DESNZ: Find ways to save energy in your home
An online government tool that provides personalised recommendations for energy-saving improvements in homes in England and Wales.
1. Summary
1 - Name
Find ways to save energy in your home
2 - Description
It is an online government tool that provides personalised recommendations for energy-saving improvements in homes in England and Wales. By entering details about your property—such as house type, age, insulation, and window glazing—the tool analyses its energy efficiency and generates tailored suggestions.
It is used to help homeowners identify cost-effective ways to make their homes cheaper to heat and easier to keep warm. The tool estimates improvement costs, shows how much money could be saved on energy bills, and provides clear next steps for making each improvement.
3 - Website URL
https://www.gov.uk/improve-energy-efficiency
4 - Contact email
eligibilitycheckersupport-cai@energysecurity.gov.uk
Tier 2 - Owner and Responsibility
1.1 - Organisation or department
The Department for Energy Security and Net Zero
1.2 - Team
The Consumer Advice and Information Team
1.3 - Senior responsible owner
Deputy Director of Consumer, Advice and Information
1.4 - Third party involvement
Yes
1.4.1 - Third party
Softwire Technology Limited
1.4.2 - Companies House Number
03824658
1.4.3 - Third party role
A third-party supplier has been engaged to support the development, build, and deployment of the algorithmic tool. They were responsible for creating the technical solution, implementing the eligibility logic, and ensuring the service met the required performance and security standards. The same supplier now provides ongoing maintenance, support, and continuous improvement to ensure the tool remains accurate, reliable, and up to date.
1.4.4 - Procurement procedure type
The third-party supplier was contracted via a G-Cloud 14 framework call-off procedure, in line with government procurement guidelines.
1.4.5 - Third party data access terms
The third party is granted limited access to data strictly for the purposes of developing, maintaining, and supporting the service. Access is provided under contractual data protection obligations, with controls in place to ensure data is accessed only when necessary and handled in accordance with GDPR and departmental security requirements.
Tier 2 - Description and Rationale
2.1 - Detailed description
FWTS is a government digital advice service that helps households understand how they can reduce energy use and lower bills. It provides tailored guidance based on the user’s circumstances, signposting them to energy efficiency improvements, available schemes, and practical actions they can take at home.
- User enters the web site
- User enters information about their property
- User receives recommendations about potential energy saving measures for their home, such as installing solar panels or a heat pump. The site lists some estimates for the cost, estimated disruption, and estimated saving. The site provides links for further reading, though will not facilitate directly the installation of these energy saving measures.
- User can accept or reject these suggestions to build a more personalised action plan. The user can then download this action plan.
- User receives a unique recommendations code that they can use to view their recommendations again at any time.
2.2 - Benefits
Provides tailored information for a user for how they can reduce their energy consumption.
2.3 - Previous process
Simple Energy Advice (SEA) was the legacy website hosted off GOV.UK.
- User enters the web site
- User input address to pull up EPC data. Answer some behavioural & personal questions
- User creates customised energy saving plan. Download, email or share on Facebook
- User can accept or reject these suggestions to build a more personalised action plan. The user can then download this action plan.
- User is signposted to gov and LA financial support (depending on eligibility from personal questions)
- User is referred to qualified tradespeople
Website has linkages, e.g. to EPC open data so that it can pull property details, and to the Green Deal installer database. Website has a database of Local Authority energy efficiency schemes.
2.4 - Alternatives considered
N/A
Tier 2 - Deployment Context
3.1 - Integration into broader operational process
The information provided is advisory for users and does not form part of a larger process. The output of this tool is reviewed by the user that fills out the form. They can use a contact form to inform DESNZ if the information appears inaccurate
3.2 - Human review
The output of this tool is reviewed by the user that fills out the form. They can use a contact form to inform DESNZ if the information appears inaccurate.
3.3 - Frequency and scale of usage
Since release there have been around 2,000 interactions per month with the tool.
3.4 - Required training
N/A
3.5 - Appeals and review
No Formal Appeals Process: There is no formal appeals process for the advice or recommendations provided directly by the service.
If a member of the public wishes to challenge a decision about eligibility for a government scheme, they must follow the appeals process of the relevant scheme administrator. For issues with energy efficiency ratings (EPCs), there is a defined process involving the assessor and their accreditation body.
