Warm Homes Nest scheme: annual report 2025 to 2026

This report uses installation data provided by the delivery agent, British Gas (part of the Centrica plc group), and advice service data provided by the Energy Saving Trust (EST). Both datasets cover the period from 1 April 2025 to 31 March 2026.

Headline achievements

• Between April 2025 and March 2026, Nest gave tailored energy-saving advice to 11,113 households. 
• Between April 2025 and March 2026, Nest installed home energy efficiency improvements such as heating systems, boilers, insulation, solar panels and heat pumps in 1,436 homes, helping vulnerable households reduce energy costs. 
• A dedicated crisis route ensured urgent support for 962 of these vulnerable households without heating or hot water, providing rapid interventions to make homes warm and safe.
• Retrofit upgrades and crisis route installations cut household energy bills by about £573 and £605 a year respectively and are projected to save over 6,607 and 22,000 tonnes of carbon over their lifetime respectively, showing big financial and environmental benefits.
• Complaints during the period April 2025 and March 2026 accounted for less than 1% of the 1,436 home energy efficiency upgrades, indicating very high satisfaction. 
• The scheme offered support for off-grid households, addressing the higher costs associated with traditional electric, oil, or solid fuel heating systems.
• The independent advice service guaranteed impartial guidance and consistently high standards of delivery and was available to all.
• Robust quality assurance and audit processes were embedded throughout the scheme, ensuring compliance with technical standards, safeguarding public funds, and driving continuous improvement in service delivery.

Profile of the 1,436 recipients receiving home energy improvement packages delivered between April 2025 and March 2026  

• Just over a third of household recipients receiving improvements were older, with the head of household aged 65 or above in 36% of cases, including 21% aged 75 and over.
• Most installations were in owner‑occupied homes, accounting for 80% of cases, with 14% in private rented homes and 6% in homes where the tenure was recorded as unknown (either owner‑occupied or private rented).
• 12% of households supported were relying on traditional electric, oil, or solid fuel heating systems, which are typically more expensive to run.
• The most common property types were mid-terrace and semi-detached homes, together representing over 62% of all installations. This broadly reflects the stock profile for Wales.

Energy efficiency impact of the 1,436 home energy improvement packages delivered between April 2025 and March 2026 

• Before improvements, energy efficiency was very low, with 49% of homes having an energy efficiency rating of F or G, indicating poor insulation and high heating costs.
• At the time the data was provided, 765 homes had a recorded energy efficiency rating following installation. Over 64% of these achieved an energy efficiency rating of C or higher, indicating a significant improvement in energy performance.
• Less than 1% remained at the lowest rating of F or G after interventions, demonstrating the transformational impact of Nest upgrades on household energy efficiency.

Customer analysis and data insights, developed since the first iteration of Nest began in 2011, were used to inform engagement and outreach, to ensure appropriate communication reached the customers most in need.

This included:

• promotion of the Nest website with 52,307 users between April 2025 to March 2026.
• a direct mail campaign which reached 35,609 vulnerable households in Wales.
• an online advice quiz that was completed by 1,791 households.
• paid Facebook and Google adverts targeted at eligible customers throughout Wales.
• supporting health boards, charities and community organisations across Wales to reach households who may benefit from our advice and support. 

Every customer who called the Nest helpline received tailored advice and support from the advice team to ensure they received the most appropriate help to match their specific needs. This included energy saving and water efficiency advice, a package of free home energy efficiency improvements for eligible customers, and signposting and referrals to a range of support services. 

Between April 2025 and March 2026, Nest supported 11,113 households with tailored advice and assistance. The highest number of households helped, 969, lived in Rhondda Cynon Taf, followed by Carmarthenshire with 909. 

Figure 1: number of households who received Nest advice and support by local authority, April 2025 to March 2026 

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Description of figure 1: Bar chart showing the number of households who received Nest advice and support within each local authority. 

Source: Nest management reports 

Third party support

Nest referred households to other organisations to provide further support where appropriate. A household can have multiple referrals; there were a total of 909 referrals. 

Figure 2: type of third-party referrals made, April 2025 to March 2026 

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Description of figure 2: Pie chart showing the proportion of each type of third-party referral made, based on all 909 referrals.

