Driving resource-efficient building performance

Aircrete, with its inherent insulating performance, makes a positive contribution to the overall energy efficiency of buildings in use.

Buildings in use are responsible for around 23% of the total Greenhouse Gas Emissions from the UK, according to the Climate Change Committee’s sixth annual carbon budget. The biggest contributor is the burning of fossil fuels for heating, with the generation of electricity for lighting and appliances making up most of the remainder.  Our homes account for the vast majority (77%) of these emissions.

This is not inevitable: the way homes are designed and built, and the materials used in their construction can all have an impact. Aircrete, with its inherent thermal efficiency, low thermal bridging and efficient airtightness, make a positive contribution to the energy efficiency of new homes.

Fabric first

We support a “fabric first” philosophy. This means that we believe energy efficiency should be built into the fabric of a house so that it remains effective for the lifetime of the building. We believe this is a better option than relying on technologies that are either unproven over the long term, or that rely on the behaviour of the building occupants for their effect.

The millions of tiny air bubbles trapped within a Celcon Block provide a wide range of benefits including excellent thermal insulation, which reduces energy use within a building.

When combined with other building materials such as brick and insulation products, extremely low U-Values can be achieved, easily meeting the requirements of the energy aspects of the UK's Building Regulations (such as Part L in England).

The most recent revision of Approved Document L, which came into operation in June 2022, increased the thermal performance required of external walls in houses.

External walls now effectively need to demonstrate a U-value of 0.18W/m2K. H+H has published a directory of U-Value calculations detailing a huge range of external wall designs – both solid and cavity constructions – that meet this demanding performance standard using its aircrete products.

High performance buildings

When using our Thin-Joint System or H+H Vertical Wall Panels, it’s also possible to build airtight structures extremely efficiently. Our blocks have been used as the basis of both Passivhaus certified homes and zero carbon buildings.

In fact, as long ago as 2007 H+H aicrete was used as the basis for the demonstration zero carbon house constructed at the Building Research Establishment (BRE).

BRE has also demonstrated that the use of aircrete can significantly reduce heat loss at thermal bridges within a building, such as at the junctions of walls and floors.

Being of a relatively high mass compared to lightweight timber framed structures, walls built with aircrete can provide a high degree of thermal mass helping to create a comfortable internal environment in the building.

Increasing lifecycle

But even as the list of increasingly stringent regulations for new build homes grows, there doesn’t appear to be any official guidance requiring a minimum lifespan once built.

The Green Guide to Housing Specification attempts to determine a 60-year design life seems to be the accepted norm, but this may be a somewhat arbitrary figure.

The fact is, facing a growing population, if we continue to build houses at our current rate, any house built today will need to last for many, many multiples of 60 years.

From an environmentally conscious perspective, to determine a new building’s impact on the environment, we are asked to consider the embodied as well as the operational carbon footprint, but this can only be done if it is considered over the lifespan of the building. Longevity is a major issue to ensure a house is as ethical as it can be.

At H+H, we believe that the lifespan of a building is as important as its energy efficiency when it comes to environmental impact. Achieving the maximum possible lifespan for a building surely has to be an objective for the construction sector.

The complete life cycle of an aircrete block is indeed an extremely long one, with a life expectancy of some 150 years, well in excess of the Green Guide to Housing Specification’s 60 years. During that time, it doesn’t emit any harmful substances or require preservatives to maintain performance.