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Out with the old

A combination of the Renewable Heat Premium Payment and Daikin heat pumps brought a Cornwall housing block significant energy efficiency gains, and the praise of Cooling judges

Coastline Housing has undertaken an eco upgrade* at 18 flats in Porthleven, Cornwall as part of the government’s programme to install 7 million such upgrades throughout the country by 2020.

The 18 flats in Matela Close, which are off the gas grid, occupy an exposed hillside coastal location. Built in the early 1960s, they were in need of refurbishment. The wall construction is a mix of cavity and single skin solid wall and, until the upgrade, the primary heating system was provided by electric night storage heaters with secondary open fires and back boilers. Communal hot water tanks in the loft were not ideal, as they required high cyclical cleaning maintenance to eliminate risk of Legionella.

The homes were assessed by Coastline’s refurbishment manager as worthy of a bid to the Renewable Heat Premium Payment (RHPP) Phase 1 Social Landlords Competition. Following extensive communication and discussion with tenants, work to upgrade heating systems with Daikin Altherma air-to-water heat pumps started in January 2012 in very challenging winter weather and continued until the end of March.

This meant it was completed within the very tight RHPP bid deadline. Work was carried out by local heating engineer contractor Blueflame (Cornwall).

Immediately following this work, a phenolic external wall insulation system was installed with a calculated target U-value of 0.3 to complement the new heating systems. All flats were occupied during works and local contractor W Hudson & Sons was used throughout. Monitoring equipment has been installed by the Department of Energy & Climate Change to record energy consumption and Coastline is monitoring fuel costs and so-called soft outcomes such as tenants’ well-being.

As a result of the refurbishment, the flats have been transformed, in terms of thermal efficiency. Sixteen of the 18 flats have had the outdated electric night storage heating systems replaced with Daikin Altherma 6kW monobloc heat pumps.

Open coal fires with back boilers have been removed and sealed, together with redundant chimneys. The installations have been innovative – monobloc heat pumps were used to save space within each flat; hot water cylinders were located in redundant coal stores in stairwell landing areas; and mixer showers were installed to take full advantage of energy efficiency savings. Communal hot water tanks in the loft areas have been drained down and disconnected.

Ralph Retallack, retrofit project manager for Coastline, says: “The Daikin Altherma air-to-water heat pumps are well-known and proven to Coastline both in terms of running costs and functionality and have been used extensively in our planned heating programme for off-gas properties where oil is no longer a viable option. Additionally our heating engineer, Blueflame, was familiar with Daikin UK, giving further confidence that the installation would be successful in the very tight timescales available.”

The project has been a huge success with tenants, according to Mr Retallack. “This has had a positive impact on the lives of the people who live in these flats. It is difficult to quantify the “soft outcomes” such as well-being, happiness, contentment etc. However, people’s attitude to living in the Matela Flats is now positive and much pride has been restored.”

Almost all of the residents of the flats qualify as Priority Group tenants with three of the households being in the Super Priority Group. Many properties were inadequately heated or not heated at all. The flats now have a comfortable living environment and damp has been eliminated due to the improved internal temperature. It is expected there will be significant derived health benefits, particularly for respiratory conditions.

Mr Retallack concludes: “Following the work, one tenant told me of an incident which sums up the benefit to residents. The refurbished flats were being discussed enthusiastically in the local shop. She said: ‘I told them that I live there and I was really proud.’ Far from being a depressing building it is now stands proudly among surrounding properties attracting positive attention.”

*An eco upgrade is defined as the installation of a set of measures beyond basic insulation, and may include the installation of smart meters coupled with solid wall insulation or, alternatively, the installation of loft and cavity wall insulation with a form of renewable energy generation such as a ground or air source heat pump.

Matela Close

Carbon savings/energy efficiencies delivered by the installation (calculated using the OFGEM calculator for CERT funding):

  • U-value before (W/m2K): 2.1
  • U-value after (W/m2K): 0.35     

Matela Close flats are two-bed. Therefore, based on 18 flats, the annual carbon saving arising from external wall insulation on this building is: 18 x 992 = 17,856 kg CO2 per annum.

Carbon saving arising from installation of air source heat pumps has also been calculated using the OFGEM calculator:

  • Space COP: 3              
  • Water COP: 2.4           

Based on the two-bed flat carbon saving, the total per annum saving can be calculated: 16 x 2687 = 42,992 kg CO2 per annum (note that two of the 18 flats chose not to be upgraded).

Total carbon saving for the project works based on this desktop calculation is approximately 61,000 kg CO2/annum.

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