Source: Nest management reports

Benefit Entitlement Check (506 referrals, 56%)

Around 56% of referrals were for a benefit entitlement check. This ensures households are receiving all the financial support they are eligible for, helping to improve affordability and reduce fuel poverty. 

Priority Service Registered (224 referrals, 25%)

Almost half of all referrals were to the National Grid Priority Services Register. This service helps vulnerable customers by offering extra support from energy suppliers and national grid, such as advance notice of power cuts and priority assistance during emergencies.

Care and Repair (176 referrals, 19%)

Five percent of referrals were to Care and Repair, which provides practical help for older or disabled people to maintain and adapt their homes, supporting independent living.

Fuel Bank Vouchers (3 referrals, less than 1%)

A small number of referrals (<1%) were delivered through the Fuel Bank Foundation, which provide emergency credit for prepayment meters to help households in crisis.

The Nest scheme helped households in fuel poverty by reducing energy bills through free energy efficiency improvements to their home.

Customers who contacted Nest for advice and support were assessed for their eligibility to receive a package of free home energy efficiency improvements. 

The criteria for home improvements were: 

• A household member was in receipt of a means-tested benefit or the household met a low-income threshold, and the property was privately owned or rented with an indicative energy rating of E, F or G; or
• A household member was living with a qualifying health condition (in a D, E, F, G rated privately owned or rented property) and was in receipt of a means-tested benefit or an income below defined thresholds.

The Nest scheme includes a separate route for people with specific health conditions who are on low incomes. To be eligible, a home must have an EPC rating of D or lower (SAP score 68 or lower), and someone in the household must have a qualifying health condition.  Health conditions include a respiratory disease (respiratory infections, broncho-constriction in asthma, and chronic obstructive pulmonary disease), circulatory disease (including cardio-vascular disease, strokes and heart attacks) mental health (including depression, anxiety, psychosis and bipolar disorders) dementia intellectual and development disorders. More detail can be found in the Nest eligibility criteria.

Between April 2025 and March 2026, 4,142 households in Wales were assessed under the health route. Of these, 1,070 met both the health and home criteria and were referred for an income assessment. A total of 800 households then passed the income assessment and qualified for support.

Most households assessed included older adults, with 57% having at least one person aged 60 or over. Many properties were energy inefficient, with 48% rated E, F or G. Household incomes were generally low, with 46% earning less than 80% of the income threshold.

Figure 3: household referrals for an income assessment under the health criteria, by vulnerable household category, April 2025 to March 2026 [Note 1] [Note 2]

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Description of figure 3: Bar chart showing the percentage of household referrals under the health criteria, by vulnerable household category.

Source: Nest management reports

[Note 1] The Nest eligibility criteria provides a detailed breakdown of the health criteria and income thresholds 

[Note 2] A household referred for an income assessment under the health criteria may fall into more than one vulnerable household category.

As part of delivering support to tenants in privately rented homes, Nest worked in partnership with Rent Smart Wales to ensure private landlords were officially registered before improvements were carried out in their properties.

For each customer referred from the advice service, a fully qualified assessor:

• visited the customer’s home to complete a whole house assessment;
• identified technical potential and constraints to installing energy efficiency, renewable energy and low carbon heating measures in the property; and
• confirmed the eligibility of the customer.

The technical information was then used by independent experts to develop recommendations on the specific measure or combination of measures which are suitable and cost-effective for each individual property. 

The Nest team ensured all required permissions and consents (landlords, planning etc.) and third-party requirements (gas connections, asbestos removal etc.) were completed prior to agreeing the installation dates with the customer.

A network of Wales-based installers provided the installation services under the management of the Nest team. An inspection was undertaken of the completed installation package and remedial work of any identified defects was completed quickly and effectively.

Nest home energy efficiency improvement packages were designed for individual properties, so there was no standard package of measures, but it could have included a new boiler, central heating system, or loft insulation and some may have included newer technologies like solar panels, air source heat pumps and external wall insulation.

Between April 2025 to March 2026, most energy efficiency installations were heating systems (boiler replacements or LPG water heaters), accounting for around 31% of all measures. Solar and other renewable energy measures made up 37% of installations. An Air Source Heat Pump and associated hot water cylinder were much less common, representing less than 1% of all installations.

