Like many organisations and companies across Scotland, The Gannochy Trust is working hard to reduce its carbon footprint and drive towards Net Zero.
In 2022, the Trust formed its Carbon Footprint and Action Plan, where, in partnership with Carbon Change Ltd, it set out plans to establish a carbon footprint baseline, identify and support carbon reduction opportunities and establish a net zero pathway.
The baseline study revealed that across all the Trust’s operations, 1052 tonnes of carbon were being emitted each year, not including tenant farmers operations. Interestingly, 75% of these emissions were generated from residential emissions, namely gas boilers.
The report concluded that if all residential properties were to have Air Source Heat Pumps (ASHPs) installed and all fossil fuel technology – for heating and hot water – were eliminated, along with the installation of residential Solar PV, there would be a 68% reduction in carbon emissions, equating to between 700-800 tonnes of carbon a year.
Recommendations from the report included the commencement of reviews of all the relevant technologies that could supply heat and electricity to the Trust’s housing stock. It was subsequently agreed that pilot trials of the short-listed options should be carried out with pre and post implementation reviews to determine the most economical, technically viable solutions that would simultaneously deliver carbon savings.
Fast forward six months and the first pilot trial is nearing completion. 8 Brands Brae, one of the original Gannochy houses dating back to the 1920s, underwent a six-month refit, including significant upgrades to the insulation of the floor, walls and roof; improvements to the air tightness of the building; and an air source heat pump to replace the gas boiler.
Insulating a property more than hundred years old constitutes a significant challenge, however the team managed to achieve an impressive airtightness of 4.25 m3/(m2.hour) at 50 pascals. This is comparable with the Trust’s recently new houses which perform at between 3.5 to 5.5 m3/(m2.hour) at 50 pascals.
Part of the success was down to the rigorous approach to insulation, which included the installation of a special membrane under the floor to reduce upward draught generated through ventilation bricks.
With thick external walls made of stone, the team also had to contend with the risk of interstitial condensation. The insulation had to be carefully regulated to ensure the external walls remained dry within the inner reaches of the masonry.
The air source heat pump has performed remarkably well, heating the house to a balmy 22 degrees, even during a recent cold snap when outside temperatures dipped below freezing.
This impressive initial performance came with reasonable economic impact, with the heat pump using around 1 kilowatt of electrical energy an hour.
Following the initial success of the trial, the Trust has plans for a further two pilots over the next 6 months. The aim is to install different set ups within each property, such as replacing the under-floor heating installed in the initial pilot with radiators, to explore a range of solutions addressing energy efficiency and tenant satisfaction.
Suffice to say, the upgrading of properties with low carbon technologies will come at considerable cost, so these initial pilots will allow the Trust to identify the most technically appropriate and cost-effective solutions. Following the pilot phase, the Trust will be able to plan its refurbishment programme to ensure the work undertaken aligns with its long-term carbon reduction aspirations.
Andy Duncan, Chief Executive of the Gannochy Trust welcomed the pilot projects commenting “In an uncertain world with rapidly changing energy technologies these pilots help to inform the range of options available in addressing decarbonisation and ensuring our housing stock remains fit for purpose into the 21st century.”