Are you a landlord, housing provider or property professional planning for the next phase of energy-efficiency regulation? If so, the message is clear: retrofit compliance is becoming more evidence-led, more performance-focused and much harder to demonstrate through paperwork alone.

The government’s Warm Homes Plan sets out a major expansion of domestic retrofit, supported by £15 billion of public investment and a new Warm Homes Agency. It also confirms that private rented properties will need to meet EPC Band C across two metrics by October 2030, unless a valid exemption applies.

This is where Air Pressure Testing, thermal imaging and robust post-installation assurance become increasingly important.

However, there is an important distinction. As of September 2026, the published Warm Homes Plan does not create a universal legal requirement for every landlord to commission both tests. Instead, it establishes a much stronger expectation for documented quality assurance, property performance evidence, risk-based inspection and remediation. Under PAS 2035, air leakage testing may also be required by the project design, risk path, ventilation strategy or scheme conditions.

For landlords, the practical conclusion is simple: treat post-installation testing as an essential part of Warm Homes Agency compliance, not an optional afterthought.

What is changing under the Warm Homes Plan?

The Warm Homes Agency is being developed to coordinate home-upgrade delivery, improve consumer protection and support a more consistent approach to quality assurance. The proposed reforms are expected to be progressively implemented from 2028.

The direction of travel is unmistakable. Retrofit projects will increasingly be assessed against:

1. The quality and compliance of the installation
2. The performance of the building fabric
3. The efficiency of the heating or energy system
4. The quality of the evidence submitted
5. The property’s performance after installation

The government’s proposed consumer protection framework includes installer evidence, Retrofit Coordinator review, central recording of installation information, spot checks, targeted inspections and clear routes for remediation when work fails to meet the required standard.

This represents a shift away from “measure installed” towards “outcome achieved”.

That matters because a property can receive insulation, new windows or a heating upgrade and still perform poorly if the measures are badly designed, incorrectly installed or not properly integrated.

Why Air Pressure Testing matters for retrofit performance

Airtightness is one of the most overlooked elements of domestic retrofit.

A building envelope can appear well insulated while still losing substantial heat through gaps around:

• Windows and doors
• Loft hatches
• Service penetrations
• Floor and wall junctions
• Chimneys and flues
• Skirting boards
• Electrical outlets
• Insulation interfaces
• Roof and eaves details

These gaps create uncontrolled air movement. They can increase heat loss, reduce comfort and make it harder for a heating system to deliver the expected results.

This is particularly important when a property is being upgraded under a Whole House Retrofit approach. Fabric measures, ventilation and heating systems must work together. If the building is improved without understanding its existing air leakage, a landlord may invest significantly without achieving the intended energy savings.

A professional air pressure test can:

1. Establish a baseline before work begins
2. Identify significant leakage locations
3. Inform the retrofit design and ventilation strategy
4. Check whether airtightness measures have worked
5. Confirm that installation has not introduced unexpected leakage paths
6. Provide evidence for technical monitoring and project sign-off

Under PAS 2035, where fabric measures are proposed, the design should include an airtightness and air leakage testing strategy. Pre- and post-installation testing is strongly recommended for major insulation projects.

For certain higher-risk projects, testing becomes particularly important. CPH Retrofit’s Air Pressure Testing service explains how projects involving more than 30 properties, listed buildings, conservation areas or high-rise buildings may fall within higher-risk pathways requiring pre- and post-testing when lodged through TrustMark requirements.

Thermal imaging: optional test, essential insight

Thermal imaging is not currently a universal mandatory test for every Warm Homes Plan installation. Nevertheless, it is a powerful diagnostic and quality-control tool.

An infrared survey can reveal temperature variations across the building envelope that may not be visible during a standard visual inspection. These variations may indicate:

• Missing or uneven insulation
• Thermal bridges
• Air leakage
• Cold bridging around openings
• Defective installation details
• Moisture-related anomalies
• Areas requiring remedial works

Our thermal imaging service is designed to help identify these hidden problems and provide useful evidence where remedial action may be required.

Thermal imaging is especially valuable when:

• Tenants report cold rooms after retrofit
• Condensation or mould develops
• Energy savings are lower than predicted
• External wall insulation is suspected to be defective
• A complex or traditional building is being assessed
• The Retrofit Coordinator needs additional quality evidence

Used alongside Air Pressure Testing, thermography can help establish not just that a measure was installed, but whether it is performing as intended.

EPC C by 2030: the dual-metric challenge

The Warm Homes Plan confirms that private landlords will need to upgrade properties to EPC Band C across two metrics by October 2030, subject to final regulations and valid exemptions.

The proposed structure includes:

1. A fabric performance metric
   This focuses on the building envelope, including insulation, glazing and airtightness.

2. A secondary metric selected by the landlord
   This is expected to be based on either heating system performance or smart readiness, such as smart controls, solar PV or battery technology.

This means that an EPC improvement strategy cannot focus solely on replacing a boiler or adding one isolated measure. The property’s fabric performance will remain fundamental.

A landlord may install an efficient heating system, but if excessive air leakage, poor insulation continuity or thermal bridging undermines the building envelope, the property may still struggle to meet the intended performance standard.