Feedback Mechanism: Members of the public can provide feedback on the service via a Microsoft form. This feedback is used to improve the service but does not constitute a formal appeals process.
Tier 2 - Tool Specification
4.1.1 - System architecture
The application is written in the programming language C# utilising the ASP.NET library. The code is deployed using Docker to Fargate servers hosted in the UK. This is managed via AWS ECS. The public referral entry portal and private Local Authority portal are kept separate. User authentication is managed with AWS Cognito. The code is available at: https://github.com/UKGovernmentBEIS/beis-simple-energy-advice-beta
4.1.2 - System-level input
Information about the user’s property including - Wall type - Address - Property age We also take a contact email and request an EPC for the property address.
4.1.3 - System-level output
Energy saving recommendations for the user’s property, such as Cavity wall insulation or Solar panels.
4.1.4 - Maintenance
Support work completed ad-hoc in response to issues.
4.1.5 - Models
BRE SEA (Simple Energy Advice) API dwelling energy calculator.
Tier 2 - Model Specification
4.2.1. - Model name
BRE SEA (Simple Energy Advice) API dwelling energy calculator.
4.2.2 - Model version
version 2
4.2.3 - Model task
Calculate energy use for a dwelling, along with cost and carbon data. In addition, results for potential energy saving measures.
4.2.4 - Model input
Dwelling and occupancy information, such as construction date, property type, heating system, dwelling fabric, thermostat setting and number of occupants.
4.2.5 - Model output
Dwelling savings from improvement measures for energy, cost and carbon along with estimated measure lifetime and range for installation costs.
4.2.6 - Model architecture
SEA is an energy saving calculator. 1. Inference is applied to user inputs and OpenEPC data to expand data to run an energy model. 1. RdSAP and OA (occupancy assessment) rule sets are also applied to further expand the data set and generate potential energy saving measure scenarios. 1. A SAP energy calculation is run to calculate the dwelling energy use, cost and carbon. Along with the potential savings from improvement measure package. 1. Details of the methodology for energy modelling using SAP, RdSAP and OA are published here: https://bregroup.com/expertise/energy/sap/standard-assessment-procedure-2012
4.2.7 - Model performance
The performance of the “Find Ways to Save Energy in Your Home” model and service was evaluated using a combination of quantitative KPIs and qualitative user feedback. This approach ensures a comprehensive understanding of how well the model meets user needs and organisational objectives.
Validation and Testing
User-Centred Design: The SEA service was developed using Agile methods, with continuous collaboration between BEIS, Energy Saving Trust, and delivery partners. User research was embedded throughout, including remote, moderated usability testing and interviews with participants from a range of backgrounds, ages, and digital skills.
Iterative Improvement: Insights from user testing directly informed design changes. For example, feedback led to clearer explanations of what users would need before starting, improved flows for returning users, and more accessible content for those with additional needs.
Performance Analytics: Quantitative data, such as completion rates and user satisfaction, were monitored throughout the Beta phase to track engagement and identify areas for improvement.
Supporting Evidence User Research: Two rounds of usability testing were conducted with participants representing a range of ages, incomes, and accessibility needs. Insights from these sessions shaped the service’s design and content.
Analytics: Ongoing monitoring of user journeys and feedback forms provided quantitative evidence of engagement and satisfaction.
Continuous Learning: The Beta phase established a foundation for ongoing improvement, with a backlog of future enhancements identified based on user needs and feedback.
Fairness, Security, and Privacy
Fairness: User feedback is monitored for evidence of bias or exclusion. Several users noted that the service did not always account for specific property types (e.g., listed buildings, flats, or homes with existing measures), suggesting areas for improvement in inclusivity.
Privacy: No personal or financial information is required to use the service, and user data is anonymised in all feedback and reporting, in line with GDPR and government standards.
4.2.8 - Datasets and their purposes
The Find Ways to Save Energy in Your Home (FWTS) service does not use machine learning or artificial intelligence models. Instead, it is built on a rule-based decision engine that applies government-defined eligibility criteria and energy-saving recommendations.
Model Type: Rule-based logic: The service uses deterministic rules rather than predictive or statistical modelling. These rules are based on official energy efficiency standards and policy requirements.
Purpose: To provide tailored energy-saving advice for households based on property characteristics and user inputs.