Figure 4: Nest installations by types of measure, April 2025 to March 2026 

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Description of figure 1: Pie chart showing the proportion of Nest installations by type of measure.

Source: Nest management reports 

Between April 2025 to March 2026, Nest provided 1,436 energy improvement package installations. The highest number of installations were in Rhondda Cynon Taf with 164, followed by Swansea with 130. 

Figure 5: home energy improvement packages by local authority, April 2025 to March 2026 

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Description of figure 5: Bar chart showing the number of home energy improvement packages by local authority provided through Nest by local authority.

Source: Nest management reports 

This section provides a summary of households who received Nest home energy efficiency improvement packages between April 2025 and March 2026, broken down by household characteristics. Information on households who received advice is provided earlier in the report. Detailed visualisations are represented on our interactive dashboard and published tables.

Fuel poverty profile

Nest aims to bring people out of fuel poverty. During the initial application process, householders were asked to confirm their household income. This information was assessed against modelled running costs for their household. This allowed the Nest advice team to assess whether the customer was living in fuel poverty.

Households who were assessed to be spending over 10% of their income on energy bills were classified as living in fuel poverty, with households spending over 20% classed as living in severe fuel poverty.

More than three quarters of households receiving a home energy efficiency improvement package self-reported being in fuel poverty or severe fuel poverty. Around 32% said they were in fuel poverty, while 46% were in severe fuel poverty. The remaining 14% did not report themselves as being in fuel poverty and 8% did not provide information.

These figures are based on self‑reported status and do not necessarily reflect eligibility for the scheme, which is determined through broader criteria. As such, the proportion reporting they are not in fuel poverty should not be interpreted as evidence of mis‑targeting. 

Age profile of Household Reference person (HRP)

The Household Reference Person (HRP) is the person in whose name the property is owned or rented. If the property is jointly owned or rented, the HRP is the person with the highest income. If incomes are the same, the eldest person is chosen.

Households with an HRP aged 65 or over made up 36% of households receiving a home energy improvement package through the Nest scheme. A further 20% of households receiving improvements had an HRP aged 55 to 64. In contrast, only around 11% of households receiving improvements had an HRP aged 16 to 34.

Tenure

Most households receiving a home energy efficiency improvement package through the Nest scheme were owner-occupiers. Around 80% of recipients owned their homes, 14% were in private rented accommodation, and 6% were recorded as unknown (either owner‑occupied or private rented). The Nest scheme did not fund social housing upgrades as there is separate Welsh Government funding for that purpose. 

Net income

Households receiving a home energy efficiency improvement package generally had low incomes. Around 49% reported a net annual income below £15,000 for all household members combined, while 33% earned between £15,000 and £25,000. Only 18% had incomes above £25,000.

Protected characteristics

Information on protected characteristics such as ethnic group and disability status was collected. However, there were too many unknown or missing responses to allow meaningful analysis or reporting of these data. We will review and strengthen our data collection processes in future years to improve completeness and support more robust analysis of protected characteristics data.

This section provides a summary of households who received Nest home energy efficiency improvement packages between April 2025 to March 2026, broken down by the characteristics of their homes. Information on households who received advice is provided earlier in the report. Detailed visualisations are represented on our interactive dashboard and published tables.

Property type

Mid-terraced and semi-detached properties were the most common property types among households receiving a home energy efficiency improvement package, accounting for 32% and 30% of recipients respectively. End-terraced properties accounted for 12% of recipients, and bungalows also accounted for 12%.  Detached properties accounted for 11% of recipients. Flats accounted for 2% of recipients. These proportions reflect the characteristics of the homes receiving improvements and do not reflect the proportions in the housing stock as a whole.

Number of bedrooms

Smaller homes were more likely to receive a home energy efficiency improvement package. Almost half (49%) of recipients lived in homes with two bedrooms or fewer, while 41% were in three-bedroom homes. Only 10% lived in properties with four or more bedrooms.  This pattern reflects the fact that smaller, lower‑cost homes are more commonly occupied by lower‑income or single‑income households, who are at greater risk of fuel poverty, rather than the size of the home itself being a driver of fuel poverty. 

