Dashpivot article page – Part L explained

Part L explained

Part L Explained: Overview of Buildings Regulations

Part L is a section of the UK’s Building Regulations that addresses how to conserve energy in new and existing buildings, for both domestic and non-domestic use, and focuses on improving energy efficiency and reducing the UK’s carbon footprint as a stepping stone for their environmental goal to bring all greenhouse gas emissions to net zero by 2050.

Part L Objectives

Part L of Building Regulations in the UK has the following objectives:

To reduce energy consumptions used for heating, cooling, and lighting in buildings by setting U-values and standards in insulation, improving building performance, and using high-efficiency systems for heating, cooling, lighting and ventilation
To minimize greenhouse gas emissions and lowering the carbon footprint of the UK, and providing future-proof regulations
To upgrade building comfort by mandating better insulation that help maintain consistent indoor temperatures, and proper ventilation that provides better air quality
To encourage the use of renewable energy systems which are eco-friendly and cleaner alternatives than energy sources from fossil fuels
To facilitate building control and performance consistency across the UK, and provide measurable standards for energy efficiency making it easier for authorities to enforce the standards effectively.

Part L in simpler terms is a set of regulations that ensure new and existing buildings are keeping the heat in, using less electricity for systems and lights, comfortable and healthy to occupy in, using renewable energy sources, and future-proof.

Historical Context of Part L

Part L has been regularly updated and evolved throughout the years as environmental targets change with growing concerns about climate change, carbon footprint, and environmental impact of the construction industry.

Energy Efficiency Standards were first introduced around the early 1970s when there was a rise in oil crises and there was a need to lessen the dependence towards fossil fuels and conserve. The main concern wasn’t about developing eco-friendly alternatives in this period, it was about conserving oil. Although at this time, the requirements weren’t as strict and were very modest about compliance. In 1985, standards became important and the primary focus was simply reducing heat loss in buildings through basic insulation. It was in this year the Building Regulations were formalized.

In 1990, The Building Regulations introduced Part L Conservation of Fuel and Power. Even though initially, energy efficiency was only about basic thermal insulation requirements, until in 1995 they set stricter requirements for insulation, window performance and heating systems.

During the early 2000s, in order to align with climate change, Part L needed to update its regulations. Even stricter U-values were introduced for the building envelope, SAP and SBEM were also made known, and the shift into the approach “Whole-Building Performance”. It was during these years, the UK was committed to reduce carbon emissions. In 2006, the carbon emissions target changed into 20% reduction, meaning building envelopes needed lower U-values, and air testing was necessary.

In 2010, Part L was updated in line with the UK’s adoption of the Climate Change Act 2008. Renewable energy sources were mandatory such as using solar panels and heat pumps. The approach “Building Fabric First” was also introduced meaning the materials and structure of the building should be upgraded and optimized first before relying on energy systems. Insulation, air tightness, and thermal bridging across the walls, roofs, floors, windows, doors, and everything should be prioritized before considering the need for energy systems. And then in 2013, a revision was made increasing the energy efficiency of residential buildings by 6% and of non-residential buildings by 9%.

During 2021, a new policy, the Future Homes Standard, that promotes new homes built from 2025 and beyond was introduced and Part L was updated to align to the new policy. The emissions should reduce at least 30% for new homes and at least 27% for non-residential buildings, and establishments were mandated to install low-carbon heating systems like heat pumps. From then on, Part L has also included the integration of renewable energies like using solar photovoltaic (PV) panels and installing smart technologies that monitor energy usage.

Overall, Part L has been present and constantly upgrading as a response to the UK’s energy challenges and contribution to climate change, from initially conserving fossil fuel sources to implementing comprehensive energy-conservation approaches. Ultimately, its goal is to achieve net-zero targets by 2050.

You can stay across Part L Regulations with this Compliance Guide.

Who needs to comply with Part L?

There are different types of people and professionals involved in the construction of new buildings and renovation, extension, alternation or conversion of existing ones. They also take part in the compliance to Part L, starting from planning and design, up until post-occupation.

