Skip to main content


Flexible Residential Energy Efficiency Demand Optimisation and Management

Funding mechanismNetwork Innovation Allowance (NIA)
DurationOctober 2016 - January 2019
Estimated expenditure5.2 million
Research areaLow Carbon Technologies


The research objectives of this project are to better understand if hybrid heating systems are technically capable, affordable and attractive to customers as a way of heating homes. This project aims to investigate the feasibility of the use of heat pumps on both WPD’s & WWU’s network in order to:

  1. Demonstrate the ability of the hybrid heating system to switch between gas and electric load to provide fuel arbitrage and highly flexible demand response services; 
  2. Demonstrate the consumer, network, carbon and energy system benefits of deployment of hybrid heating systems with an aggregated demand response control system; and 
  3. Gain insights into the means of balancing the interests of the consumer, supplier, distribution and transmission network when seeking to derive value from the demand flexibility.



The Climate Change Act passed in 2008 committed the UK to reducing emissions by at least 80% in 2050 from 1990 levels. Meeting this target would likely require heat related emissions of CO2 from buildings to be near zero by 2050, both targets pose an enormous economic and environmental challenge to energy providers. In the recent past, the expectation from the government and others has been that gas networks would be switched off within the next 20-30 years, to be replaced by electrified heat. However, it is becoming clear that the electrification of heat brings with it many challenges – both technical and economic. It is imperative that the energy sector support research and invest in energy solutions that are affordable, reliable and safe for our customers.

In the UK, about 70% of all energy consumed is in the home, of which space heating and hot water production account for the bulk of the energy use. With the majority of the homes in the UK being heated by combustion of fossil fuels, a heat generating system that could improve domestic energy efficiency significantly has the potential to deliver dramatic reductions in primary energy consumption and CO2 emissions. 

Electricity is the most expensive fuel available in the UK, an energy savings trust report in 2013 found that rising costs for electricity hit poorer households with electric heating the hardest. Gas boilers typically emit 2-4 tons of carbon per year, depending on boiler and house type. Converting 10,000 homes to hybrid heating could save between 10,000 and 20,000 tonnes of carbon per year. The hybrid heating system has the potential to help meet the EU’s ambitious environmental targets of achieving a 20% cut in greenhouse gas emissions compared with 1990 levels and a 20% reduction in energy consumption by 2020. The technology, which combines domestic gas boiler and air-source heat pump heating, has the capability to use either fuel or both and can be used as fully flexible loads capable of providing significant energy system value. 


PassivSystems Limited and its partners have put together a proposal to deliver a technically and commercially successful innovation project to realise the benefits of using the hybrid heating system (heat pump and gas boiler) for our networks and our customers. The success of the work will depend largely on the location, housing types and type of heat pump. The trial will be conducted in domestic housing units in the Bridgend area to demonstrate potential solutions to the findings of earlier research projects such as Bridgend Future Modelling. A variety of liaison meetings between PassivSystems and the Local Authority as well as other interested organisations, to gain the support and ensure the deployment satisfies the given criteria, has been undertaken. 

The methodology for the delivery of this Project will follow the process below: 

  1. Selection of the area for the trial (customer engagement plan) 
  2. Selection of the type and size of the heat pump 
  3. Modelling 
  4. Mobilisation (procurement of equipment and services) 
  5. Trials or field test, including measurements (install equipment) 
  6. Connection agreements and policy 
  7. Analysis and close down (Analyse results, evaluate) 

  • The proposed project runs for 27 months and has been broken down into two phases, which are defined in 14 work packages. The research objective is to better understand how hybrid heating systems can be: 

    1. Affordable through using advanced algorithms to unlock value from energy markets; 
    2. Trustworthy by building consumer trust in new technology whilst providing the same level of comfort in people’s homes; and 
    3. Developing appropriate user interfaces and information systems to help drive adoption. 

    All design and foundation development activities conclude in the first six months. Pilot installations are initially undertaken in four households before installations are rolled out to the rest of the trial properties, followed by a period of monitoring and experimentation phase which seeks to learn and then iteratively refine the heating and load management processes and the consumer interface and information provision over a full year. 

    The full size and scale of the potential solution will only become apparent when trials are conducted. The FREEDOM project does not involve us offering or modelling the provision flexibility services to the System Operator or wider market by WPD or WWU. 

