A New Standard for Energy Efficiency in Central Dublin

A LEED Platinum-rated office building in central Dublin, serving as the European HQ for social media giant Twitter.

Hibernia REGL
Twitter (European HQ)
Dublin, Ireland
Project overview

Hibernia REGL is a major Irish property group with a €1.5 billion portfolio primarily comprising high-quality offices in central Dublin.

Despite 1 Cumberland Place earning LEED Platinum status in 2018, Hibernia REGL, and their tenant, Twitter, partnered with Symphony Energy in 2022 to identify energy inefficiencies and create saving opportunities in the 11,984 sq.m office building.


1 Cumberland Place was already a highly energy efficient building to begin with, having achieved LEED Platinum status in 2018 when the building underwent total refurbishment. Symphony Energy’s challenge was to take its performance to a next generation standard, achieving radical reductions in both gas and HVAC electricity demand without compromising on comfort. We did this by implementing our Smart Optimisation solution over the course of 5-months.

Key stats
HVAC Gas Savings
HVAC Electricity Savings
4.75 YEARS

Our process

Mapping & Learning

The project began with an extensive review of the building physics, HVAC design and installation along with monitoring various BMS (Building Management System), weather forecasting and IoT data points via a Loytec LINX automation server.

In order to add even more data to the picture we introduced 119 Symphony Welltech smart sensor-controllers that could monitor the IEQ (Indoor Environmental Quality) of individual spaces throughout the building.

This is the first project in which we introduced Symphony Welltech as part of our toolkit. Designed in-house by our Head of Product, it is significantly more advanced than any comparable product on the market. Symphony Welltech is capable of monitoring up to 10 key metrics including CO2, occupancy, and temperature. In addition to providing real-time insights into ventilation requirements, it can control the local plant tasked to deliver the specified air quality while exchanging key data with the BMS.

This mapping and learning exercise revealed the environmental signature of the building from which a virtual model could be created in Symphony Cloud, our building energy management platform. This virtual model accurately represented the operation of 1 Cumberland Place, capturing key aspects of its energy dynamics and performance.


Within a controlled sandbox environment, we employed custom performance algorithms to conduct comprehensive simulations, evaluating the response of the building's energy systems under various demands and conditions.

This iterative process allowed us to test different strategies, configurations and scenarios providing valuable insights into the performance of the building. Through rigorous assessment we were able to identify targeted opportunities for optimisation that would enhance the building's energy performance.

The deployment of Symphony Welltech while mapping the building allowed us to model for highly-efficient demand ventilation due to its superior localised demand control capabilities. Additionally, the chilled water cooling system at 1 Cumberland Place, makes it suitable for the implementation of Symphony Cycle, our patented waste heat recycling process which is capable of up to 30% HVAC energy savings on its own.

These proprietary elements of our optimisation toolkit were invaluable in creating energy efficiencies in an already highly-efficient building. Over a period of several months, we fine-tuned the operational settings to always use the least amount of energy while maintaining comfort levels.


The next step was to align the virtual model of 1 Cumberland Place with the real building so that the optimised operational settings could be introduced. With the Loytec LINX automation server acting as an additional brain for the BMS, the new settings were deployed from Symphony Cloud and began to run in place of the prior function of the BMS.

This simple process of alignment allowed us to seamlessly transform the HVAC energy performance of the building and immediately reduce its energy usage. Our custom algorithms now continuously predict, monitor, and respond to real-time fluctuations in energy demand while delivering newly optimised HVAC performance.

Symphony Welltech is now focusing ventilation control by operating at a highly localised level, effectively managing the airflow within the building as a collection of micro-environments. Fresh air supply precisely follows the demand as occupants transition from one area to another. As a result, the AHU (Air Handling Unit) plant can reduce its output, optimising energy consumption.

Even with reduced airflow in some areas, Symphony Welltech is delivering more than the originally designed quantity of air to spaces that require it. This dynamic approach guarantees that each individual area of 1 Cumberland Place receives superior Indoor Environmental Quality (IEQ) levels, surpassing the design expectations while achieving significant energy efficiencies.