Data Sources: Property and Energy Data: Information such as property type, heating system, and insulation status provided by users. Energy Performance Certificate (EPC) Data: Accessed through integration with the EPC register to support accurate recommendations. Fuel Price Data: Used to calculate potential cost savings for recommended measures. Government-defined criteria: Ensures recommendations align with policy objectives.
How Data Is Used: All data is used for real-time calculations and applying predefined rules to generate personalised advice. No datasets are used for training, validation, or fine-tuning, as the service does not employ machine learning or foundation models.
Transparency: All recommendations are based on published eligibility criteria and calculation rules. No automated decision-making beyond applying these predefined rules.
2.4.3. Development Data
4.3.1 - Development data description
The datasets used for developing and evaluating the service include anonymised user journey data, aggregated feedback from voluntary user surveys, and performance analytics collected during the Beta phase. No personal or financial data is stored or processed.
4.3.2 - Data modality
The primary data types are tabular (user journey analytics, survey responses) and text (open-ended feedback). No image, audio, or geospatial data is used.
4.3.3 - Data quantities
During public Beta, a significant volume of user journeys was recorded, alongside thousands of survey responses analysed for feedback and satisfaction. Data was segmented for analysis by user type and journey stage.
4.3.4 - Sensitive attributes
N/A. No personal or protected characteristics are collected or processed. All data is anonymised
4.3.5 - Data completeness and representativeness
Data covers a broad range of users, including different ages, incomes, and accessibility needs. Efforts were made to ensure representativeness, but some groups (e.g., non-homeowners) were out of scope for. Missing data was minimised through voluntary survey design.
4.3.6 - Data cleaning
N/A
4.3.7 - Data collection
Data was collected through the live Beta service and voluntary user surveys, with clear consent and privacy information provided to all participants. The data was collected solely for the purpose of improving the service and monitoring performance.
4.3.8 - Data access and storage
All data used by the ‘Find Ways To Save Energy In Your Home’ service is stored securely in line with UK government standards and data protection legislation. No personal or financial data is retained by the service. Access to development and operational data is restricted to authorised project team members and approved users, as defined in the Memorandum of Understanding (MoU) with the Department for Levelling Up, Housing and Communities (DLUHC). Data is stored on secure servers, with daily overnight backups in place. Data is not transferred or disclosed outside the European Economic Area (EEA). Data is deleted after a defined retention period or upon termination of the permitted purpose, in accordance with the MoU and government policy.
4.3.9 - Data sharing agreements
A formal Memorandum of Understanding (MoU) exists between the Department for Energy, Security and Net Zero (DESNZ) and the Department for Levelling Up, Housing and Communities (DLUHC) for the sharing of Energy Performance Certificate (EPC) data. This agreement enables DESNZ to access specific EPC data variables for the operational activities of the ‘Find Ways To Save Energy In Your Home’ digital platform. The MoU sets out the permitted purpose, data protection requirements, security measures, and review/termination procedures. Data is not shared outside the EEA or with third parties without equivalent protection.
Tier 2 - Operational Data Specification
4.4.1 - Data sources
User inputs for their information, EPC API will find their EPC based on first line of address and postcode.
4.4.2 - Sensitive attributes
We store: - Property information - Property recommendation These are not stored with identifiable property information which makes this data non sensitive.
4.4.3 - Data processing methods
N/A
4.4.4 - Data access and storage
User interaction logs are stored for 30 days. Collected information is stored for the lifetime of the service. This data can only be accessed by users that know their recommendations code. Sensitive data is not stored.
4.4.5 - Data sharing agreements
A formal Memorandum of Understanding (MoU) exists between the Department for Energy, Security and Net Zero (DESNZ) and the Department for Levelling Up, Housing and Communities (DLUHC) for the sharing of Energy Performance Certificate (EPC) data. This agreement enables DESNZ to access specific EPC data variables for the operational activities of the ‘Find Ways To Save Energy In Your Home’ digital platform. The MoU sets out the permitted purpose, data protection requirements, security measures, and review/termination procedures. Data is not shared outside the EEA or with third parties without equivalent protection.
Tier 2 - Risks, Mitigations and Impact Assessments
5.1 - Impact assessments
N/A
5.2 - Risks and mitigations
The tool needs to store recommendation history long term so that users can always retrieve this. This means the database must store a large amount of information. The information is not personally identifiable, though should be treated securely regardless. This is mitigated by showing recommendations only to those that have a particular code, and restricting full database access to few individuals with security clearance.