Power to the people

Kensa's David Broom and John Bruton with Leon Storer from Stonewater at Burton Gardens

The housing sector is responsible for a large portion of carbon emissions in the UK, so if there is any hope of hitting the government’s target of net-zero carbon emissions by 2050, the way in which we heat our homes needs addressing. However, with five million homes in the UK social sector, there is a mammoth task ahead in order to create housing that fits the bill.

Stonewater has committed to playing a key role in achieving the national net-zero carbon target and has been exploring how innovative low-carbon heating technology can help realise this ambition.

“With rising energy costs forcing more vulnerable people into fuel poverty, there is a real need for social landlords and housing providers to help tackle the problem, which affects thousands of people across the UK,” says Nick Harris, Stonewater’s chief executive. “Effective measures such as replacing night storage heaters with more efficient, affordable and carbon-friendly home-heating technologies can make a big difference to people’s lives, particularly their health and wellbeing.”

Breaking the mould

In 2017, CIPHE Industrial Associate Supporter, Kensa, partnered with Stonewater to deliver a pilot ground source heat pump project at a site in North Herefordshire, with the aim of providing residents with warmer and cheaper home heating systems.

The scheme at Burton Gardens, near Weobley Village, involved replacing the night storage heaters in 49 bungalows with Kensa’s Shoebox ground source heat pumps. It features Kensa’s innovative Shared Ground Loop Array system architecture to serve the individual properties.

“An average two-bedroom bungalow typically costs £800 a year to heat with night storage heaters, compared with £390 from a ground source heat pump,” explains Harris. “Our Burton Gardens residents have seen a significant reduction in their energy bills with their new ground source heat pump system, which enables them to heat their homes at an affordable cost and stay warm during the cold winter months.”

Ground work

Ground source heat pumps are a tried and tested technology that have been shown to produce significant carbon savings and low running costs, which is why Stonewater chose this route.

Ground source heat pumps are electrically powered, non-combustion devices that produce no local emissions or air pollution. Using freely available and naturally replenished heat energy, stored just below the surface of the ground, they can achieve higher efficiencies than any other heating system.

Properties in Burton Gardens where storage heaters were replaced were predicted to save around 40% of their running costs and the ground source heat pumps reduced the carbon output associated with heating each home by around 70%.

Fuel poverty

The new heating system had a big impact on people’s lives by providing warmer, more comfortable homes and substantially cutting their energy bills, while reducing their carbon footprint. The social housing provider’s commitment to reaching net zero carbon also enables clean heating to be brought to people that otherwise may not be able to afford it.

According to Community Action on Fuel Poverty, 4.5 million UK households are living in fuel poverty and struggling to heat their homes. The primary causes of fuel poverty are low incomes, high energy bills and energy inefficient homes, which is why the government is keen to implement more efficient methods of heating in homes.

“Fuel poverty is a significant problem across the UK and one that has been exacerbated by the pandemic and increasing utility prices,” says Adam Masters, environmental sustainability manager at Stonewater. “It is crucial that social landlords mitigate the risk of fuel poverty and continue to improve the efficiency of their homes, alongside supporting customers to access cost effective energy tariffs and maximise their income.”

Stonewater has set a target to improve all of its existing homes to a minimum EPC rating of Band C by 2030. One way in which the social housing provider is achieving this target is through upgrading heating in some of its homes, working in partnership with Kensa.

“We are also developing other measures to support our customers including energy saving advice videos and we recently employed a fuel engagement specialist to provide more in-depth support for those customers in need,” explains Masters. “At Stonewater, we put customers at the heart of everything that we do, which is why it is so important that we find solutions to decarbonise our homes, whilst reducing running costs for customers.”

Getting pumped Kensa has pioneered an innovative district heating infrastructure, known as an ambient Shared Ground Loop Array system, which allows ground source heat pumps to be installed in multiple properties or shared occupancy dwellings. Clusters of communal ground arrays, typically boreholes, act as the heat source for a loop of ambient temperature pipework, which feeds heat to decentralised ground source heat pumps installed inside individual dwellings.

Each property contains an individual ground source heat pump, meaning all heating and hot water is delivered and, more importantly, billed at the point of use. This removes the need for individual metering and the administration and management cost of managing a traditional district heating scheme. This also allows residents to shop around for the cheapest electricity tariff to ensure running costs for the system are minimal.

As the residents have independent control over their own heating and hot water, the temperature within the buildings’ pipework is kept between -5°C and 20°C (ambient), only being upgraded when a heat pump calls for heating and hot water. This greatly minimises the problem of overheating within multiple occupancy buildings, reducing heat losses and therefore residents’ energy bills, while maximising the overall efficiency of the system.

“Individual heat pumps help residents with the lowest possible running costs and individual billing, while the communal ground array allows the housing association to access funding and maximise efficiency as there are no system distribution losses,” explains David Broom, commercial director of Kensa Contracting. “Running costs for this type of system compare well to mains gas boilers, with half the carbon footprint, and have been proven to deliver the lowest carbon emissions of any renewable technology.”

Super savers As a result of the pilot project in Weobley, many of the residents’ heating bills have halved, with some reporting savings of hundreds of pounds annually, following the installation of the ground source heating system.

“We have had some really positive feedback from our residents, with some describing the new system as ‘life changing’,” reveals Leon Storer, assistant director of Homes – capital investment, at Stonewater. “They’ve gone from struggling with uncontrollable expensive night storage heating, which often would have run out by the time they needed it in the evening, to fully controllable, affordable heating.”

The borehole installations located 150m below ground level are providing an infrastructure which will deliver 75% of the heat required for these properties, for free, for the next 100 years.

The homes are warmer, more comfortable and the cost of heating is significantly reduced. Residents are also protected from future cost increases as the majority of the energy required comes from the ground beneath their homes.

“For every ground source heat pump installed at Burton Gardens, we took the equivalent carbon emissions from two cars off the road,” says Broom. “It is vital to work with forward-thinking housing providers like Stonewater to improve the condition of the UK’s housing stock.”

These projects are vitally important because they demonstrate that mass decarbonisation needs to be deployed strategically on a community-wide, street-by-street basis and at even greater scales, to get to the projected 600,000 heat pump installations a year required to meet the UK’s current carbon reduction commitments.

Crunching the numbers

The heating upgrade at Burton Gardens cost the housing organisation £700,000 to install. However, the scheme was subsidised by an upfront ECO grant of £95,000 and had an expected payback of 16 years, with Stonewater receiving an additional £800,000 income over 20 years from the government’s Non-Domestic RHI scheme.

Although the Non-Domestic RHI closed to new applications in March 2021, there are a number of grants currently available that can support projects and to incentivise the adoption of ground source heat pumps in the UK.

Find out more on the Kensa website.

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