In this post we discuss changes coming in June 2025 to RdSAP10 EPCs and Air Tightness Testing. This brings in new opportunities to those looking to improve their homes energy performance rating and perhaps looking for a light touch retrofit, an easy win or merely a more accurate Energy Performance Certificate.
EPC Updates – RdSAP10 Methodology Changes
In the realm of home energy assessment, the Reduced Data Standard Assessment Procedure (rdSAP) plays a crucial role in evaluating the energy efficiency of existing homes. However, recent developments in building regulations and testing methods are revolutionizing the way we understand and assess energy performance. Let’s delve into how these changes are reshaping the landscape of energy performance certificates (EPCs) and unlocking new opportunities for homeowners, landlords, and energy assessors alike.
What is RdSAP: Streamlining Domestic Energy Assessment
At its core, RdSAP employs a simplified methodology to produce Energy Performance Certificates (EPCs) for existing homes. This approach, often referred to as ‘reduced data,’ aims to assess energy efficiency in a non-invasive, rapid, and cost-effective manner. By inputting key information such as property age and primary construction materials, assessors can leverage inference tables to infer thermal characteristics based on historical building standards.
One critical aspect of RdSAP assessment is estimating uncontrolled air leakage, a significant contributor to heat loss in homes. Traditionally, this estimation relied on visual inspections by energy assessors, leading to assumptions about air permeability based on factors like floor construction and window types.
A Shift to On-site Measured Airtightness
However, recent regulatory changes are driving a paradigm shift in how we approach air leakage assessment. Under current building regulations (Part L), all new dwellings must undergo air pressure testing, aiming to quantify the extent of uncontrolled air leakage. Moreover, existing homes undergoing retrofit works with grant funding may also require pressure testing.
This shift towards standardized air pressure testing introduces a more accurate and objective method for assessing airtightness. With the introduction of RdSAP 10 methodology, assessors can now directly input measured airtightness test results into EPCs, providing a more precise reflection of a home’s energy performance.
The Impact of Draughts on Heat Loss
A draught is an unwanted current of air, usually cold, that enters or exits through gaps in the building’s envelope. These gaps can be around windows, doors, walls, floors, and ceilings, causing discomfort, increased heating costs, and potentially damp problems.
Historic England estimates that draughts can contribute to up to 30% of heat loss in a typical home.
Draughts not only have an impact on thermal comfort in the home, but ultimately contribute to the heating cost and therefore reduce draughts can have a real impact on the energy rating.
Air Testing Methodologies: Blower Door vs Pulse
Two prevalent methods for air pressure testing are Blower Door (Q50) and Pulse (Q4). These methods measure the air tightness of a building envelope under specified conditions, with lower test scores indicating lower energy use, carbon emissions, and running costs.
Here at Building Compliance Testing, we tend to use the Blower Door methodology.
Here are some benefits of a blower door fan test over a pulse test. Learn more below for the reasons why.
Real-Time Data
Blower door tests provide real-time data on a building’s airtightness, allowing for immediate adjustments or interventions if necessary. In contrast, pulse tests may require additional analysis and interpretation of the results.
Versatility
Blower door tests can be used in various building types and sizes, including both residential and commercial buildings. They can also be conducted at different pressure differentials to assess airtightness under various conditions. Pulse tests, on the other hand, may have limitations in terms of building compatibility and pressure differentials.
Quantitative Results
Blower door tests typically provide quantitative measurements of a building’s air leakage rate, allowing for precise assessment and comparison. Pulse tests may provide qualitative information but may not offer the same level of quantitative detail.
Diagnostic Capability
Blower door tests can help pinpoint specific areas of air leakage within a building, facilitating targeted repairs or improvements. The pressurization and depressurization capabilities of blower door tests allow for more detailed diagnostic analysis. Pulse tests may provide an overall assessment of a building’s airtightness but may lack the diagnostic precision of blower door tests.
Overall, while both blower door tests and pulse tests serve their purpose in assessing a building’s airtightness, blower door tests offer real-time data, versatility, quantitative results, and diagnostic capabilities that may make them preferable in many situations.
EPC and Domestic Retrofit Opportunities
The integration of measured airtightness test results into rdSAP 10 presents various opportunities across the housing sector:
- Landlords can receive recognition for efforts to minimize air leakage, updating EPCs to reflect actual airtightness.
- Cost-effective interventions to reduce air leakage can be acknowledged in EPCs, incentivizing energy-efficient upgrades.
- Homeowners gain insight into their home’s airtightness, fostering interest in energy efficiency improvements.
- Airtightness testing conducted for other purposes, such as PAS2035 compliance, can now contribute to EPCs.
Unlocking Real-world Measurement
As we embrace these advancements in energy assessment, the potential for improving energy efficiency in homes becomes more tangible. By leveraging measured airtightness test results, rdSAP 10 empowers stakeholders to make informed decisions that not only enhance EPC ratings but also contribute to a more sustainable future. With software updates expected to roll out in June 2025, we anticipate a significant step forward in the journey towards more energy-efficient homes.
How can Building Compliance Testing help?
We are accredited ATTMA air permeability test engineers and Elmhurst Energy accredited domestic energy assessors. We have over 10 years real world on-site experienced meaning we are well placed to serve this new market.
Have a Project in mind? Let’s get to work!
RdSAP10 EPCs and Air Tightness Testing integration come with greater accuracy reporting of our housing stock and an opportunity for all to begin their journey to net-zero with a low cost entry point to domestic retrofit.
Contact us now.
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