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The Role of Lintels and Leading Levels of Energy Efficiency in New Build Homes

The Role of Lintels and Leading Levels of Energy Efficiency in New Build Homes

We take a look at The Future Homes Standard and how lintels can help developers adopt world leading levels of energy efficiency in new build homes.

According to government reports, heating and powering buildings accounts for 40% of the total energy usage in the UK. By making the buildings more energy efficient and embracing smart technologies, household energy bills can be cut, the demand for energy will be reduced, and economic growth will be given a boost and carbon reduction target can also be met.

As part of his Spring Statement, Chancellor Philip Hammond announced that the government will therefore introduce a Future Homes Standard that will mark the end of the use of ‘fossil fuel heating systems’ in all new homes by 2025. This means that over the next six years housing developers will be required to use low-carbon heating systems in all new build homes.

The introduction of the new standard is as a result of the Prime Minister’s Industrial Strategy Grand Challenge, which includes a mission to at least halve the energy use of new buildings by 2030, and adopt ‘world leading levels’ of energy efficiency in all new build homes by 2025.

As well as integrating lower carbon heating systems, to meet these targets there are additional steps that can be taken by developers to achieve more environmentally friendly homes. This includes the use of innovative products that can help in improving the energy efficiency of the structure.

When it comes to thermal efficiency our thoughts naturally turn to windows, doors and insulation, however the choice of lintel has a surprising impact too.

Traditional single piece lintels that are often used in the construction of houses allow the transfer of heat to the outside. This is because standard lintels are made from a single piece of highly conductive steel which interrupts the line of insulation in the cavity wall causing thermal bridging. This is where there is a significantly higher heat transfer than the surrounding, insulated elements.

With a typical dwelling having 8-10 windows and two doors, thermal bridging through single-piece lintels can account for around a third of the total heat loss. As such, taking steps to minimise thermal bridging along the lintel can be a very cost-effective and reliable method of working towards meeting the energy efficiency levels set out in the new Future Homes Standard. It also makes the property attractive to prospective buyers or tenants.

Psi Values – How low can you go?

The thermal bridging performance of a lintel is expressed in terms of its Psi value – the lower the Psi value, the better the thermal performance.

Latest generation lintels such as our Supatherm range are able to achieve a Psi value of between 0.03 and 0.06. Energy assessors, when working on a building constructed to Part L Accredited Construction Detail, tend to use an approved value of 0.3W/mK for lintels without a baseplate. In reality, a heat loss of 0.3W/mK makes the assumption that the line of insulation is interrupted with a highly conductive, traditional steel lintel.

However, this does not reflect actual heat loss from latest generation, thermally broken lintels. For instance, even with our 1500mm standard lintel the Psi Value is 0.18 W/mK, although upgrading to our Supatherm lintel at the same length improves thermal performance to 0.043 W/mK. Replacing a traditional lintel made from a single piece of metal with a thermally broken lintel can therefore cut heat loss through thermal bridging by over 75% and make significant improvements in SAP calculations.

In terms of actual performance, a thermally broken lintel can improve both the dwellings CO2 emission rate (DER) and fabric energy efficiency rate (DFEE) by 3% and 1% respectively. In the case of a small detached dwelling of around 105m² the reduction in heat loss from a thermally broken lintel is equivalent to upgrading from double to triple glazed windows.

Summary

The impact of upgrading to a super-insulated lintel is even greater on a larger detached dwelling of 304m², which can mean the cavity wall thickness is reduced from 150 to 125mm. This is another significant saving for builders in terms of insulation and masonry ancillaries. It also avoids the loss of internal living space as wider cavities have a tendency to encroach on the internal footprint.

The standards in energy efficiency for all new buildings, including newly developed homes, become ever stricter. By ensuring a property has thermally broken lintel, developers can make a significant difference to overall performance and take a step towards meeting the Future Homes Standard sooner.

Take a look at our full lintel range here

PSI Value Calculator

Part of the Birtley Group

Birtley began life as Birtley Building Products in 1965, based at the current site in County Durham. Originally a steel fabricator for the area’s mining and power generation industries, the company made its first steel lintels in 1967. Since then, Birtley has grown from reliable local supplier to a UK-wide force in construction design technology and product development.

In 1889, the British Metal Expansion Company was established in Hartlepool. It had sole European rights for the manufacture of expanded metal mesh, mainly for use as reinforcement and lath in the rapidly expanding sector of concrete construction. The business that grew from these early days later changed its name to Expamet.


Acquired by Birtley Group in 2015, Bowater Doors is a nationally-known name synonymous with top quality and imaginative composite residential door design and manufacture.

The product portfolio offers exclusive ranges for trade installers and a retail range providing doors direct to consumer and social housing organisations.

Birtley Galvanizing boasts one of the most impressive galvanizing plants in Europe. The plant achieves the finest quality hot-dip galvanized zinc protective coatings to BS EN ISO 1461. Using state-of-the-art technology the plant processes steel products using a computer controlled, automated handling system, enabling Birtley Galvanizing to provide full project solutions to many industries.