Age of property

Older homes were more likely to receive energy efficiency upgrades. Around 44% of supported properties were built before 1930, 10% between 1930 and 1949, and 21% between 1950 and 1966. A further 15% were built between 1967 and 1982, while only 10% were constructed after 1982. The lack of modern insulation and efficient heating systems in many older homes increases the need for improvements.

Main heating system and fuel type

Most households receiving a home energy efficiency improvement package had a boiler as their main heating system (93%). 88% of households used mains gas as their main fuel type. 

Central heating systems included: boiler systems with radiators, warm air and other systems such as underfloor heating, and communal systems. 

Gas connection

Most households receiving a home energy efficiency improvement package lived in houses connected to mains gas (88%). Homes without a gas connection often rely on alternative fuels, such as oil or LPG, which can be more expensive and less efficient. 

Wall type and insulation

Between April 2025 and March 2026, around half (47%) of homes that received a home energy efficiency improvement package had cavity walls. A further 42% had solid walls, 4% had an unknown wall type, 4% had system-built walls, and 3% had insulated solid walls.

Location: urban or rural classification

For Nest reporting purposes, local authority areas are grouped into two categories based on a classification established by the Welsh Government at the start of the Nest 2 scheme in 2018.

Urban: All local authority areas excluding Anglesey, Ceredigion, Gwynedd, Pembrokeshire and Powys. 

Rural: Anglesey, Ceredigion, Gwynedd, Pembrokeshire and Powys.

This geographical grouping has been used consistently since the start of the Nest 2 scheme and provides the basis for all urban/rural analyses presented in this report.

86% of homes receiving improvements were in urban areas, while 14% were in rural areas.

Nest home energy efficiency improvements including retrofit upgrades and crisis route installations have delivered estimated energy bill savings averaging £573 and £605 per household per year respectively, making a real difference to fuel-poor households. 

Energy efficiency: SAP rating & EPC band

The Standard Assessment Procedure (SAP) is the UK Government’s method for assessing the energy efficiency of homes. It produces a score from 1 to 100, which is then grouped into Energy Performance Certificate (EPC) bands A to G, with band A representing the most energy efficient homes and band G the least energy efficient. The Reduced Data Standard Assessment Procedure (RdSAP) is a simplified version of SAP used to assess existing homes.

The Nest scheme uses RdSAP to calculate a home’s SAP score before and after energy‑efficiency measures are installed. This helps assess whether the proposed measures can cost‑effectively improve the energy efficiency of the home. Nest typically supports homes in lower EPC bands G to D, which correspond to SAP scores from 0 to 68 and indicate poorer energy efficiency and higher running costs. After improvements have been installed, the SAP score is updated to reflect the measures actually fitted, as packages may change due to technical issues or customer preferences.

Changes in EPC band before and after installation of home energy efficiency improvement packages

Before improvements, most households had very low energy efficiency. Around 18% were in EPC band G, 31% were in band F and 20% were in band E. 

The change in EPC is primarily driven by the recommended installation measures. However, in some instances householders choose not to receive all measures offered, which impacts on the final EPC band. After installation, energy efficiency improved significantly.  

At the time the data was provided, out of 1,436 households supported, 765 of their homes had a recorded energy efficiency rating after installation. Almost two thirds (64%) of homes moved up to band C and above and 16% reached band B. Only 32% remained in band D, 4% in band E and less than 1% in band F and band G. 

Figure 6: Energy efficiency rating before and after installation of home energy efficiency improvement packages [Note 1]

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Description of figure 6: Bar chart showing the energy efficiency rating before and after installations of home energy efficiency improvement packages. 

Source: NEST management reports 

[Note 1] Data is based on home energy efficiency improvement packages delivered between April 2025 and March 2026. Out of 1,436 households supported, 765 of their homes have a recorded SAP score after installation. Post‑installation SAP scores were not available at the time the information was provided for 671 households.

Household savings: cost, energy and carbon dioxide emissions 

Data on household savings have been reported separately for the standard Nest scheme, where the PAS2035 process is followed from the start, a whole house assessment is carried out first and a full set of recommendations inform the energy efficiency improvement package.