Developers or anyone who is constructing a new building or renovating, converting, or altering an existing building should ensure that the overall building design complies with Part L, and that all documents are available and present for certifications. They should ensure that all design documents are present for Building Control approval. The energy-efficient standards, insulation, air tightness, and heating systems are already built into the project even from the design stage. Even for renovations, they should ensure everything complies with Part L. Architects and designers should ensure that the building envelope should meet the U-values and minimum standards stated in Part L prior to construction, and that the overall efficiency of the building after construction should closely meet the calculated values during the design stage. They should comply with energy performance modelling, either SAP or SBEM, calculate for the U-values, and integrate renewable technologies. Anything less than the minimum standards stated in Part L should be redesigned as soon as possible. If the building owners wish to renovate, extend, alter, or convert a space in an existing building, they should ensure that the modifications or changes adhere to the latest and updated Part L regulations.

For new building owners, it is essential that they acquire a completion certificate from a Building Control body so that there are no delays in occupancy. Contractors and builders involved in the construction phase should use the materials as stated and perform methods that align with Part L regulations. Photographic evidence is also necessary, so every time they install or replace an item, these should be well-documented. They should also provide results for air tightness. Professional installers of heating, cooling, ventilation, or lighting systems should ensure that their installation procedure and items also comply with Part L. If they’re replacing an older system, it’s necessary that the replacement should adhere to the latest Part L regulation. Manufacturers producing insulation, windows, HVAC systems or other construction and building service products, should ensure that their product specifications are up-to-date with the latest Part L regulations. For homeowners with self-build projects, they should ensure their homes must comply with Part L, obtaining their own SAP assessments, calculating U-value requirements, and also undergoing air tightness testing as similar to the requirements for building owners. Part L compliance should still also be observed for renovations of self-build projects.

The entities responsible for verifying whether the buildings meet the Part L regulations are the Local Authority Building Control (LABC) Bodies, Approved Inspections, and Energy Assessors. LABC and approved inspectors check the proposed design and issue certification for building construction. These two entities ensure that everything checks outs in the Building Regulations, not only in Part L. Energy assessors conduct energy assessments and issue an Energy Performance Certification (EPC) for residential buildings or a Non-Domestic Energy Performance Certification (NDEPC) for non-residential buildings.

Importance of Energy Efficiency and Conservation of Fuel and Power in Buildings

Energy efficiency is the target of Part L, and with energy efficiency, buildings can reduce carbon emissions, lessen energy consumption, and contribute to environmental goals and sustainability.

The construction industry is one of the largest contributors to greenhouse gas emissions and by improving energy efficiency in construction and buildings, carbon emissions will actually lessen as the amount of energy consumed by buildings will lessen too. The reason why buildings contribute to emissions is mainly due to heating, cooling, and electricity usage.

By having an energy-efficient building, there’s low energy consumption and therefore low costs for electricity bills. If there’s improved insulation, efficient heating systems, and air tightness in the building, it can lessen the need for energy required in heating and cooling. If the building is a business establishment, it can help reduce the operating costs and actually aid save money for business owners.

Energy-efficient buildings, because there’s proper insulation and air tightness meaning indoor spaces are maintained at comfortable temperatures, are comfortable and healthy to live in. Proper insulation and overall design were considered leading to less heat loss. Energy-efficient ventilation systems also improve the indoor air quality and can reduce any health issues concerning the respiratory system.

Energy-efficiency means the integration of renewable energy sources as alternatives to the use of fossil fuel. Aside from reducing carbon emissions and helping create a more sustainable built environment, this can help lessen the dwindling natural resources.

The energy-efficiency target in Part L ensures that buildings are also designed to be more compatible with technologies in the future. In the event that the regulations will also be updated, buildings are “future-proofed” to be adaptable to replacements and improvements. That’ll make it easier for upgrading into other renewable energy sources, and most importantly, more cost-effective for building owners.

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About Nick Chernih

Nick is the Senior Marketing Manager at Sitemate. He wants more people in the Built World to see the potential of doing things a different way - just because things are done one way doesn't mean it's the best way for you.

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