A major element of the project was the replacement of the existing space heating and domestic hot water systems in the flats. “Originally the flats were heated using electric underfloor heating, with domestic hot water from point-of-use water heaters,” recalled Mark Ashley of British Gas. “The space heating was controlled centrally, which meant that tenants had no local control of temperature, other than by opening windows and wasting energy,” he added.

Lawtech’s Tony Adshead added: “The new system uses gas-fired condensing boilers on the roof of each block, serving newly-installed radiators and hot water cylinders in each flat through the FlatStation units. The flats have also been fitted with thermostats so that tenants can control their heating efficiently, as well as thermostatic radiator valves for enhanced local control within each flat.”

As a result of this major refurbishment, each flat now has full control of heating and hot water via a programmable room thermostat/timer, so that residents are able to configure the system to their own requirements.

Each FlatStation incorporates differential pressure and temperature control. The integral differential pressure control valve ensures optimal hydraulic balancing of the primary central heating network, resulting in reduced flows, reduced heat losses and increased pump performance. As well as optimising the system from a design perspective, this also reduces the building’s energy and maintenance costs.

A further benefit is the ability to maintain a low, constant differential pressure across the control valve, prolonging the life of the control equipment and enabling the low return temperatures which are crucial for the energy performance. Another advantage is that space heating and domestic hot water demands in one flat do not affect availability in the other flats. Thus the occupants have instantaneous domestic hot water on demand, accurate temperature control and lower energy bills.

The project was funded through the Community Energy Saving Programme and involved a range of other measures to improve the energy performance of the buildings. These included replacing existing wall cladding, insulation of the roof spaces and enclosing existing balconies with double-glazed windows.

Following the success of the project, there are now plans for British Gas, in partnership with Southampton City Council, to renovate a further six towers in the city.