Households referred through the crisis route require immediate support. Consequently, an emergency response is deployed to restore heating and hot water. Customers are subsequently offered an assessment for further energy efficiency measures and, if accepted, these are installed at a later date. 

Between April 2025 and March 2026, the average annual cost saving resulting from Nest installations across the standard Nest scheme and crisis route was £594, and the total lifetime CO₂ savings was 29,122 tonnes.   

During that period, home energy efficiency packages delivered through the standard Nest scheme were estimated to save households around £573 a year on energy bills, equivalent to about 85,946 megajoules of energy annually. The analysis also shows the expected lifetime reduction in carbon emissions for households receiving improvements, which total over 6,607 tonnes of CO₂.

Source: Nest management reports 

Description of Table 1: Breakdown of modelled energy savings per household receiving measures by local authority, with an estimated average saving of £573 per year or 85,946 megajoules (units of energy) per annum.

Between April 2025 and March 2026, home energy efficiency packages delivered through the crisis route were estimated to save households around £605 a year on energy bills, equivalent to about 21,208 megajoules of energy annually. The analysis also shows the expected lifetime reduction in carbon emissions for these households receiving improvements, which total over 22,515 tonnes of CO₂.

Source: Nest management reports 

Description of Table 2: Breakdown of modelled energy savings (crisis route) per household receiving measures by local authority, with an estimated average saving of £605 per year or 21,208 megajoules (units of energy) per annum.

Between April 2025 and March 2026, the Welsh Government invested £27.5m in delivering the Nest Scheme. To ensure value for public money, and to ensure the scheme’s support can reach as many people as possible, Nest has a threshold of £35k per household. Any project above this threshold requires additional assurance and sign-off before proceeding. The average spend per package of measures/home receiving support was highest in the Vale of Glamorgan at £17.7k, followed by Merthyr Tydfil at £16.5k. Gwynedd had the lowest average spend at £10.7k.  

Differences in average spend are determined by a range of property characteristics and specific constraints as well as household preferences. 

Figure 7: average spend per household on home energy efficiency improvements by local authority, April 2025 to March 2026 

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Description of figure 7: Bar chart showing the average spend per household on home energy efficiency improvements by local authority. Average spend varies between local authorities because different homes require different types of energy efficiency improvements.

Source: NEST management reports

An independent contractor is employed to quality assure the Nest scheme. The contractor reviews the work of the service on a risk basis, with a greater level of scrutiny applied to more complex and higher risk installations. The delivery agent has a target of 98% of installations achieving a first-time pass on inspection. This was surpassed, with 98.3% of installations achieving a first-time pass. 

Between April 2025 and March 2026, 1,436 home energy‑efficiency packages were installed. The percentage of customer complaints upheld during this period accounted for only 1.3% of all installations against a target of no more than 3% of upheld complaints, indicating very high satisfaction. 

Across all householders provided with advice or receiving energy efficiency improvements through the scheme, 5,217 postal surveys were issued to gather feedback on satisfaction with the service. One survey was sent per unique household and only where the household had agreed to the scheme’s Data Protection Agreement (DPA). Responses were monitored throughout each stage of the customer journey, with 880 householders answering the question on the overall service, of whom 92% reported being satisfied. 

As a separate exercise, British Gas measures customer satisfaction of the installations with the satisfaction rate for the period April 2025 to March 2026 being 96%. 

Testimonials

The Nest scheme continues to make a meaningful difference to households across Wales, helping customers to achieve warmer, more comfortable homes while improving energy efficiency and reducing reliance on costly or unreliable heating. The positive feedback received from customers demonstrates the real-life impact of the support provided through the scheme. Examples of customer feedback include:

The heat and warmth within our property now is stable. It's nice that we have cleaner, greener energy and no fluctuation of oil prices.

It was a godsend for us. After so long without reliable heating and hot water, having a warm home again has given us real peace of mind.

[The engineers] who went [to the property] were polite, did a good job and nothing was an issue for them. It was nice to see young men like that this day and age.

[The engineers] would not leave until they got the heating system running correctly and did not leave until 7pm. [The engineers] were very kind, efficient and all round lovely.

Visit NEST for more information about the Nest scheme, including how to contact the team.