  • The research will document the outputs of the pilot installations, the system interfaces and customer feedback that will enable us to continue to the next steps towards a commercial solution. The project will: 

    1. Present a comprehensive review of the technology; 
    2. Produce a case study of how the technology contributes to the reduction of carbon emissions and compares with previous energy bills for domestic consumers through increased heating system efficiencies and a reduced unit cost; 
    3. Identify if the solution can bring benefits to WPD’s & WWU’s networks; 
    4. Deploy trials subscribed to by up to 75 participants; 
    5. Produce a proven architecture for the hybrid heating system; and
    6. Develop a business process (polices, standard techniques etc.) for the use of hybrid heating system. 
  • The project will deliver a hybrid heating system that is able to support the electricity and gas network in the discovery of sustainable alternatives to help deliver the UK’s energy requirements. The project will consider whether the technology can defer network investments, remove network constraints and provide a fully flexible domestic heating load management service. The control enhancements will move well beyond current hybrid technology that makes a simple switching decision based on fixed tariff information and will provide accurate load forecasts by fuel type by quarter hour to the energy supplier. Consumers will for the first time be able to see a forecast of spend on heating for the coming period, based on their individual home, occupancy patterns, weather forecast and comfort settings. Other network operators within both the gas and electricity sector will also be able to gain a comprehensive understanding of hybrid heat systems after reviewing this project’s reports and results. 

  • July 2018

    The launch for the Freedom final report is planned for the 9th of October in the House of Commons, Westminster.

    June 2018

    Following the FREEDOM Project expiry letter that was issued in May 2018, eight (8) homes wish to have either the Passiv controls removed or revert back to a standard combi-boiler. These include three (3) Wales & West Housing Association (WWHA) homes using the MasterTherm system, three (3) Samsung homes and one (1) Daikin home.

    May 2018

    We have now issued a contract expiry letter to all trial participants, detailing their heating control and hardware options. The participants have until 31st May to respond. Within the recent contract expiry letter, trial participants have been informed that no further experiments will take place; and we also updated them on decommissioning and next steps.

    January 2018

    Intense hybrid heating system experiments are currently being completed. This will result in more heat pump use. The project has released its final development of the project plan: Budgeting and aggregation. Gas Assessment and Training Ltd has continued to conduct independent assessments of all hybrid installations. Currently 37 assessments have taken place.

    November 2017

    The FREEDOM Project has completed all 75 installations; this includes the 4 pilot homes. The project is now developing the budgeting and system feedback mobile app functionality and the aggregated demand management platform in time for the January/February experiments.

    October 2017

    During the month of October most of the hybrid heating installations were completed. The total number of installed hybrid heating systems is now 74, from the required 75. The project is now developing the budgeting and system feedback mobile app functionality. The project is also looking at the interventions and experiments that may be used during the course of the project, starting off with a brief outline of the hybrid heating system control strategy already in use by PassivSystems. 

    August 2017

    During the month of August most of the activity was around recruitment and control development. The total number of installed hybrid heating systems to date is 23. However, the number of installations is likely to increase in the coming months due to increased recruitment activity.

    July 2017

    During the month of July most of the activity was around recruitment and control development. In the course of the month we installed 12 hybrid heating systems in Wales and West Housing properties. We also continue to receive interest from some WPD employees resident in Bridgend since sending out an email to the depot in the area.

    June 2017

    During the month of June most of the activity was around recruitment and control development. As part of the ongoing recruitment, we can now formally contact tenants about the FREEDOM project, starting with Wales and West Housing in June and Hafod Housing tenants in July. We have also received 5 private homeowner enquiries.

    April 2017

    During the month of April most of the activity was around gathering and analysing the data collected from the pilot installations. Also during this period there was significant progress in household recruitment for the main trial and continued collaboration with registered social landlords.

    February 2017

    PassivSystems have been conducting pilot trials in four households in the Bridgend area to test the technology of hybrid heat pumps as well as to verify the competency of the selected installers. PassivSystems engaged Daikin, Samsung and Thermal Earth in the pilot trial. PassivSystems has had written commitment from Hafod Housing that they could provide 44 homes for the project. The Wales and West Housing Association Board has approved the FREEDOM Project and will offer up to 150 homes.

    January 2017

    The decision on the Customer Engagement Plan was received from Ofgem on the 17th of January 2017. Following this decision PassivSystems will be conducting pilot trials in four households in February in the Bridgend area to test the technology of hybrid heat pumps as well as verify the competency of the selected installers. 

    December 2016

    We are awaiting a response following the submission of the Customer Engagement Plan to Ofgem. 

    PassivSystems have confirmed that Daikin, Samsung and Thermal Earth will be involved in the pilot trial. PassivSystems has had written commitment from Hafod Housing that they could provide 44 homes for the project. The Wales and West Housing Association Board has approved the FREEDOM Project and will offer up to 150 homes. The Valley to Coast Housing project team will be presenting the FREEDOM Project to their board in January.

    November 2016

    Customer Engagement Plan has been submitted to Ofgem. Out of the 12 Request For Information (RFI) that were sent to prospective suppliers of the heat pumps, 9 responses have been received. 4 suppliers were invited to PassivSystems HQ for further discussions. The outcomes of these discussions are yet to be communicated.