Symphony Cycle is in operation recycling waste heat into usable heat while generating free cooling for the building. This process transfers the heated chilled water returning from the fan coil units, into the AHU cooling coils. These coils use the cool outside air to remove heat from the warmed chilled water so this water can return to the fan coils to collect more heat from rooms with surplus heat. By cooling the chilled water in the AHU cooling coils, the incoming fresh air is heated. This in turn has the effect of mostly eliminating the need for any heating of the air by the heating system AHU heating coils.


All the relevant BMS data, new Symphony WellTech data and externally sourced IoT data is merged onto our Symphony Cloud platform. This provides key personnel with insights into the operation of the building and intervention tools for additional control.

Custom performance algorithms apply formulas across various fields and IoT data to form virtual data points that automatically optimise the control of the HVAC plant and provide unique insights into small but high impact operational nuances. Our algorithms are continuously learning and adapting to both seasonal forecast data and changing conditions within the building, allowing for automated, dynamic and responsive energy management at 1 Cumberland Place.

Symphony Cloud provides a single point of truth platform that can be merged with energy metering and other data sources. By hosting the BMS and the insightful associated virtual data, this cloud platform is equipped for reporting key metrics to its own and other ESG reporting tools.

Our Results


1 Cumberland Place was already a high-efficient LEED Platinum rated building; our solution took its performance to a next generation standard.

The total building gas consumption was reduced by 69%. The HVAC portion was reduced to the order of 76% when the hot water services and cooking gas were factored out. The domestic hot water is generated by an independent system that was not included in our solution.

The total landlord electricity consumption was reduced by 63%. The HVAC portion was reduced to the order of 75%.

For 87% of the 2,946 scheduled hours of operation post implementation, Symphony Cycle supported the full cooling load of the building for free. We estimate that Symphony Cycle alone is responsible for 30% of the total energy savings.

The central HVAC energy intensity during the 12-month savings and verification was 44 kWh/sqm/yr. This represents an unprecedented energy performance for a gas heated, air-conditioned office building in Ireland.

With the successful completion of this project, 1 Cumberland Place has now exceeded its 2035 Paris Proof Interim Target energy consumption of 55 kWh/sqm/yr. By replacing the current boiler system with an energy-efficient heat pump in the near future, the building is set to achieve its full 2050 Paris Proof Target of 30 kWh/sqm/yr.

These results were delivered within a guaranteed payback of 4.75 years

384,940 kWh
Electricity Savings
792,092 kWh
Gas Savings
295 tonnes
Carbon Savings
44 kWh/sqm/yr
Energy usage intensity

Projects Insights

Dynamic Demand Ventilation

The use of localised dynamic demand ventilation via smart sensor-controllers means that buildings can now be air-conditioned at a fraction of the cost of the current industry standards. This is particularly important in light of soon-to-be introduced standards for indoor air quality (IAQ) in the workplace.

Mechanical vs Natural Ventilation

Mechanical ventilation is now approaching the efficiencies of natural ventilation while providing greater control and air quality via filtration. This is particularly important in buildings located in densely populated areas where natural air quality is often compromised by nitrogen dioxide (NO2) from vehicles and particulate matter (PM) from nearby roadworks or construction.

Digital Optimisation for Retrofit

By adopting a digital optimisation approach, retrofitting existing buildings can deliver substantial benefits in terms of reducing operational carbon emissions, achieving greater efficiencies, and ensuring a better return on investment (RoI) compared to capital expenditure (CapEx) sustainability projects. One key advantage is that this approach eliminates the concerns associated with additional embodied carbon.

The Circular Economy

With lower energy consumption, the strain on HVAC equipment and other associated systems is significantly reduced. This results in decreased wear and tear, leading to fewer maintenance needs and lower associated costs. By optimising energy usage and reducing the workload on mechanical and electrical components, our solution helps extend the lifespan of the building's plant and equipment.

Chilled Water vs VRF

By implementing Symphony Cycle for waste heat recycling, Chilled Water Cooling (CWC) systems have become more efficient compared to Variable Refrigerant Flow (VRF) systems, while avoiding the environmental concerns associated with refrigerants.

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