Homes for Net Zero (HfNZ) is a multi-year, longitudinal research programme which is being delivered by Energy Systems Catapult’s Living Lab for the Department for Energy Security and Net Zero (DESNZ).

The Catapult was appointed to deliver Phases 1 and 2 of the project which started in September 2023 and will run until Autumn 2026.

HfNZ was commissioned by DESNZ to improve their evidence base on the options for homeowners to transition to a home that is compatible with Net Zero policy. We are carrying out practical research and monitoring 1,250 real homes that are recognised as challenging to decarbonise.

The aims of Phases 1 and 2 of the project are to:

• Develop a flexible home monitoring trial to explore a range of research priorities
• Better understand the opportunities and barriers for homeowners to transition to a Net Zero-ready home
• Explore the role of alternative electric heating technologies to decarbonise heating in homes
• Explore the emerging issues and potential solutions of adapting homes to a changing climate.

The programme consists of two cohorts of trial participants who are supporting us to test practical interventions, alternative heating technologies, and consumer experiences in their homes:

• Trial 1 focuses on low-cost retrofit measures in hard-to-decarbonise solid wall homes
• Trial 2 explores the use of reversible air-to-air heat pumps (RAAHP) in electrically heated homes and monitors the performance of pre-installed heat batteries.

Together, these projects aim to generate robust evidence to inform future policy and consumer propositions.

The challenge

The UK’s transition to Net Zero requires householders to adopt low-carbon heating and energy efficiency measures. However, DESNZ recognises that many homes are challenging to decarbonise from a policy perspective.

Challenges include up-front cost, disruption, compatibility with existing systems, and consumer awareness. HfNZ is building the real-world evidence to address these issues by understanding:

• Which retrofit measures deliver meaningful energy savings and support the transition to decarbonised heating;
• How consumers respond to new heating technologies;
• The lived experiences of households using heat pumps and heat batteries.

Without this evidence, policy risks being shaped by assumptions rather than real-world insight. The programme was designed to fill these gaps and support DESNZ’s strategic goal: making it easy and desirable for people to decarbonise their homes.

The solution

The Catapult is using its Living Lab – a real-world data and trials facility connected to more than 5,000 diverse homes across the UK.

Through large-scale monitoring of domestic energy, the Living Lab allows organisations such as DESNZ to understand changing energy demand and opportunities for interventions such as retrofit and alternative heating technologies, as well as understand householder perspectives. On this trial, our Living Lab digital infrastructure is collecting smart meter, temperature, humidity, air quality and heat meter data from homes, with over two billion data points collected to date.

HfNZ is being delivered through two distinct research trials:

Trial 1: Hard-to-decarbonise homes

In Phase 1, the Catapult in partnership with E.ON recruited 1,000 owner-occupied, gas-heated homes with solid walls to understand their readiness for decarbonised heating.

These homes received interventions from E.ON such as new loft insulation, draught proofing, and heating system MOTs. Smart monitoring equipment was installed, including tado° temperature sensors, air quality monitors and heat meters.

Personalised retrofit roadmaps were developed for 100 homes, supported by PAS 2035 surveys and SAP assessments. An additional 100 homes received simple behavioural tips to reduce their energy use and bills.

Trial 2: Reversible air-to-air heat pump and heat battery monitoring trial

In Phase 2, we recruited 200 smaller owner-occupied homes that already had electric heating to avoid the disruption of removing their wet heating systems.

From these, 30 reversible air-to-air heat pumps were installed by our installation partner Robert Heath which included a mix of single-split, multi-split, and multi-plus systems.

Monitoring includes collecting data from smart meters, temperature sensors and air quality devices. We carried out consumer surveys and interviews to understand lived experience, ease of use and comfort levels. We developed bespoke roadmaps for 50 homes to help homeowners understand their path to decarbonisation.

The Catapult are also monitoring 50 homes with heat batteries pre-installed via OEM partners Tepeo and Sunamp. Historic and ongoing performance data is being analysed, alongside smart meter and temperature monitoring. Consumer insights are being gathered through 50 surveys and 15 interviews. The trial focuses on consumer experiences, efficiency, effectiveness, and operational costs.

The impact

The HfNZ programme is building a comprehensive evidence base across two key areas of home decarbonisation:

• Trial 1: delivered more than £600,000 worth of retrofit measures to over 280 homes, improving comfort, energy efficiency and readiness for decarbonised heating systems.
• Trial 2: 30 homes received reversible air-to-air heat pumps and we are collecting monitoring data from a further 165 homes to assess performance, cost, and consumer appeal. It’s also helping DESNZ to fully understand the participant journey for reversible air-to-air heat pumps, from design, planning, property ownership challenges to installation and commissioning. This trial is also providing data to support the analysis of in-situ heat batteries to understand their real-world performance.

The data from the trials is being analysed by the Catapult and University College London to answer DESNZ’s research questions on energy savings, technology suitability, consumer preferences and climate resilience. Work is ongoing and the findings will be published in three formal reports covering:

• Winter 2024/25: based on initial analysis of winter 2024/2025 data, roadmap feedback, along with pre intervention consumer insights.
• Summer 2025: based on initial analysis of Summer 2025 data, counterfactual analysis, cooling performance and air quality insights.
• Winter 2025/26: based on initial analysis of winter 2024/2025 data, final analysis of heating performance, consumer experience, and Net Zero readiness.

HfNZ is shaping the future of low-carbon living in the UK. To learn more or explore partnership opportunities, email: homes@es.catapult.org.uk