability credentials of this impressive site, McInnes Group opted for a lower flow temperature for the system at around 40°C for a large portion of the day, further reducing the site’s energy bills.

With the estate used commercially, the installation was eligible for RHI repayments of over £4,000 per year over 20 years on top of the heating bill savings already identified.

This, combined with the energy savings achieved through installing the aroTHERM heat pump system, means this installation has the potential to save the estate more than £100,000 over the next two decades. While from a carbon saving perspective, the installation is estimated to save around 24.31 tonnes of CO2 annually, when compared to the estate’s legacy oil system.

Lachlan McInnes adds: “We’re seeing more homeowners looking to low carbon heating technologies, and while not every home is going to be Grade II listed this project shows that heat pumps can have a place within older buildings too.

“By working closely with the customer from the start, we were able to lean on the support offered by Vaillant to develop a heating system which serves the needs of the property both today and into the future.”