Our Retrofit Assessment service provides a more detailed evaluation than a standard EPC. It considers the condition of the property, ventilation, occupancy, construction type, previous measures and potential interactions between proposed improvements.

That information gives you a more reliable route towards EPC C and helps prevent costly installation decisions based on incomplete data.

What landlords should do now

Waiting until 2029 to review your portfolio could leave you facing limited installer capacity, higher costs and avoidable compliance risk.

We recommend the following action plan.

1. Audit your property portfolio

Create a schedule showing:

• Current EPC rating
• EPC expiry date
• Construction type and age
• Existing insulation and heating systems
• Previous grant-funded measures
• Damp, mould or condensation reports
• Listed-building or conservation-area constraints
• Current tenant and occupancy considerations

Prioritise properties rated D, E, F or G, particularly those with known fabric defects.

2. Commission a proper Retrofit Assessment

A Retrofit Assessor is responsible for collecting the property information needed to support safe, effective recommendations. This includes condition, ventilation, energy and occupancy assessments.

Do not rely solely on an old EPC. An EPC is not a complete retrofit design document and may not identify defects that affect installation performance.

3. Appoint a qualified Retrofit Coordinator

For PAS 2035 projects, a Retrofit Coordinator oversees the process from assessment through to design, installation, monitoring and evaluation.

The Coordinator should ensure that:

• The correct PAS 2035 risk path is applied
• Measures are suitable for the property
• Ventilation is assessed and upgraded where necessary
• Installation sequencing is appropriate
• Building Regulations are addressed
• Evidence is complete and property-specific
• Defects are resolved before final sign-off

4. Build testing into the project plan

For major fabric upgrades, plan testing at the appropriate stages:

• Pre-installation baseline
• Mid-project testing where appropriate
• Post-installation verification
• Thermal imaging where defects or performance concerns exist

The exact testing requirements should be confirmed within the project’s design, risk path and scheme conditions.

5. Retain a complete evidence file

Your records should include:

• Assessment and design documents
• Photographic evidence
• Ventilation strategy
• Air pressure test results
• Thermal imaging reports where undertaken
• Product and installation information
• Commissioning records
• Technical monitoring reports
• Warranties and guarantees
• Remediation records
• Final sign-off documentation

This evidence will become increasingly important as Warm Homes Agency compliance develops and quality assurance becomes more centralised.

When retrofit fails: remediation is part of compliance

Our experience began with hands-on retrofit installation. Over more than 15 years, we have seen what poor installation looks like in practice.

We understand how a missing detail, an unsealed junction or an unsuitable insulation system can undermine an otherwise expensive project. We also know that problems are not always visible immediately. They may appear later as cold rooms, mould, condensation, poor comfort or energy savings that do not match the original modelling.

This is why Retrofit remediation services are becoming increasingly important.

Remediation may involve:

• Sealing air leakage paths
• Correcting insulation defects
• Addressing thermal bridges
• Improving ventilation
• Resolving damp or moisture risks
• Reworking defective installation details
• Reassessing an unsuitable retrofit design
• Re-testing the property after corrective works

The government’s proposed consumer protection reforms place significant emphasis on putting defective or non-compliant work right. Landlords should therefore treat remediation as a planned part of asset management, not simply an emergency response.

Why choose CPH Retrofit?

We are a one-stop shop for domestic retrofit services and energy efficiency support.

Our practical installer background means we do not assess properties in isolation from the realities of installation. We understand the pressures facing landlords, installers, councils and housing providers, while maintaining a firm focus on compliance and building performance.

Our support includes:

1. Retrofit Assessments for accurate property information
2. Retrofit Coordination aligned with PAS 2035
3. Air Pressure Testing for airtightness and leakage evidence
4. Thermal Imaging to identify hidden defects
5. C3 Technical Monitoring and compliance inspections
6. PAS 2030 Consultancy for installers and organisations
7. Retrofit measure modelling to compare cost-effective options
8. Remediation support where previous measures have failed

Our technical monitoring service supports installers through desktop audits and on-site inspections, helping identify issues early and protect long-term compliance.

Prepare now for performance-led compliance

The title of this article reflects a genuine industry shift, even though Air Pressure Testing and thermal imaging are not yet blanket legal requirements for every landlord or retrofit project.

The direction of regulation is towards stronger evidence, clearer accountability and measurable outcomes. Under PAS 2035, airtightness strategy and ventilation assessment are already critical when fabric measures are installed. For higher-risk projects, testing may be required. Thermal imaging is increasingly valuable where quality or performance is uncertain.

The landlords best prepared for EPC C by 2030 will be those who act early, understand their building stock and invest in evidence-led Whole House Retrofit.

If you need support with Warm Homes Agency compliance, PAS 2035 Compliance, Air Pressure Testing or a route to EPC C, contact CPH Retrofit. Our experienced team can help you assess your properties, coordinate compliant works and achieve the peace of mind that comes from knowing your retrofit programme is built on sound technical foundations.

This article reflects published policy and guidance available on 16 September 2026. Warm Homes Agency arrangements, EPC metrics and consumer protection requirements remain subject to further implementation and regulatory updates. Always confirm the requirements applying to your specific scheme and property.